Obstetrics

The results of the highly anticipated Antenatal Late Preterm Study recently have become available.¹ Data from this randomized controlled trial, conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network, demonstrated that administration of betamethasone to women at risk for preterm delivery between 34 weeks 0 days and 36 weeks 6 days of gestation significantly reduces the rate of neonatal respiratory complications. It may represent the largest study of antenatal corticosteroids (ACS) to date, with 2,827 infants studied, and its results inevitably lead to the logical practical question: Should ACS use be extended beyond the 34 weeks’ gestation limit previously recommended by professional guidelines in the United States²?

There are some issues that bear discussion before such a significant change in standard of care should be promoted.²

Antenatal Late Preterm Study outcomesThe primary outcome in the study was a composite end point describing the need for respiratory support within 72 hours after birth. Based on a pilot study, the investigators had anticipated a 33% decrease in the rate of the primary outcome; however, the reduction was only 20% (relative risk [RR], 0.80; 95% confidence interval [CI], 0.66−0.97). Although the effect size was statistically significant, one could question the clinical relevance of such a small difference.

A 33% reduction effect, more consistent with the preliminary expectations, was noted in the prespecified secondary composite outcome of severe respiratory complications (RR, 0.67; 95% CI, 0.53−0.84). Occurrences included in the secondary composite outcome that also showed significant rate reductions were:

The reported reduction in bronchopulmonary dysplasia (RR, 0.22; 95% CI, 0.02−0.92) cannot plausibly be attributed to ACS. Randomized data aggregated by the Cochrane Database of Systematic Reviews³ do not show improvement in chronic lung disease with ACS use. Moreover, the authors recognize that the assessment for bronchopulmonary dysplasia at only 28 days of life is only partially informative and that longer childhood follow-up is required to confirm the finding.

We recommend caution before changing current practiceWe propose prudence with ACS use after 34 weeks’ gestation for the following reasons: the increased risk for neonatal hypoglycemia associated with ACS, the increased risk for ACS-related harm in term-born babies, and safety concerns with ACS in the late preterm period.

Evidence shows an increased risk for neonatal hypoglycemiaThe most profound effect modification observed in the study was an adverse effect—namely, a 60% increase in neonatal hypoglycemia with ACS administration (RR, 1.6; 95% CI, 1.37−1.87). The rate of neonatal hypoglycemia was 24% in the ACS group, compared with 15% in the placebo group.

Results of prior studies have demonstrated either no increased risk of hypoglycemia with ACS use⁴⁻⁷ or a much smaller increase (from 4.2% to 5.7%).⁸ The higher rate of neonatal hypoglycemia seen in this study suggests the possibility that the late preterm population may be more vulnerable to the negative impact of ACS on neonatal glucose/insulin homeostasis. Presumed mechanisms of action are either maternal hyperglycemia or fetal adrenal suppression or both, with potential for fetal adrenal suppression resulting from betamethasone exposure to affect long-term metabolic outcomes.⁹

Of note, women with pregestational diabetes were excluded from the study and, in routine practice, inclusion of such patients may further increase the risk of neonatal hypoglycemia.

There are few data on the prognostic significance of neonatal hypoglycemia in preterm infants, with the exception of a single study, the results of which show that it is associated with adverse neurodevelopment at 18 months of age.¹⁰

Data reveal increased risk for harm in term-born babiesIn spite of strict protocol specifications to increase the probability of delivery before 37 weeks’ gestation, 16% of women in the trial delivered at term. Investigators of prior randomized studies of ACS, aimed at reducing the risks of prematurity, have reported a rate of term delivery of about one-third,^4,11 and in routine practice, administration of ACS after 34 weeks may be associated with even higher rates of term delivery.

This is important because recent evidence shows an unfavorable impact of ACS exposure in term-born children.¹² The 5-year follow-up of the largest randomized trial in which multiple ACS courses were used noted that babies born at term had a 4-fold increased odds ratio for neurosensory disability.¹¹ There was no dose−response interaction, with the same adverse odds ratio after 1 or 4 additional ACS courses. This observation was consistent with a previously reported Swedish national cohort, pointing to an unfavorable impact of even a single course of ACS in term-born children, with a greater likelihood of harm than benefit.¹³

In a UK follow-up of children aged 8 to 15 years who were enrolled in an RCT of ACS before cesarean delivery at term, low academic achievement was significantly more common in the group whose mothers had received ACS.¹⁴ In another study of 304 children born at term after exposure to a single course of ACS, investigators noted significantly increased cortisol reactivity to acute psychological stress at ages 6 to 11 years in the ACS-exposed patients, compared with 212 babies of women with threatened preterm labor who did not receive ACS and 372 babies from uncomplicated term pregnancies.¹⁵

The relevance of such study findings extends beyond childhood given the fact that elevated hypothalamic-pituitary-adrenal (HPA) axis reactivity has been linked to the pathogenesis of metabolic syndrome and depression in adult life.¹⁶ As recently as 2015, investigators of a randomized trial of ACS in 6 low- and middle-income countries highlighted their concern regarding “potentially harmful use of antenatal corticosteroids for infants not delivered preterm.”¹⁷

There are safety concerns with ACS in the late preterm periodThe effects of ACS are more pleiotropic than those reflected in a lower incidence of respiratory difficulties. Knowledge of the overall consequences of ACS exposure in infants born late-preterm or at term is still limited. The close-to-term fetus exposed to exogenous corticosteroids is also exposed to the physiologic endogenous surge of cortisol known to occur in the maternal circulation in late pregnancy, which reaches levels 3 times higher than those seen in nonpregnant women.¹⁸ Although placental 11 beta-hydroxysteroid dehydrogenase type 2 plays a protective role by allowing no more than 10% to 20% of maternal corticosteroids to cross the placenta, fetal overexposure from concomitant exogenous maternal corticosteroid administration remains a theoretical concern close to term. This is especially worrisome if there is a gestational age−related increase in the sensitivity to corticosteroid-induced in utero fetal programming. It has been reported that fetal overexposure to corticosteroids in late pregnancy can permanently increase the activity of the HPA-axis, with likely consequences in adult life.¹⁹

Another concern relates to oligodendrocytes development. Although the neuronal division process in humans usually is completed by 24 weeks’ gestation, the most rapid growth for oligodendrocytes occurs between 34 and 36 weeks’ gestation; these are the cells responsible for the synthesis of myelin. Overexposure to corticosteroids at this vulnerable time in the late preterm fetus potentially may have unanticipated negative neurologic consequences.²⁰

Where should future studies focus?There is clear neonatal benefit from a single course of ACS given to women who will deliver before 34 weeks’ gestation. It is widely accepted, based on the evidence provided by the 30-year follow-up of the cohort of 534 participants from the Auckland trial (the longest follow-up for any pregnancy trial), that administration of ACS at less than 34 weeks’ gestation is not associated with any obvious major developmental risk.²¹⁻²³

However, the reassurances provided by the Auckland cohort should be neither directly extrapolated to the administration of ACS in the late preterm period nor applied to term-born babies exposed to ACS, for the simple reason that these subgroups never have been analyzed separately. The risk:benefit ratio of ACS use in the late-preterm period is as yet unknown, and in term-born babies the ratio may be unfavorable.

Follow-up studies are neededWe consider that there is a vital need for long-term follow-up studies. The focus of research on the effects of ACS no longer is on the immediate neonatal outcomes and now is on safety and the long-term outcomes of this exposure.

Bottom lineWe regard the large, high-quality study conducted by the NICHD MFMU Network¹ as an opportunity to answer current concerns. It is hoped that the resources necessaryfor in-depth follow-up of the children involved in this study will be provided to the investigators and to the NICHD. It is only with such follow-up that mid- and long-term adverse effects can be assessed. We believe that, at a minimum, mid-term follow-up data should be available before it is wise to make any definitive recommendations for a sweeping change in clinical practice.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

The results of the highly anticipated Antenatal Late Preterm Study recently have become available.¹ Data from this randomized controlled trial, conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network, demonstrated that administration of betamethasone to women at risk for preterm delivery between 34 weeks 0 days and 36 weeks 6 days of gestation significantly reduces the rate of neonatal respiratory complications. It may represent the largest study of antenatal corticosteroids (ACS) to date, with 2,827 infants studied, and its results inevitably lead to the logical practical question: Should ACS use be extended beyond the 34 weeks’ gestation limit previously recommended by professional guidelines in the United States²?

There are some issues that bear discussion before such a significant change in standard of care should be promoted.²

Antenatal Late Preterm Study outcomesThe primary outcome in the study was a composite end point describing the need for respiratory support within 72 hours after birth. Based on a pilot study, the investigators had anticipated a 33% decrease in the rate of the primary outcome; however, the reduction was only 20% (relative risk [RR], 0.80; 95% confidence interval [CI], 0.66−0.97). Although the effect size was statistically significant, one could question the clinical relevance of such a small difference.

A 33% reduction effect, more consistent with the preliminary expectations, was noted in the prespecified secondary composite outcome of severe respiratory complications (RR, 0.67; 95% CI, 0.53−0.84). Occurrences included in the secondary composite outcome that also showed significant rate reductions were:

The reported reduction in bronchopulmonary dysplasia (RR, 0.22; 95% CI, 0.02−0.92) cannot plausibly be attributed to ACS. Randomized data aggregated by the Cochrane Database of Systematic Reviews³ do not show improvement in chronic lung disease with ACS use. Moreover, the authors recognize that the assessment for bronchopulmonary dysplasia at only 28 days of life is only partially informative and that longer childhood follow-up is required to confirm the finding.

We recommend caution before changing current practiceWe propose prudence with ACS use after 34 weeks’ gestation for the following reasons: the increased risk for neonatal hypoglycemia associated with ACS, the increased risk for ACS-related harm in term-born babies, and safety concerns with ACS in the late preterm period.

Evidence shows an increased risk for neonatal hypoglycemiaThe most profound effect modification observed in the study was an adverse effect—namely, a 60% increase in neonatal hypoglycemia with ACS administration (RR, 1.6; 95% CI, 1.37−1.87). The rate of neonatal hypoglycemia was 24% in the ACS group, compared with 15% in the placebo group.

Results of prior studies have demonstrated either no increased risk of hypoglycemia with ACS use⁴⁻⁷ or a much smaller increase (from 4.2% to 5.7%).⁸ The higher rate of neonatal hypoglycemia seen in this study suggests the possibility that the late preterm population may be more vulnerable to the negative impact of ACS on neonatal glucose/insulin homeostasis. Presumed mechanisms of action are either maternal hyperglycemia or fetal adrenal suppression or both, with potential for fetal adrenal suppression resulting from betamethasone exposure to affect long-term metabolic outcomes.⁹

Of note, women with pregestational diabetes were excluded from the study and, in routine practice, inclusion of such patients may further increase the risk of neonatal hypoglycemia.

There are few data on the prognostic significance of neonatal hypoglycemia in preterm infants, with the exception of a single study, the results of which show that it is associated with adverse neurodevelopment at 18 months of age.¹⁰

Data reveal increased risk for harm in term-born babiesIn spite of strict protocol specifications to increase the probability of delivery before 37 weeks’ gestation, 16% of women in the trial delivered at term. Investigators of prior randomized studies of ACS, aimed at reducing the risks of prematurity, have reported a rate of term delivery of about one-third,^4,11 and in routine practice, administration of ACS after 34 weeks may be associated with even higher rates of term delivery.

This is important because recent evidence shows an unfavorable impact of ACS exposure in term-born children.¹² The 5-year follow-up of the largest randomized trial in which multiple ACS courses were used noted that babies born at term had a 4-fold increased odds ratio for neurosensory disability.¹¹ There was no dose−response interaction, with the same adverse odds ratio after 1 or 4 additional ACS courses. This observation was consistent with a previously reported Swedish national cohort, pointing to an unfavorable impact of even a single course of ACS in term-born children, with a greater likelihood of harm than benefit.¹³

In a UK follow-up of children aged 8 to 15 years who were enrolled in an RCT of ACS before cesarean delivery at term, low academic achievement was significantly more common in the group whose mothers had received ACS.¹⁴ In another study of 304 children born at term after exposure to a single course of ACS, investigators noted significantly increased cortisol reactivity to acute psychological stress at ages 6 to 11 years in the ACS-exposed patients, compared with 212 babies of women with threatened preterm labor who did not receive ACS and 372 babies from uncomplicated term pregnancies.¹⁵

The relevance of such study findings extends beyond childhood given the fact that elevated hypothalamic-pituitary-adrenal (HPA) axis reactivity has been linked to the pathogenesis of metabolic syndrome and depression in adult life.¹⁶ As recently as 2015, investigators of a randomized trial of ACS in 6 low- and middle-income countries highlighted their concern regarding “potentially harmful use of antenatal corticosteroids for infants not delivered preterm.”¹⁷

There are safety concerns with ACS in the late preterm periodThe effects of ACS are more pleiotropic than those reflected in a lower incidence of respiratory difficulties. Knowledge of the overall consequences of ACS exposure in infants born late-preterm or at term is still limited. The close-to-term fetus exposed to exogenous corticosteroids is also exposed to the physiologic endogenous surge of cortisol known to occur in the maternal circulation in late pregnancy, which reaches levels 3 times higher than those seen in nonpregnant women.¹⁸ Although placental 11 beta-hydroxysteroid dehydrogenase type 2 plays a protective role by allowing no more than 10% to 20% of maternal corticosteroids to cross the placenta, fetal overexposure from concomitant exogenous maternal corticosteroid administration remains a theoretical concern close to term. This is especially worrisome if there is a gestational age−related increase in the sensitivity to corticosteroid-induced in utero fetal programming. It has been reported that fetal overexposure to corticosteroids in late pregnancy can permanently increase the activity of the HPA-axis, with likely consequences in adult life.¹⁹

Another concern relates to oligodendrocytes development. Although the neuronal division process in humans usually is completed by 24 weeks’ gestation, the most rapid growth for oligodendrocytes occurs between 34 and 36 weeks’ gestation; these are the cells responsible for the synthesis of myelin. Overexposure to corticosteroids at this vulnerable time in the late preterm fetus potentially may have unanticipated negative neurologic consequences.²⁰

Where should future studies focus?There is clear neonatal benefit from a single course of ACS given to women who will deliver before 34 weeks’ gestation. It is widely accepted, based on the evidence provided by the 30-year follow-up of the cohort of 534 participants from the Auckland trial (the longest follow-up for any pregnancy trial), that administration of ACS at less than 34 weeks’ gestation is not associated with any obvious major developmental risk.²¹⁻²³

However, the reassurances provided by the Auckland cohort should be neither directly extrapolated to the administration of ACS in the late preterm period nor applied to term-born babies exposed to ACS, for the simple reason that these subgroups never have been analyzed separately. The risk:benefit ratio of ACS use in the late-preterm period is as yet unknown, and in term-born babies the ratio may be unfavorable.

Follow-up studies are neededWe consider that there is a vital need for long-term follow-up studies. The focus of research on the effects of ACS no longer is on the immediate neonatal outcomes and now is on safety and the long-term outcomes of this exposure.

Bottom lineWe regard the large, high-quality study conducted by the NICHD MFMU Network¹ as an opportunity to answer current concerns. It is hoped that the resources necessaryfor in-depth follow-up of the children involved in this study will be provided to the investigators and to the NICHD. It is only with such follow-up that mid- and long-term adverse effects can be assessed. We believe that, at a minimum, mid-term follow-up data should be available before it is wise to make any definitive recommendations for a sweeping change in clinical practice.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

The results of the highly anticipated Antenatal Late Preterm Study recently have become available.¹ Data from this randomized controlled trial, conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network, demonstrated that administration of betamethasone to women at risk for preterm delivery between 34 weeks 0 days and 36 weeks 6 days of gestation significantly reduces the rate of neonatal respiratory complications. It may represent the largest study of antenatal corticosteroids (ACS) to date, with 2,827 infants studied, and its results inevitably lead to the logical practical question: Should ACS use be extended beyond the 34 weeks’ gestation limit previously recommended by professional guidelines in the United States²?

There are some issues that bear discussion before such a significant change in standard of care should be promoted.²

Antenatal Late Preterm Study outcomesThe primary outcome in the study was a composite end point describing the need for respiratory support within 72 hours after birth. Based on a pilot study, the investigators had anticipated a 33% decrease in the rate of the primary outcome; however, the reduction was only 20% (relative risk [RR], 0.80; 95% confidence interval [CI], 0.66−0.97). Although the effect size was statistically significant, one could question the clinical relevance of such a small difference.

A 33% reduction effect, more consistent with the preliminary expectations, was noted in the prespecified secondary composite outcome of severe respiratory complications (RR, 0.67; 95% CI, 0.53−0.84). Occurrences included in the secondary composite outcome that also showed significant rate reductions were:

The reported reduction in bronchopulmonary dysplasia (RR, 0.22; 95% CI, 0.02−0.92) cannot plausibly be attributed to ACS. Randomized data aggregated by the Cochrane Database of Systematic Reviews³ do not show improvement in chronic lung disease with ACS use. Moreover, the authors recognize that the assessment for bronchopulmonary dysplasia at only 28 days of life is only partially informative and that longer childhood follow-up is required to confirm the finding.

We recommend caution before changing current practiceWe propose prudence with ACS use after 34 weeks’ gestation for the following reasons: the increased risk for neonatal hypoglycemia associated with ACS, the increased risk for ACS-related harm in term-born babies, and safety concerns with ACS in the late preterm period.

Evidence shows an increased risk for neonatal hypoglycemiaThe most profound effect modification observed in the study was an adverse effect—namely, a 60% increase in neonatal hypoglycemia with ACS administration (RR, 1.6; 95% CI, 1.37−1.87). The rate of neonatal hypoglycemia was 24% in the ACS group, compared with 15% in the placebo group.

Results of prior studies have demonstrated either no increased risk of hypoglycemia with ACS use⁴⁻⁷ or a much smaller increase (from 4.2% to 5.7%).⁸ The higher rate of neonatal hypoglycemia seen in this study suggests the possibility that the late preterm population may be more vulnerable to the negative impact of ACS on neonatal glucose/insulin homeostasis. Presumed mechanisms of action are either maternal hyperglycemia or fetal adrenal suppression or both, with potential for fetal adrenal suppression resulting from betamethasone exposure to affect long-term metabolic outcomes.⁹

Of note, women with pregestational diabetes were excluded from the study and, in routine practice, inclusion of such patients may further increase the risk of neonatal hypoglycemia.

There are few data on the prognostic significance of neonatal hypoglycemia in preterm infants, with the exception of a single study, the results of which show that it is associated with adverse neurodevelopment at 18 months of age.¹⁰

Data reveal increased risk for harm in term-born babiesIn spite of strict protocol specifications to increase the probability of delivery before 37 weeks’ gestation, 16% of women in the trial delivered at term. Investigators of prior randomized studies of ACS, aimed at reducing the risks of prematurity, have reported a rate of term delivery of about one-third,^4,11 and in routine practice, administration of ACS after 34 weeks may be associated with even higher rates of term delivery.

This is important because recent evidence shows an unfavorable impact of ACS exposure in term-born children.¹² The 5-year follow-up of the largest randomized trial in which multiple ACS courses were used noted that babies born at term had a 4-fold increased odds ratio for neurosensory disability.¹¹ There was no dose−response interaction, with the same adverse odds ratio after 1 or 4 additional ACS courses. This observation was consistent with a previously reported Swedish national cohort, pointing to an unfavorable impact of even a single course of ACS in term-born children, with a greater likelihood of harm than benefit.¹³

In a UK follow-up of children aged 8 to 15 years who were enrolled in an RCT of ACS before cesarean delivery at term, low academic achievement was significantly more common in the group whose mothers had received ACS.¹⁴ In another study of 304 children born at term after exposure to a single course of ACS, investigators noted significantly increased cortisol reactivity to acute psychological stress at ages 6 to 11 years in the ACS-exposed patients, compared with 212 babies of women with threatened preterm labor who did not receive ACS and 372 babies from uncomplicated term pregnancies.¹⁵

The relevance of such study findings extends beyond childhood given the fact that elevated hypothalamic-pituitary-adrenal (HPA) axis reactivity has been linked to the pathogenesis of metabolic syndrome and depression in adult life.¹⁶ As recently as 2015, investigators of a randomized trial of ACS in 6 low- and middle-income countries highlighted their concern regarding “potentially harmful use of antenatal corticosteroids for infants not delivered preterm.”¹⁷

There are safety concerns with ACS in the late preterm periodThe effects of ACS are more pleiotropic than those reflected in a lower incidence of respiratory difficulties. Knowledge of the overall consequences of ACS exposure in infants born late-preterm or at term is still limited. The close-to-term fetus exposed to exogenous corticosteroids is also exposed to the physiologic endogenous surge of cortisol known to occur in the maternal circulation in late pregnancy, which reaches levels 3 times higher than those seen in nonpregnant women.¹⁸ Although placental 11 beta-hydroxysteroid dehydrogenase type 2 plays a protective role by allowing no more than 10% to 20% of maternal corticosteroids to cross the placenta, fetal overexposure from concomitant exogenous maternal corticosteroid administration remains a theoretical concern close to term. This is especially worrisome if there is a gestational age−related increase in the sensitivity to corticosteroid-induced in utero fetal programming. It has been reported that fetal overexposure to corticosteroids in late pregnancy can permanently increase the activity of the HPA-axis, with likely consequences in adult life.¹⁹

Another concern relates to oligodendrocytes development. Although the neuronal division process in humans usually is completed by 24 weeks’ gestation, the most rapid growth for oligodendrocytes occurs between 34 and 36 weeks’ gestation; these are the cells responsible for the synthesis of myelin. Overexposure to corticosteroids at this vulnerable time in the late preterm fetus potentially may have unanticipated negative neurologic consequences.²⁰

Where should future studies focus?There is clear neonatal benefit from a single course of ACS given to women who will deliver before 34 weeks’ gestation. It is widely accepted, based on the evidence provided by the 30-year follow-up of the cohort of 534 participants from the Auckland trial (the longest follow-up for any pregnancy trial), that administration of ACS at less than 34 weeks’ gestation is not associated with any obvious major developmental risk.²¹⁻²³

However, the reassurances provided by the Auckland cohort should be neither directly extrapolated to the administration of ACS in the late preterm period nor applied to term-born babies exposed to ACS, for the simple reason that these subgroups never have been analyzed separately. The risk:benefit ratio of ACS use in the late-preterm period is as yet unknown, and in term-born babies the ratio may be unfavorable.

Follow-up studies are neededWe consider that there is a vital need for long-term follow-up studies. The focus of research on the effects of ACS no longer is on the immediate neonatal outcomes and now is on safety and the long-term outcomes of this exposure.

Bottom lineWe regard the large, high-quality study conducted by the NICHD MFMU Network¹ as an opportunity to answer current concerns. It is hoped that the resources necessaryfor in-depth follow-up of the children involved in this study will be provided to the investigators and to the NICHD. It is only with such follow-up that mid- and long-term adverse effects can be assessed. We believe that, at a minimum, mid-term follow-up data should be available before it is wise to make any definitive recommendations for a sweeping change in clinical practice.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

“SHOULD YOU ADOPT THE PRACTICE OF VAGINAL CLEANSING WITH POVIDONE-IODINE PRIOR TO CESAREAN DELIVERY?”
ROBERT L. BARBIERI, MD (EDITORIAL; JANUARY 2016)
In his January 2016 Editorial, Editor in Chief Robert L. Barbieri, MD, presented evidence supporting the practice of vaginal cleansing with povidone-iodine prior to cesarean delivery (CD) to prevent postoperative endometritis. He then asked readers if they would consider adopting such a practice. More than 250 readers weighed in through the Quick Poll at obgmanagement.com, and many readers sent in letters with follow-up questions and comments on controlling bacterial contamination, vaginal seeding, etc. Here are some of the letters, along with Dr. Barbieri’s response and the Quick Poll results.

A contradiction in definitions?
There seems to be a contradiction in definitions. The second sentence of the article defines endometritis as the presence of fever plus low abdominal tenderness. However, the studies presented state that vaginal cleansing pre-CD decreased endometritis but did not decrease postpartum fever. Is this not a discrepancy?
Nancy Kerr, MD, MPH
Albuquerque, New Mexico

A question about povidone-iodine
Have any studies been done on newborn iodine levels after vaginal cleansing with povidone-iodine prior to CD?
G. Millard Simmons Jr, MD
Hilton Head, Bluffton, South Carolina

Additional tips for controlling bacterial contamination
Dr. Barbieri’s editorial on vaginal cleansing prior to CD is eye opening. I have a few additional suggestions to control bacterial contamination.

First, I examine my patients in labor as few times as necessary, and I ask the nurses (RNs) not to place their fingers in the patient’s vagina while she is pushing. I remove the Foley catheter when I feel progress (descent of fetal head) is being achieved. In addition, physicians as well as RNs should consider changing their scrubs between deliveries, as I believe that bacterial contamination is splattered all over the place, especially into the birth canal. These methods have worked for me in my over-20 years of practice.

I also firmly remind the RN circulator to perform a generous vaginal cleanse with povidone-iodine, in addition to the usual intravenous prophylaxis, before hysterectomy.
Luis Leyva Jr, MD
Miami, Florida

Mixed feelings
My first reaction to this Editorial was: Is this a solution in search of a problem? That is to say, how much of a clinical problem is endometritis after CD? Are we really treating the proposed problem, and does treatment affect long-term outcomes?

Upon reflection, I have concluded that vaginal cleansing pre-CD does intuitively make sense. What sways me in this direction is that the practice is simple, easy, and inexpensive. Since we typically have the patient positioned for Foley catheter insertion, performing vaginal cleansing as we put in the Foley would be easy. If vaginal cleansing were to be done, I definitely would be in favor of doing such practice liberally—for all CDs to make vaginal cleansing part of the “routine.”

Keep in mind that we are still chasing a problem of little clinical significance.

The biggest accomplishment has been to get everyone to give antibiotics preoperatively rather than after cutting the umbilical cord. We knew that this was best practice as early as the late 1980s/early 1990s, and I have been fighting this battle ever since. Believe it or not, there are still a few holdouts.
George H. Davis, DO
Johnson City, Tennessee

Would vaginal cleansing benefit all women in labor?
Vaginal cleansing before CD reminds me of my residency days when all women having hysterectomies were admitted early and given povidone-iodine (Betadine) douches the evening before surgery (unless an iodine allergy was present).

While reading your Editorial, I had several thoughts and questions. 1) Since vaginal cleansing seems to benefit CD patients, might it not benefit all laboring patients? 2) Is the timing of vaginal cleansing critical? 3) Should we do vaginal cleansing on all laboring patients if timing is not critical?

I plan to bring up the topic of vaginal cleansing for CD with my colleagues at our next department meeting, since it seems like such a simple, logical, inexpensive, and beneficial thing to do.
Douglas G. Tolley, MD
Yuba City, California

An early study on using povidone-iodine gel before CD
When I was a chief resident at Kings County Hospital in 1973, we had a very high rate of post-CD endometritis. I conducted a small study on the use of povidone-iodine gel in the last month of pregnancy. Before commencing, we confirmed that the gel did not interfere with diagnosing ruptured membranes.

Obstetric service patients were randomly divided into “A” and “B” groups. The A patients were asked to use povidone-iodine gel at night for the last 2 weeks before their estimated due date. When admitted in labor, they were asked to confirm its use. When a resident diagnosed post-CD endometritis, we kept track of which group the patient was in and whether or not that patient had used povidone-iodine. Approximately 100 infected patients were evaluated from each group.

As it turned out, there were about 3 times the number of infections among the patients who did not use povidone-iodine than among those who said they used it. It did not seem to matter how many times povidone-iodine was used. The “As” who did not use povidone-iodine had results similar to the “Bs.”

It was many years ago, and the study design was crude. However, it does seem to support the suggestion for vaginal cleansing.
Steve Ross, MD
Port Jefferson, New York

Two different ideas about the vaginal biome
This Editorial is timely in that Dr. Dominguez-Bello and colleagues recently published an article in Nature Medicine titled, “Partial restoration of the microbiota of cesarean-born infants via vaginal microbial transfer.”¹ Dr. Dominguez-Bello is one of the founders of the idea of “vaginal seeding,” or using the natural biome of the vagina on a newborn immediately after CD by swabbing the baby with the bacteria from the vagina.

I find it interesting that there are two very different ideas about the biome at this time. Vaginal seeding is a new trend that a few patients have asked about during prenatal care. The jury is still out on seeding, but a larger study is currently underway at New York University. Of course, infection is one of the risks of seeding. I appreciate hearing both sides of the issue.
Deborah Herchelroath, DO
Harrisburg, Pennsylvania

Reference

Dr. Barbieri responds
I would like to thank our readers for taking the time from their busy schedules to write about their clinical experiences and current practices for reducing infectious complications following CD.

Dr. Kerr raises the important issue of the apparent contradictory finding of the beneficial impact of vaginal cleansing on endometritis without a beneficial effect on the overall rate of fever. In the trial reported by Starr,¹ fever was defined as a temperature above 38˚C at any time after CD and endometritis was defined as a temperature above 38.4˚C PLUS uterine tenderness occurring more than 24 hours after CD. Given these 2 definitions one can understand the differential effect of vaginal cleansing on fever versus endometritis.

Dr. Simmons raises the intriguing question of the impact of an iodine-containing surgical preparation on newborn thyroid function. There are few studies addressing this issue. One study reports a transient increase in thyroid-stimulating hormone (TSH) levels in a small percentage of newborns whose mothers received an iodine preparation.² Another study reports no effect of an iodine surgical preparation on newborn thyroid function indices.³

I agree with the guidance of Drs. Leyva and Davis that we can help prevent postcesarean endometritis by minimizing the number of cervical examinations, changing scrubs between deliveries, and by ensuring that an intravenous anti‑ biotic is given before skin incision.

Dr. Tolley wonders if all women should receive vaginal cleansing, regardless of delivery route. It is possible that such an approach would be effective and it deserves study. Given the lower rate of endometritis following vaginal delivery compared with CD, many more women having a vaginal delivery would need to be treated to prevent one case of endometritis. Dr. Ross mentions his experience with the benefit of outpatient vaginal cleansing in the 2 weeks prior to delivery. Many general surgeons are recommending that their patients shower with chlorhexidine the day before surgery in order to reduce the rate of postoperative infection. Short-term and long-term outpatient vaginal cleansing prior to delivery deserves additional study.

Dr. Herchelroath raises the possibility that vaginal cleansing will decrease the ability of the newborn to develop a normal microbiome because it may not be exposed to sufficient vaginal bacteria. This possibility certainly deserves additional study.

The questions and guidance of our readers were incredibly helpful and stimulating. Thank you for sharing your perspective.

References

“CELL-FREE DNA SCREENING FOR WOMEN AT LOW RISK FOR FETAL ANEUPLOIDY” MARY E. NORTON, MD (JANUARY 2016)

The price of cfDNA screening is dropping
I found Dr. Norton’s article on cell-free DNA (cfDNA) screening for women at low risk for fetal abnormalities to be enlightening and educational. The section addressing cost-effectiveness, however, was somewhat obsolete. The referenced study by Cuckle and colleagues,¹ which estimated the cost of cfDNA per case of Down syndrome in low-risk patients at $3.6 million, was published in 2013. With 4 major companies in the market, the cost/benefit ratio has been changing rapidly. At least one company has dropped the cost of the cfDNA test nearly 80% from 2015 to 2016, making the above reference irrelevant. Recently, Ariosa dropped the price of their Harmony cfDNA test to just $119 in our area, regardless of a patient’s insurance or poverty level. This is significantly less than the cost of performing an early screen and is being welcomed by my patients even after substantial counseling on the test’s limitations in the low-risk population. Natera, another laboratory with a similar test, offers a low-cost option. However, patients must provide proof that their income is below a specified level.

Guidelines from the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) likely will have a hard time keeping up with the cost-effectiveness of noninvasive prenatal testing, as the price continues to be dynamic.
Samuel Wolf, DO
Panama City, Florida

Reference

“DOES THE DISCONTINUATION OF MENOPAUSAL HORMONE THERAPY AFFECT A WOMAN’S CARDIOVASCULAR RISK?”
ANDREW M. KAUNITZ, MD; JOANN E. MANSON, MD, DRPH; AND CYNTHIA A. STUENKEL, MD(EXAMINING THE EVIDENCE; DECEMBER 2015)

Disagrees with conclusion
In their expert commentary, Drs. Kaunitz, Manson, and Stuenkel state:

They support this claim by citing Heiss 2008.¹ In fact, however, the Women’s Health Initiative (WHI) data show opposite to their statement: In the WHI, all-cause mortality was increased among the women who were assigned to estrogen-progestin therapy (EPT) relative to those who were assigned to placebo within the 3 years of EPT cessation (hazard ratio [HR], 1.15; 95% confidence interval [CI], 0.95–1.39). More importantly, mortality was significantly increased among women who were originally assigned to EPT relative to those who were assigned to placebo and were at least 80% adherent with intervention (HR, 1.53; 95% CI, 1.04–2.24). Thus, the statement by Drs. Kaunitz, Manson, and Stuenkel is incorrect.

In addition to the WHI studies, data are available from at least 2 other randomized controlled trials addressing the issue of HT withdrawal. In the Heart and Estrogen/progestin Replacement Study (HERS) II,² the unblinded 2.7-year follow-up to the HERS trial, women originally assigned to EPT had a 3.3-fold higher rate of ventricular arrhythmia requiring resuscitation than women assigned to placebo (HR, 3.30; 95% CI, 1.08–10.10). During the first 6 months of posttrial follow-up of the Women’s Estrogen for Stroke Trial (WEST),³ there were 3 fatal strokes and 18 nonfatal strokes among the women originally randomized to estradiol therapy; there were 9 strokes (1 fatal and 8 nonfatal) among the women originally assigned to placebo (HR, 2.3; 95% CI, 1.1–5.0; P = .03).

In our study we detected that women who stopped HT, compared with women who continued HT, had a 2.3-fold (95% CI, 2.12–2.50) greater risk of cardiac death within the first post-HT year and a 1.3-fold (95% CI, 1.21–1.31) greater risk of cardiac death more than 1 year after stopping HT.⁴ In addition, women who stopped HT, compared with women who continuedHT, had a 2.5-fold (95% CI, 2.28–2.77) greater risk of dying from stroke within the first post-HT year and a 1.3-fold (95% CI, 1.19–1.31) greater risk of dying from stroke more than 1 year after stopping HT. We believe that these data substantially further our understanding of the posttrial data from WHI, as well as HERS and WEST. Thus, cumulative data support that HT withdrawal potentially has detrimental implications for women. In total, the data are highly informative when counseling women regarding use or discontinuation of HT.
Tomi Mikkola, MD
Helsinki, Finland

References

Drs. Kaunitz, Manson, and Stuenkel respond
We thank Dr. Mikkola for his response to our commentary, but we do not agree with his interpretation of the WHI reports or our conclusions. As we originally stated, the WHI trial of estrogen-only therapy (ET) and EPT provides an opportunity to observe outcomes in the largest randomized controlled trial of HT in healthy postmenopausal women. Our commentary was based on the most recent, 13-year follow-up of the WHI trials,¹ and we are confident in the accuracy of our presentation of the results.

As the debate apparently focuses on the safety of stopping HT, we wish to reiterate, for those who may not be familiar with the data, that, in the ET trial, all-cause mortality declined (although not significantly) after stopping ET, as summarized here:

 Similarly, in the EPT trial, as the following findings indicate, stopping HT did not increase all-cause mortality:

Again, these findings from the largest randomized trial of HT in healthy postmenopausal women are adequate for us to conclude that stopping HT does not elevate risk of mortality. Among all women participating in the WHI HT trials, HRs for coronary heart disease, pulmonary embolism, stroke, and cardiovascular disease mortality likewise were lower (better) after stopping treatment than during the intervention phase. The results for these outcomes in younger women followed similar patterns but, due to smaller numbers of events, could not be tested formally for differences in time trends.

Moreover, the data Dr. Mikkola cites from analyses conducted 3 years postcessation² reflected a borderline increased risk of cancer mortality that emerged in the EPT trial after stopping treatment. This clearly was related to the prolonged effects of EPT on breast cancer and other cancers, given the known latency period for cancer, and was not observed in the ET trial postcessation. The risk elevation in the EPT trial became attenuated with longer follow-up and, as of 13 years, the HRs for cancer mortality were 1.07 (0.93–1.23) in the EPT trial and 0.95 (0.81–1.13) in the ET trial.

It is interesting that Dr. Mikkola now inculcates his interpretation of his findings³ with those from secondary prevention trials such as the Heart and Estrogen/progestin Replacement Study and the Women’s Estrogen for Stroke Trial, neither of which was included as corroborative evidence in the discussion section of his originally published manuscript, and neither of which is considered applicable to healthy postmenopausal women taking HT for treatment of menopausal symptoms. Based on these findings, we do not recommend that clinicians counsel women that stopping HT increases their risk of cardiovascular or overall mortality. Thank you for the opportunity to clarify the evidence and our position.

References

“SHOULD YOU ADOPT THE PRACTICE OF VAGINAL CLEANSING WITH POVIDONE-IODINE PRIOR TO CESAREAN DELIVERY?”
ROBERT L. BARBIERI, MD (EDITORIAL; JANUARY 2016)
In his January 2016 Editorial, Editor in Chief Robert L. Barbieri, MD, presented evidence supporting the practice of vaginal cleansing with povidone-iodine prior to cesarean delivery (CD) to prevent postoperative endometritis. He then asked readers if they would consider adopting such a practice. More than 250 readers weighed in through the Quick Poll at obgmanagement.com, and many readers sent in letters with follow-up questions and comments on controlling bacterial contamination, vaginal seeding, etc. Here are some of the letters, along with Dr. Barbieri’s response and the Quick Poll results.

A contradiction in definitions?
There seems to be a contradiction in definitions. The second sentence of the article defines endometritis as the presence of fever plus low abdominal tenderness. However, the studies presented state that vaginal cleansing pre-CD decreased endometritis but did not decrease postpartum fever. Is this not a discrepancy?
Nancy Kerr, MD, MPH
Albuquerque, New Mexico

A question about povidone-iodine
Have any studies been done on newborn iodine levels after vaginal cleansing with povidone-iodine prior to CD?
G. Millard Simmons Jr, MD
Hilton Head, Bluffton, South Carolina

Additional tips for controlling bacterial contamination
Dr. Barbieri’s editorial on vaginal cleansing prior to CD is eye opening. I have a few additional suggestions to control bacterial contamination.

First, I examine my patients in labor as few times as necessary, and I ask the nurses (RNs) not to place their fingers in the patient’s vagina while she is pushing. I remove the Foley catheter when I feel progress (descent of fetal head) is being achieved. In addition, physicians as well as RNs should consider changing their scrubs between deliveries, as I believe that bacterial contamination is splattered all over the place, especially into the birth canal. These methods have worked for me in my over-20 years of practice.

I also firmly remind the RN circulator to perform a generous vaginal cleanse with povidone-iodine, in addition to the usual intravenous prophylaxis, before hysterectomy.
Luis Leyva Jr, MD
Miami, Florida

Mixed feelings
My first reaction to this Editorial was: Is this a solution in search of a problem? That is to say, how much of a clinical problem is endometritis after CD? Are we really treating the proposed problem, and does treatment affect long-term outcomes?

Upon reflection, I have concluded that vaginal cleansing pre-CD does intuitively make sense. What sways me in this direction is that the practice is simple, easy, and inexpensive. Since we typically have the patient positioned for Foley catheter insertion, performing vaginal cleansing as we put in the Foley would be easy. If vaginal cleansing were to be done, I definitely would be in favor of doing such practice liberally—for all CDs to make vaginal cleansing part of the “routine.”

Keep in mind that we are still chasing a problem of little clinical significance.

The biggest accomplishment has been to get everyone to give antibiotics preoperatively rather than after cutting the umbilical cord. We knew that this was best practice as early as the late 1980s/early 1990s, and I have been fighting this battle ever since. Believe it or not, there are still a few holdouts.
George H. Davis, DO
Johnson City, Tennessee

Would vaginal cleansing benefit all women in labor?
Vaginal cleansing before CD reminds me of my residency days when all women having hysterectomies were admitted early and given povidone-iodine (Betadine) douches the evening before surgery (unless an iodine allergy was present).

While reading your Editorial, I had several thoughts and questions. 1) Since vaginal cleansing seems to benefit CD patients, might it not benefit all laboring patients? 2) Is the timing of vaginal cleansing critical? 3) Should we do vaginal cleansing on all laboring patients if timing is not critical?

I plan to bring up the topic of vaginal cleansing for CD with my colleagues at our next department meeting, since it seems like such a simple, logical, inexpensive, and beneficial thing to do.
Douglas G. Tolley, MD
Yuba City, California

An early study on using povidone-iodine gel before CD
When I was a chief resident at Kings County Hospital in 1973, we had a very high rate of post-CD endometritis. I conducted a small study on the use of povidone-iodine gel in the last month of pregnancy. Before commencing, we confirmed that the gel did not interfere with diagnosing ruptured membranes.

Obstetric service patients were randomly divided into “A” and “B” groups. The A patients were asked to use povidone-iodine gel at night for the last 2 weeks before their estimated due date. When admitted in labor, they were asked to confirm its use. When a resident diagnosed post-CD endometritis, we kept track of which group the patient was in and whether or not that patient had used povidone-iodine. Approximately 100 infected patients were evaluated from each group.

As it turned out, there were about 3 times the number of infections among the patients who did not use povidone-iodine than among those who said they used it. It did not seem to matter how many times povidone-iodine was used. The “As” who did not use povidone-iodine had results similar to the “Bs.”

It was many years ago, and the study design was crude. However, it does seem to support the suggestion for vaginal cleansing.
Steve Ross, MD
Port Jefferson, New York

Two different ideas about the vaginal biome
This Editorial is timely in that Dr. Dominguez-Bello and colleagues recently published an article in Nature Medicine titled, “Partial restoration of the microbiota of cesarean-born infants via vaginal microbial transfer.”¹ Dr. Dominguez-Bello is one of the founders of the idea of “vaginal seeding,” or using the natural biome of the vagina on a newborn immediately after CD by swabbing the baby with the bacteria from the vagina.

I find it interesting that there are two very different ideas about the biome at this time. Vaginal seeding is a new trend that a few patients have asked about during prenatal care. The jury is still out on seeding, but a larger study is currently underway at New York University. Of course, infection is one of the risks of seeding. I appreciate hearing both sides of the issue.
Deborah Herchelroath, DO
Harrisburg, Pennsylvania

Reference

Dr. Barbieri responds
I would like to thank our readers for taking the time from their busy schedules to write about their clinical experiences and current practices for reducing infectious complications following CD.

Dr. Kerr raises the important issue of the apparent contradictory finding of the beneficial impact of vaginal cleansing on endometritis without a beneficial effect on the overall rate of fever. In the trial reported by Starr,¹ fever was defined as a temperature above 38˚C at any time after CD and endometritis was defined as a temperature above 38.4˚C PLUS uterine tenderness occurring more than 24 hours after CD. Given these 2 definitions one can understand the differential effect of vaginal cleansing on fever versus endometritis.

Dr. Simmons raises the intriguing question of the impact of an iodine-containing surgical preparation on newborn thyroid function. There are few studies addressing this issue. One study reports a transient increase in thyroid-stimulating hormone (TSH) levels in a small percentage of newborns whose mothers received an iodine preparation.² Another study reports no effect of an iodine surgical preparation on newborn thyroid function indices.³

I agree with the guidance of Drs. Leyva and Davis that we can help prevent postcesarean endometritis by minimizing the number of cervical examinations, changing scrubs between deliveries, and by ensuring that an intravenous anti‑ biotic is given before skin incision.

Dr. Tolley wonders if all women should receive vaginal cleansing, regardless of delivery route. It is possible that such an approach would be effective and it deserves study. Given the lower rate of endometritis following vaginal delivery compared with CD, many more women having a vaginal delivery would need to be treated to prevent one case of endometritis. Dr. Ross mentions his experience with the benefit of outpatient vaginal cleansing in the 2 weeks prior to delivery. Many general surgeons are recommending that their patients shower with chlorhexidine the day before surgery in order to reduce the rate of postoperative infection. Short-term and long-term outpatient vaginal cleansing prior to delivery deserves additional study.

Dr. Herchelroath raises the possibility that vaginal cleansing will decrease the ability of the newborn to develop a normal microbiome because it may not be exposed to sufficient vaginal bacteria. This possibility certainly deserves additional study.

The questions and guidance of our readers were incredibly helpful and stimulating. Thank you for sharing your perspective.

References

“CELL-FREE DNA SCREENING FOR WOMEN AT LOW RISK FOR FETAL ANEUPLOIDY” MARY E. NORTON, MD (JANUARY 2016)

The price of cfDNA screening is dropping
I found Dr. Norton’s article on cell-free DNA (cfDNA) screening for women at low risk for fetal abnormalities to be enlightening and educational. The section addressing cost-effectiveness, however, was somewhat obsolete. The referenced study by Cuckle and colleagues,¹ which estimated the cost of cfDNA per case of Down syndrome in low-risk patients at $3.6 million, was published in 2013. With 4 major companies in the market, the cost/benefit ratio has been changing rapidly. At least one company has dropped the cost of the cfDNA test nearly 80% from 2015 to 2016, making the above reference irrelevant. Recently, Ariosa dropped the price of their Harmony cfDNA test to just $119 in our area, regardless of a patient’s insurance or poverty level. This is significantly less than the cost of performing an early screen and is being welcomed by my patients even after substantial counseling on the test’s limitations in the low-risk population. Natera, another laboratory with a similar test, offers a low-cost option. However, patients must provide proof that their income is below a specified level.

Guidelines from the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) likely will have a hard time keeping up with the cost-effectiveness of noninvasive prenatal testing, as the price continues to be dynamic.
Samuel Wolf, DO
Panama City, Florida

Reference

“DOES THE DISCONTINUATION OF MENOPAUSAL HORMONE THERAPY AFFECT A WOMAN’S CARDIOVASCULAR RISK?”
ANDREW M. KAUNITZ, MD; JOANN E. MANSON, MD, DRPH; AND CYNTHIA A. STUENKEL, MD(EXAMINING THE EVIDENCE; DECEMBER 2015)

Disagrees with conclusion
In their expert commentary, Drs. Kaunitz, Manson, and Stuenkel state:

They support this claim by citing Heiss 2008.¹ In fact, however, the Women’s Health Initiative (WHI) data show opposite to their statement: In the WHI, all-cause mortality was increased among the women who were assigned to estrogen-progestin therapy (EPT) relative to those who were assigned to placebo within the 3 years of EPT cessation (hazard ratio [HR], 1.15; 95% confidence interval [CI], 0.95–1.39). More importantly, mortality was significantly increased among women who were originally assigned to EPT relative to those who were assigned to placebo and were at least 80% adherent with intervention (HR, 1.53; 95% CI, 1.04–2.24). Thus, the statement by Drs. Kaunitz, Manson, and Stuenkel is incorrect.

In addition to the WHI studies, data are available from at least 2 other randomized controlled trials addressing the issue of HT withdrawal. In the Heart and Estrogen/progestin Replacement Study (HERS) II,² the unblinded 2.7-year follow-up to the HERS trial, women originally assigned to EPT had a 3.3-fold higher rate of ventricular arrhythmia requiring resuscitation than women assigned to placebo (HR, 3.30; 95% CI, 1.08–10.10). During the first 6 months of posttrial follow-up of the Women’s Estrogen for Stroke Trial (WEST),³ there were 3 fatal strokes and 18 nonfatal strokes among the women originally randomized to estradiol therapy; there were 9 strokes (1 fatal and 8 nonfatal) among the women originally assigned to placebo (HR, 2.3; 95% CI, 1.1–5.0; P = .03).

In our study we detected that women who stopped HT, compared with women who continued HT, had a 2.3-fold (95% CI, 2.12–2.50) greater risk of cardiac death within the first post-HT year and a 1.3-fold (95% CI, 1.21–1.31) greater risk of cardiac death more than 1 year after stopping HT.⁴ In addition, women who stopped HT, compared with women who continuedHT, had a 2.5-fold (95% CI, 2.28–2.77) greater risk of dying from stroke within the first post-HT year and a 1.3-fold (95% CI, 1.19–1.31) greater risk of dying from stroke more than 1 year after stopping HT. We believe that these data substantially further our understanding of the posttrial data from WHI, as well as HERS and WEST. Thus, cumulative data support that HT withdrawal potentially has detrimental implications for women. In total, the data are highly informative when counseling women regarding use or discontinuation of HT.
Tomi Mikkola, MD
Helsinki, Finland

References

Drs. Kaunitz, Manson, and Stuenkel respond
We thank Dr. Mikkola for his response to our commentary, but we do not agree with his interpretation of the WHI reports or our conclusions. As we originally stated, the WHI trial of estrogen-only therapy (ET) and EPT provides an opportunity to observe outcomes in the largest randomized controlled trial of HT in healthy postmenopausal women. Our commentary was based on the most recent, 13-year follow-up of the WHI trials,¹ and we are confident in the accuracy of our presentation of the results.

As the debate apparently focuses on the safety of stopping HT, we wish to reiterate, for those who may not be familiar with the data, that, in the ET trial, all-cause mortality declined (although not significantly) after stopping ET, as summarized here:

 Similarly, in the EPT trial, as the following findings indicate, stopping HT did not increase all-cause mortality:

Again, these findings from the largest randomized trial of HT in healthy postmenopausal women are adequate for us to conclude that stopping HT does not elevate risk of mortality. Among all women participating in the WHI HT trials, HRs for coronary heart disease, pulmonary embolism, stroke, and cardiovascular disease mortality likewise were lower (better) after stopping treatment than during the intervention phase. The results for these outcomes in younger women followed similar patterns but, due to smaller numbers of events, could not be tested formally for differences in time trends.

Moreover, the data Dr. Mikkola cites from analyses conducted 3 years postcessation² reflected a borderline increased risk of cancer mortality that emerged in the EPT trial after stopping treatment. This clearly was related to the prolonged effects of EPT on breast cancer and other cancers, given the known latency period for cancer, and was not observed in the ET trial postcessation. The risk elevation in the EPT trial became attenuated with longer follow-up and, as of 13 years, the HRs for cancer mortality were 1.07 (0.93–1.23) in the EPT trial and 0.95 (0.81–1.13) in the ET trial.

It is interesting that Dr. Mikkola now inculcates his interpretation of his findings³ with those from secondary prevention trials such as the Heart and Estrogen/progestin Replacement Study and the Women’s Estrogen for Stroke Trial, neither of which was included as corroborative evidence in the discussion section of his originally published manuscript, and neither of which is considered applicable to healthy postmenopausal women taking HT for treatment of menopausal symptoms. Based on these findings, we do not recommend that clinicians counsel women that stopping HT increases their risk of cardiovascular or overall mortality. Thank you for the opportunity to clarify the evidence and our position.

References

“SHOULD YOU ADOPT THE PRACTICE OF VAGINAL CLEANSING WITH POVIDONE-IODINE PRIOR TO CESAREAN DELIVERY?”
ROBERT L. BARBIERI, MD (EDITORIAL; JANUARY 2016)
In his January 2016 Editorial, Editor in Chief Robert L. Barbieri, MD, presented evidence supporting the practice of vaginal cleansing with povidone-iodine prior to cesarean delivery (CD) to prevent postoperative endometritis. He then asked readers if they would consider adopting such a practice. More than 250 readers weighed in through the Quick Poll at obgmanagement.com, and many readers sent in letters with follow-up questions and comments on controlling bacterial contamination, vaginal seeding, etc. Here are some of the letters, along with Dr. Barbieri’s response and the Quick Poll results.

A contradiction in definitions?
There seems to be a contradiction in definitions. The second sentence of the article defines endometritis as the presence of fever plus low abdominal tenderness. However, the studies presented state that vaginal cleansing pre-CD decreased endometritis but did not decrease postpartum fever. Is this not a discrepancy?
Nancy Kerr, MD, MPH
Albuquerque, New Mexico

A question about povidone-iodine
Have any studies been done on newborn iodine levels after vaginal cleansing with povidone-iodine prior to CD?
G. Millard Simmons Jr, MD
Hilton Head, Bluffton, South Carolina

Additional tips for controlling bacterial contamination
Dr. Barbieri’s editorial on vaginal cleansing prior to CD is eye opening. I have a few additional suggestions to control bacterial contamination.

First, I examine my patients in labor as few times as necessary, and I ask the nurses (RNs) not to place their fingers in the patient’s vagina while she is pushing. I remove the Foley catheter when I feel progress (descent of fetal head) is being achieved. In addition, physicians as well as RNs should consider changing their scrubs between deliveries, as I believe that bacterial contamination is splattered all over the place, especially into the birth canal. These methods have worked for me in my over-20 years of practice.

I also firmly remind the RN circulator to perform a generous vaginal cleanse with povidone-iodine, in addition to the usual intravenous prophylaxis, before hysterectomy.
Luis Leyva Jr, MD
Miami, Florida

Mixed feelings
My first reaction to this Editorial was: Is this a solution in search of a problem? That is to say, how much of a clinical problem is endometritis after CD? Are we really treating the proposed problem, and does treatment affect long-term outcomes?

Upon reflection, I have concluded that vaginal cleansing pre-CD does intuitively make sense. What sways me in this direction is that the practice is simple, easy, and inexpensive. Since we typically have the patient positioned for Foley catheter insertion, performing vaginal cleansing as we put in the Foley would be easy. If vaginal cleansing were to be done, I definitely would be in favor of doing such practice liberally—for all CDs to make vaginal cleansing part of the “routine.”

Keep in mind that we are still chasing a problem of little clinical significance.

The biggest accomplishment has been to get everyone to give antibiotics preoperatively rather than after cutting the umbilical cord. We knew that this was best practice as early as the late 1980s/early 1990s, and I have been fighting this battle ever since. Believe it or not, there are still a few holdouts.
George H. Davis, DO
Johnson City, Tennessee

Would vaginal cleansing benefit all women in labor?
Vaginal cleansing before CD reminds me of my residency days when all women having hysterectomies were admitted early and given povidone-iodine (Betadine) douches the evening before surgery (unless an iodine allergy was present).

While reading your Editorial, I had several thoughts and questions. 1) Since vaginal cleansing seems to benefit CD patients, might it not benefit all laboring patients? 2) Is the timing of vaginal cleansing critical? 3) Should we do vaginal cleansing on all laboring patients if timing is not critical?

I plan to bring up the topic of vaginal cleansing for CD with my colleagues at our next department meeting, since it seems like such a simple, logical, inexpensive, and beneficial thing to do.
Douglas G. Tolley, MD
Yuba City, California

An early study on using povidone-iodine gel before CD
When I was a chief resident at Kings County Hospital in 1973, we had a very high rate of post-CD endometritis. I conducted a small study on the use of povidone-iodine gel in the last month of pregnancy. Before commencing, we confirmed that the gel did not interfere with diagnosing ruptured membranes.

Obstetric service patients were randomly divided into “A” and “B” groups. The A patients were asked to use povidone-iodine gel at night for the last 2 weeks before their estimated due date. When admitted in labor, they were asked to confirm its use. When a resident diagnosed post-CD endometritis, we kept track of which group the patient was in and whether or not that patient had used povidone-iodine. Approximately 100 infected patients were evaluated from each group.

As it turned out, there were about 3 times the number of infections among the patients who did not use povidone-iodine than among those who said they used it. It did not seem to matter how many times povidone-iodine was used. The “As” who did not use povidone-iodine had results similar to the “Bs.”

It was many years ago, and the study design was crude. However, it does seem to support the suggestion for vaginal cleansing.
Steve Ross, MD
Port Jefferson, New York

Two different ideas about the vaginal biome
This Editorial is timely in that Dr. Dominguez-Bello and colleagues recently published an article in Nature Medicine titled, “Partial restoration of the microbiota of cesarean-born infants via vaginal microbial transfer.”¹ Dr. Dominguez-Bello is one of the founders of the idea of “vaginal seeding,” or using the natural biome of the vagina on a newborn immediately after CD by swabbing the baby with the bacteria from the vagina.

I find it interesting that there are two very different ideas about the biome at this time. Vaginal seeding is a new trend that a few patients have asked about during prenatal care. The jury is still out on seeding, but a larger study is currently underway at New York University. Of course, infection is one of the risks of seeding. I appreciate hearing both sides of the issue.
Deborah Herchelroath, DO
Harrisburg, Pennsylvania

Reference

Dr. Barbieri responds
I would like to thank our readers for taking the time from their busy schedules to write about their clinical experiences and current practices for reducing infectious complications following CD.

Dr. Kerr raises the important issue of the apparent contradictory finding of the beneficial impact of vaginal cleansing on endometritis without a beneficial effect on the overall rate of fever. In the trial reported by Starr,¹ fever was defined as a temperature above 38˚C at any time after CD and endometritis was defined as a temperature above 38.4˚C PLUS uterine tenderness occurring more than 24 hours after CD. Given these 2 definitions one can understand the differential effect of vaginal cleansing on fever versus endometritis.

Dr. Simmons raises the intriguing question of the impact of an iodine-containing surgical preparation on newborn thyroid function. There are few studies addressing this issue. One study reports a transient increase in thyroid-stimulating hormone (TSH) levels in a small percentage of newborns whose mothers received an iodine preparation.² Another study reports no effect of an iodine surgical preparation on newborn thyroid function indices.³

I agree with the guidance of Drs. Leyva and Davis that we can help prevent postcesarean endometritis by minimizing the number of cervical examinations, changing scrubs between deliveries, and by ensuring that an intravenous anti‑ biotic is given before skin incision.

Dr. Tolley wonders if all women should receive vaginal cleansing, regardless of delivery route. It is possible that such an approach would be effective and it deserves study. Given the lower rate of endometritis following vaginal delivery compared with CD, many more women having a vaginal delivery would need to be treated to prevent one case of endometritis. Dr. Ross mentions his experience with the benefit of outpatient vaginal cleansing in the 2 weeks prior to delivery. Many general surgeons are recommending that their patients shower with chlorhexidine the day before surgery in order to reduce the rate of postoperative infection. Short-term and long-term outpatient vaginal cleansing prior to delivery deserves additional study.

Dr. Herchelroath raises the possibility that vaginal cleansing will decrease the ability of the newborn to develop a normal microbiome because it may not be exposed to sufficient vaginal bacteria. This possibility certainly deserves additional study.

The questions and guidance of our readers were incredibly helpful and stimulating. Thank you for sharing your perspective.

References

“CELL-FREE DNA SCREENING FOR WOMEN AT LOW RISK FOR FETAL ANEUPLOIDY” MARY E. NORTON, MD (JANUARY 2016)

The price of cfDNA screening is dropping
I found Dr. Norton’s article on cell-free DNA (cfDNA) screening for women at low risk for fetal abnormalities to be enlightening and educational. The section addressing cost-effectiveness, however, was somewhat obsolete. The referenced study by Cuckle and colleagues,¹ which estimated the cost of cfDNA per case of Down syndrome in low-risk patients at $3.6 million, was published in 2013. With 4 major companies in the market, the cost/benefit ratio has been changing rapidly. At least one company has dropped the cost of the cfDNA test nearly 80% from 2015 to 2016, making the above reference irrelevant. Recently, Ariosa dropped the price of their Harmony cfDNA test to just $119 in our area, regardless of a patient’s insurance or poverty level. This is significantly less than the cost of performing an early screen and is being welcomed by my patients even after substantial counseling on the test’s limitations in the low-risk population. Natera, another laboratory with a similar test, offers a low-cost option. However, patients must provide proof that their income is below a specified level.

Guidelines from the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) likely will have a hard time keeping up with the cost-effectiveness of noninvasive prenatal testing, as the price continues to be dynamic.
Samuel Wolf, DO
Panama City, Florida

Reference

“DOES THE DISCONTINUATION OF MENOPAUSAL HORMONE THERAPY AFFECT A WOMAN’S CARDIOVASCULAR RISK?”
ANDREW M. KAUNITZ, MD; JOANN E. MANSON, MD, DRPH; AND CYNTHIA A. STUENKEL, MD(EXAMINING THE EVIDENCE; DECEMBER 2015)

Disagrees with conclusion
In their expert commentary, Drs. Kaunitz, Manson, and Stuenkel state:

They support this claim by citing Heiss 2008.¹ In fact, however, the Women’s Health Initiative (WHI) data show opposite to their statement: In the WHI, all-cause mortality was increased among the women who were assigned to estrogen-progestin therapy (EPT) relative to those who were assigned to placebo within the 3 years of EPT cessation (hazard ratio [HR], 1.15; 95% confidence interval [CI], 0.95–1.39). More importantly, mortality was significantly increased among women who were originally assigned to EPT relative to those who were assigned to placebo and were at least 80% adherent with intervention (HR, 1.53; 95% CI, 1.04–2.24). Thus, the statement by Drs. Kaunitz, Manson, and Stuenkel is incorrect.

In addition to the WHI studies, data are available from at least 2 other randomized controlled trials addressing the issue of HT withdrawal. In the Heart and Estrogen/progestin Replacement Study (HERS) II,² the unblinded 2.7-year follow-up to the HERS trial, women originally assigned to EPT had a 3.3-fold higher rate of ventricular arrhythmia requiring resuscitation than women assigned to placebo (HR, 3.30; 95% CI, 1.08–10.10). During the first 6 months of posttrial follow-up of the Women’s Estrogen for Stroke Trial (WEST),³ there were 3 fatal strokes and 18 nonfatal strokes among the women originally randomized to estradiol therapy; there were 9 strokes (1 fatal and 8 nonfatal) among the women originally assigned to placebo (HR, 2.3; 95% CI, 1.1–5.0; P = .03).

In our study we detected that women who stopped HT, compared with women who continued HT, had a 2.3-fold (95% CI, 2.12–2.50) greater risk of cardiac death within the first post-HT year and a 1.3-fold (95% CI, 1.21–1.31) greater risk of cardiac death more than 1 year after stopping HT.⁴ In addition, women who stopped HT, compared with women who continuedHT, had a 2.5-fold (95% CI, 2.28–2.77) greater risk of dying from stroke within the first post-HT year and a 1.3-fold (95% CI, 1.19–1.31) greater risk of dying from stroke more than 1 year after stopping HT. We believe that these data substantially further our understanding of the posttrial data from WHI, as well as HERS and WEST. Thus, cumulative data support that HT withdrawal potentially has detrimental implications for women. In total, the data are highly informative when counseling women regarding use or discontinuation of HT.
Tomi Mikkola, MD
Helsinki, Finland

References

Drs. Kaunitz, Manson, and Stuenkel respond
We thank Dr. Mikkola for his response to our commentary, but we do not agree with his interpretation of the WHI reports or our conclusions. As we originally stated, the WHI trial of estrogen-only therapy (ET) and EPT provides an opportunity to observe outcomes in the largest randomized controlled trial of HT in healthy postmenopausal women. Our commentary was based on the most recent, 13-year follow-up of the WHI trials,¹ and we are confident in the accuracy of our presentation of the results.

As the debate apparently focuses on the safety of stopping HT, we wish to reiterate, for those who may not be familiar with the data, that, in the ET trial, all-cause mortality declined (although not significantly) after stopping ET, as summarized here:

 Similarly, in the EPT trial, as the following findings indicate, stopping HT did not increase all-cause mortality:

Again, these findings from the largest randomized trial of HT in healthy postmenopausal women are adequate for us to conclude that stopping HT does not elevate risk of mortality. Among all women participating in the WHI HT trials, HRs for coronary heart disease, pulmonary embolism, stroke, and cardiovascular disease mortality likewise were lower (better) after stopping treatment than during the intervention phase. The results for these outcomes in younger women followed similar patterns but, due to smaller numbers of events, could not be tested formally for differences in time trends.

Moreover, the data Dr. Mikkola cites from analyses conducted 3 years postcessation² reflected a borderline increased risk of cancer mortality that emerged in the EPT trial after stopping treatment. This clearly was related to the prolonged effects of EPT on breast cancer and other cancers, given the known latency period for cancer, and was not observed in the ET trial postcessation. The risk elevation in the EPT trial became attenuated with longer follow-up and, as of 13 years, the HRs for cancer mortality were 1.07 (0.93–1.23) in the EPT trial and 0.95 (0.81–1.13) in the ET trial.

It is interesting that Dr. Mikkola now inculcates his interpretation of his findings³ with those from secondary prevention trials such as the Heart and Estrogen/progestin Replacement Study and the Women’s Estrogen for Stroke Trial, neither of which was included as corroborative evidence in the discussion section of his originally published manuscript, and neither of which is considered applicable to healthy postmenopausal women taking HT for treatment of menopausal symptoms. Based on these findings, we do not recommend that clinicians counsel women that stopping HT increases their risk of cardiovascular or overall mortality. Thank you for the opportunity to clarify the evidence and our position.

References

Only recently has evidence emerged that challenges our long-held understanding of “normal” and “abnormal” labor. We now know there is a much wider range of normal labor progress in women who go on to have good labor outcomes. We have a new labor curve to guide us – one that shows us, for example, that active labor occurs most commonly after 6 cm dilation rather than 4 cm as we’d previously thought.

By appreciating this new labor paradigm, we can potentially have a significant impact on the cesarean rate in the United States. While our use of the older labor curve is not the only reason for the rise in cesarean deliveries over the last 30 years, it very likely has played a role. A study published in 2011 of more than 32,000 live births at a major academic hospital demonstrated that one of the most common reasons for primary cesarean is abnormal labor or arrest (Obstet Gynecol. 2011 Jul;118[1]:29-38).

Another study by the Consortium on Safe Labor – an analysis of labor and delivery information from more than 228,000 women across the United States – showed that half of the cesarean deliveries performed for dystocia in women undergoing labor induction were performed before 6 cm of cervical dilation and relatively soon after the previous cervical examination (Am J Obstet Gynecol. 2010 Oct; 203[4]: 326.e1–326.e10).

Our new labor paradigm brings to the forefront a host of new issues and questions about how we can best manage labor to optimize outcomes. In a way, recent discoveries about labor progress have highlighted a dearth of evidence and made “old” issues in labor management seem new and urgent.

As we strive to learn more, however, we are challenged to change our practices and behavior at the bedside with the evidence we currently have. By appreciating both the new labor curve and our current understanding of how labor induction, obesity, and other patient characteristics and clinical conditions can affect labor progress, we can expect that many women will simply progress much more slowly than was historically expected.

As long as we have indications of the well-being of the baby and the well-being of the mother, a slower but progressive labor in the first stage should not prompt us to intervene. We should no longer apply the standards of active-phase progress – standards that have traditionally driven our diagnoses of labor dystocia – until the patient has achieved 6 cm of dilation.

The labor curve that had shaped our thinking about normal and abnormal labor progress until recently was developed by Dr. Emanuel Friedman. Based on findings from a prospective cohort study of 500 nulliparous women, Dr. Friedman plotted labor progress with centimeters of cervical dilation on the Y-axis and time on the X-axis, and divided labor into several stages and phases. In this curve, the rate of change of cervical dilation over time started increasing significantly at 4 cm; this period of increasing slope defined the active phase of labor.

Abnormal labor progress in the active phase was then defined, based on the 95th percentile, as cervical dilation of less than 1.2 cm per hour for nulliparous women and less than 1.5 cm per hour for multiparous women. Based on Dr. Friedman’s work, a woman was deemed to be in active-phase arrest when she had no cervical changes for 2 hours or more while having adequate uterine contractions and cervical dilation of at least 4 cm. These concepts came to govern labor management.

The paradigm shifted when the Consortium on Safe Labor reported in 2010 on a retrospective cohort study of more than 62,000 women at 19 U.S. hospitals. The women had a singleton term gestation, spontaneous labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. In their analysis of labor and delivery information, Dr. Jun Zhang of the National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development and his colleagues accounted for the fact that the exact times of cervical change are unknown.

They used modern statistical methods and analytical tools that took into account the specific nature of cervical dilation data – that cervical measurements are interval-censored (we never know the exact time when a woman’s cervix changes) and that multiple exams of the cervix in the same patient are not independent (Obstet Gynecol. 2010 Dec;116[6]:1281-7).

The methodology used in the Consortium study accounted for both the interval-censored and repeated-measures nature of cervical dilation data. It thus addressed analytical flaws in the previous approach to labor data, which was purely descriptive of the exam findings and did not consider the nature of the data itself.

Under the new analysis and in the larger, contemporary population of patients, the period of increasing slope was found to occur most commonly after 6 cm, not 4 cm. The slowest 5% of nulliparous women had cervical dilation of 0.4 cm per hour (with the median at 1.9 cm per hour), compared with 1.2 cm per hour (with a median of 3.0 cm per hour) as in the Friedman data.

Dr. Zhang’s study showed us that labor may take more than 6 hours to progress from 4 to 5 cm dilation, and more than 3 hours to progress from 5 to 6 cm dilation – a rate of progress that is significantly slower than what Dr. Friedman had described. The new data showed us, moreover, that from 4 cm-6 cm dilation, nulliparous and multiparous women progressed similarly slowly. Beyond 6 cm, multiparous women dilated more rapidly, with a steeper acceleration phase than previously described.

A consensus statement published in 2014 by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) on “Safe Prevention of the Primary Cesarean Delivery” encourages use of the Consortium data to revisit the definition of labor dystocia. While the data “do not directly address an optimal duration for the diagnosis of active-phase protraction or labor arrest, [they] do suggest that neither should be diagnosed before 6 cm dilation” (Obstet Gynecol. 2014 Mar;123[3]:693-711).

The ACOG-SMFM statement makes a series of recommendations for managing the first and second stages of labor, based not only on the Consortium data but on a broader literature review. It recommends that if mother and fetus appear well, cesarean delivery for active-phase arrest in the first stage of labor be reserved for women of at least 6 cm of dilation with ruptured membranes who fail to progress despite 4 hours of adequate uterine activity, or at least 6 hours of oxytocin administration with inadequate uterine activity and no cervical change.

Regarding the latent phase of labor, the statement says that most women with a prolonged latent phase ultimately will enter the active phase with expectant management. It advises that a prolonged latent phase (for example, greater than 20 hours in nulliparous women and greater than 14 hours in multiparous women) should not be an isolated indication for cesarean delivery.

The consensus statement also recognizes recent data showing that women who undergo labor induction have an even slower “normal” course of labor, particularly a longer latent phase, than women who labor spontaneously. A retrospective cohort study of more than 5,000 women, for instance, found that before 6 cm, women whose labor is induced can spend up to 10 hours to achieve each 1 cm of dilation (Obstet Gynecol. 2012 Jun;119[6]:1113-8).

As long as maternal and fetal status are reassuring, the statement says, cesarean deliveries for failed induction of labor in the latent phase can be avoided by allowing longer durations of the latent phase (up to 24 hours) and by requiring that oxytocin be administered for 12-18 hours after membrane rupture before deeming induction a failure.

Each of these described recommendations were graded in the ACOG-SMFM consensus document as “strong” recommendations with “moderate quality evidence.”

Examining our standards

Moving forward, we must further develop and define our thresholds for identifying who will most benefit from a cesarean delivery. We have many specific aspects of labor management to address as well, such as the optimal timing of artificial membrane rupture and the safety and efficacy of different oxytocin protocols. We may also want to revisit recommendations for serial cervical assessment, possibly adjusting the intervals given our understanding of the new labor curve.

Under the new labor paradigm, moreover, we must think not only about the clinical decisions we make at the bedside, but about the decisions we make early in the labor management process.

The timing of admission is one such decision. A statement published in 2012 on “Preventing the First Cesarean Delivery” by ACOG, SMFM, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development advises us to avoid admittance of women during the early latent phase of labor (Obstet Gynecol. 2012 Nov;120[5]:1181-93).

It may even be advisable that we consider admittance at higher cervical dilation. A study published this year shows that women admitted at less than 6 cm of dilation had an increased risk of cesarean delivery, compared with women admitted at higher cervical dilation (Am J Perinatol. 2016 Jan;33[2]:188-94). We have more to learn, but certainly, given what we know now about labor progress and the start of active labor, the timing of admission is an important factor to consider.

The second stage of labor, defined as the interval from complete cervical dilation through delivery of the fetus, presents many questions as well. There is a paucity of quality published data concerning what is normal, how long the stage should last, and how we should manage it. Historically, we have been taught to allow 2 hours of pushing for nulliparous women and 1 hour for multiparous women, when epidural anesthesia has not been administered, and to add an additional hour when epidural is used.

The 2014 ACOG-SMFM consensus statement recommends extending each of these limits by an hour, if maternal and fetal conditions permit, so that we allow at least 3 hours of pushing for nulliparous women and at least 2 hours for multiparous women before diagnosing arrest of labor in the second stage. Longer durations may be appropriate with the use of epidural anesthesia and on an individualized basis.

At this time, it is unclear whether there is any absolute maximum length of time beyond which all women in the second stage of labor should undergo cesarean delivery. We also still do not know the optimal technique for managing maternal pushing during the second stage. Should women with an epidural push right away or should they allow for a period of spontaneous descent? Many of the high-quality studies reported thus far that compare delayed and immediate pushing have limited applicability to current practice because they involved now-obsolete midpelvic forceps deliveries. A large multicenter randomized trial currently underway should provide us with some answers.

Dr. Cahill is an associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University School of Medicine in St. Louis. She reported having no relevant financial disclosures.

Only recently has evidence emerged that challenges our long-held understanding of “normal” and “abnormal” labor. We now know there is a much wider range of normal labor progress in women who go on to have good labor outcomes. We have a new labor curve to guide us – one that shows us, for example, that active labor occurs most commonly after 6 cm dilation rather than 4 cm as we’d previously thought.

By appreciating this new labor paradigm, we can potentially have a significant impact on the cesarean rate in the United States. While our use of the older labor curve is not the only reason for the rise in cesarean deliveries over the last 30 years, it very likely has played a role. A study published in 2011 of more than 32,000 live births at a major academic hospital demonstrated that one of the most common reasons for primary cesarean is abnormal labor or arrest (Obstet Gynecol. 2011 Jul;118[1]:29-38).

Another study by the Consortium on Safe Labor – an analysis of labor and delivery information from more than 228,000 women across the United States – showed that half of the cesarean deliveries performed for dystocia in women undergoing labor induction were performed before 6 cm of cervical dilation and relatively soon after the previous cervical examination (Am J Obstet Gynecol. 2010 Oct; 203[4]: 326.e1–326.e10).

Our new labor paradigm brings to the forefront a host of new issues and questions about how we can best manage labor to optimize outcomes. In a way, recent discoveries about labor progress have highlighted a dearth of evidence and made “old” issues in labor management seem new and urgent.

As we strive to learn more, however, we are challenged to change our practices and behavior at the bedside with the evidence we currently have. By appreciating both the new labor curve and our current understanding of how labor induction, obesity, and other patient characteristics and clinical conditions can affect labor progress, we can expect that many women will simply progress much more slowly than was historically expected.

As long as we have indications of the well-being of the baby and the well-being of the mother, a slower but progressive labor in the first stage should not prompt us to intervene. We should no longer apply the standards of active-phase progress – standards that have traditionally driven our diagnoses of labor dystocia – until the patient has achieved 6 cm of dilation.

The labor curve that had shaped our thinking about normal and abnormal labor progress until recently was developed by Dr. Emanuel Friedman. Based on findings from a prospective cohort study of 500 nulliparous women, Dr. Friedman plotted labor progress with centimeters of cervical dilation on the Y-axis and time on the X-axis, and divided labor into several stages and phases. In this curve, the rate of change of cervical dilation over time started increasing significantly at 4 cm; this period of increasing slope defined the active phase of labor.

Abnormal labor progress in the active phase was then defined, based on the 95th percentile, as cervical dilation of less than 1.2 cm per hour for nulliparous women and less than 1.5 cm per hour for multiparous women. Based on Dr. Friedman’s work, a woman was deemed to be in active-phase arrest when she had no cervical changes for 2 hours or more while having adequate uterine contractions and cervical dilation of at least 4 cm. These concepts came to govern labor management.

The paradigm shifted when the Consortium on Safe Labor reported in 2010 on a retrospective cohort study of more than 62,000 women at 19 U.S. hospitals. The women had a singleton term gestation, spontaneous labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. In their analysis of labor and delivery information, Dr. Jun Zhang of the National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development and his colleagues accounted for the fact that the exact times of cervical change are unknown.

They used modern statistical methods and analytical tools that took into account the specific nature of cervical dilation data – that cervical measurements are interval-censored (we never know the exact time when a woman’s cervix changes) and that multiple exams of the cervix in the same patient are not independent (Obstet Gynecol. 2010 Dec;116[6]:1281-7).

The methodology used in the Consortium study accounted for both the interval-censored and repeated-measures nature of cervical dilation data. It thus addressed analytical flaws in the previous approach to labor data, which was purely descriptive of the exam findings and did not consider the nature of the data itself.

Under the new analysis and in the larger, contemporary population of patients, the period of increasing slope was found to occur most commonly after 6 cm, not 4 cm. The slowest 5% of nulliparous women had cervical dilation of 0.4 cm per hour (with the median at 1.9 cm per hour), compared with 1.2 cm per hour (with a median of 3.0 cm per hour) as in the Friedman data.

Dr. Zhang’s study showed us that labor may take more than 6 hours to progress from 4 to 5 cm dilation, and more than 3 hours to progress from 5 to 6 cm dilation – a rate of progress that is significantly slower than what Dr. Friedman had described. The new data showed us, moreover, that from 4 cm-6 cm dilation, nulliparous and multiparous women progressed similarly slowly. Beyond 6 cm, multiparous women dilated more rapidly, with a steeper acceleration phase than previously described.

A consensus statement published in 2014 by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) on “Safe Prevention of the Primary Cesarean Delivery” encourages use of the Consortium data to revisit the definition of labor dystocia. While the data “do not directly address an optimal duration for the diagnosis of active-phase protraction or labor arrest, [they] do suggest that neither should be diagnosed before 6 cm dilation” (Obstet Gynecol. 2014 Mar;123[3]:693-711).

The ACOG-SMFM statement makes a series of recommendations for managing the first and second stages of labor, based not only on the Consortium data but on a broader literature review. It recommends that if mother and fetus appear well, cesarean delivery for active-phase arrest in the first stage of labor be reserved for women of at least 6 cm of dilation with ruptured membranes who fail to progress despite 4 hours of adequate uterine activity, or at least 6 hours of oxytocin administration with inadequate uterine activity and no cervical change.

Regarding the latent phase of labor, the statement says that most women with a prolonged latent phase ultimately will enter the active phase with expectant management. It advises that a prolonged latent phase (for example, greater than 20 hours in nulliparous women and greater than 14 hours in multiparous women) should not be an isolated indication for cesarean delivery.

The consensus statement also recognizes recent data showing that women who undergo labor induction have an even slower “normal” course of labor, particularly a longer latent phase, than women who labor spontaneously. A retrospective cohort study of more than 5,000 women, for instance, found that before 6 cm, women whose labor is induced can spend up to 10 hours to achieve each 1 cm of dilation (Obstet Gynecol. 2012 Jun;119[6]:1113-8).

As long as maternal and fetal status are reassuring, the statement says, cesarean deliveries for failed induction of labor in the latent phase can be avoided by allowing longer durations of the latent phase (up to 24 hours) and by requiring that oxytocin be administered for 12-18 hours after membrane rupture before deeming induction a failure.

Each of these described recommendations were graded in the ACOG-SMFM consensus document as “strong” recommendations with “moderate quality evidence.”

Examining our standards

Moving forward, we must further develop and define our thresholds for identifying who will most benefit from a cesarean delivery. We have many specific aspects of labor management to address as well, such as the optimal timing of artificial membrane rupture and the safety and efficacy of different oxytocin protocols. We may also want to revisit recommendations for serial cervical assessment, possibly adjusting the intervals given our understanding of the new labor curve.

Under the new labor paradigm, moreover, we must think not only about the clinical decisions we make at the bedside, but about the decisions we make early in the labor management process.

The timing of admission is one such decision. A statement published in 2012 on “Preventing the First Cesarean Delivery” by ACOG, SMFM, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development advises us to avoid admittance of women during the early latent phase of labor (Obstet Gynecol. 2012 Nov;120[5]:1181-93).

It may even be advisable that we consider admittance at higher cervical dilation. A study published this year shows that women admitted at less than 6 cm of dilation had an increased risk of cesarean delivery, compared with women admitted at higher cervical dilation (Am J Perinatol. 2016 Jan;33[2]:188-94). We have more to learn, but certainly, given what we know now about labor progress and the start of active labor, the timing of admission is an important factor to consider.

The second stage of labor, defined as the interval from complete cervical dilation through delivery of the fetus, presents many questions as well. There is a paucity of quality published data concerning what is normal, how long the stage should last, and how we should manage it. Historically, we have been taught to allow 2 hours of pushing for nulliparous women and 1 hour for multiparous women, when epidural anesthesia has not been administered, and to add an additional hour when epidural is used.

The 2014 ACOG-SMFM consensus statement recommends extending each of these limits by an hour, if maternal and fetal conditions permit, so that we allow at least 3 hours of pushing for nulliparous women and at least 2 hours for multiparous women before diagnosing arrest of labor in the second stage. Longer durations may be appropriate with the use of epidural anesthesia and on an individualized basis.

At this time, it is unclear whether there is any absolute maximum length of time beyond which all women in the second stage of labor should undergo cesarean delivery. We also still do not know the optimal technique for managing maternal pushing during the second stage. Should women with an epidural push right away or should they allow for a period of spontaneous descent? Many of the high-quality studies reported thus far that compare delayed and immediate pushing have limited applicability to current practice because they involved now-obsolete midpelvic forceps deliveries. A large multicenter randomized trial currently underway should provide us with some answers.

Dr. Cahill is an associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University School of Medicine in St. Louis. She reported having no relevant financial disclosures.

Only recently has evidence emerged that challenges our long-held understanding of “normal” and “abnormal” labor. We now know there is a much wider range of normal labor progress in women who go on to have good labor outcomes. We have a new labor curve to guide us – one that shows us, for example, that active labor occurs most commonly after 6 cm dilation rather than 4 cm as we’d previously thought.

By appreciating this new labor paradigm, we can potentially have a significant impact on the cesarean rate in the United States. While our use of the older labor curve is not the only reason for the rise in cesarean deliveries over the last 30 years, it very likely has played a role. A study published in 2011 of more than 32,000 live births at a major academic hospital demonstrated that one of the most common reasons for primary cesarean is abnormal labor or arrest (Obstet Gynecol. 2011 Jul;118[1]:29-38).

Another study by the Consortium on Safe Labor – an analysis of labor and delivery information from more than 228,000 women across the United States – showed that half of the cesarean deliveries performed for dystocia in women undergoing labor induction were performed before 6 cm of cervical dilation and relatively soon after the previous cervical examination (Am J Obstet Gynecol. 2010 Oct; 203[4]: 326.e1–326.e10).

Our new labor paradigm brings to the forefront a host of new issues and questions about how we can best manage labor to optimize outcomes. In a way, recent discoveries about labor progress have highlighted a dearth of evidence and made “old” issues in labor management seem new and urgent.

As we strive to learn more, however, we are challenged to change our practices and behavior at the bedside with the evidence we currently have. By appreciating both the new labor curve and our current understanding of how labor induction, obesity, and other patient characteristics and clinical conditions can affect labor progress, we can expect that many women will simply progress much more slowly than was historically expected.

As long as we have indications of the well-being of the baby and the well-being of the mother, a slower but progressive labor in the first stage should not prompt us to intervene. We should no longer apply the standards of active-phase progress – standards that have traditionally driven our diagnoses of labor dystocia – until the patient has achieved 6 cm of dilation.

The labor curve that had shaped our thinking about normal and abnormal labor progress until recently was developed by Dr. Emanuel Friedman. Based on findings from a prospective cohort study of 500 nulliparous women, Dr. Friedman plotted labor progress with centimeters of cervical dilation on the Y-axis and time on the X-axis, and divided labor into several stages and phases. In this curve, the rate of change of cervical dilation over time started increasing significantly at 4 cm; this period of increasing slope defined the active phase of labor.

Abnormal labor progress in the active phase was then defined, based on the 95th percentile, as cervical dilation of less than 1.2 cm per hour for nulliparous women and less than 1.5 cm per hour for multiparous women. Based on Dr. Friedman’s work, a woman was deemed to be in active-phase arrest when she had no cervical changes for 2 hours or more while having adequate uterine contractions and cervical dilation of at least 4 cm. These concepts came to govern labor management.

The paradigm shifted when the Consortium on Safe Labor reported in 2010 on a retrospective cohort study of more than 62,000 women at 19 U.S. hospitals. The women had a singleton term gestation, spontaneous labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. In their analysis of labor and delivery information, Dr. Jun Zhang of the National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development and his colleagues accounted for the fact that the exact times of cervical change are unknown.

They used modern statistical methods and analytical tools that took into account the specific nature of cervical dilation data – that cervical measurements are interval-censored (we never know the exact time when a woman’s cervix changes) and that multiple exams of the cervix in the same patient are not independent (Obstet Gynecol. 2010 Dec;116[6]:1281-7).

The methodology used in the Consortium study accounted for both the interval-censored and repeated-measures nature of cervical dilation data. It thus addressed analytical flaws in the previous approach to labor data, which was purely descriptive of the exam findings and did not consider the nature of the data itself.

Under the new analysis and in the larger, contemporary population of patients, the period of increasing slope was found to occur most commonly after 6 cm, not 4 cm. The slowest 5% of nulliparous women had cervical dilation of 0.4 cm per hour (with the median at 1.9 cm per hour), compared with 1.2 cm per hour (with a median of 3.0 cm per hour) as in the Friedman data.

Dr. Zhang’s study showed us that labor may take more than 6 hours to progress from 4 to 5 cm dilation, and more than 3 hours to progress from 5 to 6 cm dilation – a rate of progress that is significantly slower than what Dr. Friedman had described. The new data showed us, moreover, that from 4 cm-6 cm dilation, nulliparous and multiparous women progressed similarly slowly. Beyond 6 cm, multiparous women dilated more rapidly, with a steeper acceleration phase than previously described.

A consensus statement published in 2014 by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) on “Safe Prevention of the Primary Cesarean Delivery” encourages use of the Consortium data to revisit the definition of labor dystocia. While the data “do not directly address an optimal duration for the diagnosis of active-phase protraction or labor arrest, [they] do suggest that neither should be diagnosed before 6 cm dilation” (Obstet Gynecol. 2014 Mar;123[3]:693-711).

The ACOG-SMFM statement makes a series of recommendations for managing the first and second stages of labor, based not only on the Consortium data but on a broader literature review. It recommends that if mother and fetus appear well, cesarean delivery for active-phase arrest in the first stage of labor be reserved for women of at least 6 cm of dilation with ruptured membranes who fail to progress despite 4 hours of adequate uterine activity, or at least 6 hours of oxytocin administration with inadequate uterine activity and no cervical change.

Regarding the latent phase of labor, the statement says that most women with a prolonged latent phase ultimately will enter the active phase with expectant management. It advises that a prolonged latent phase (for example, greater than 20 hours in nulliparous women and greater than 14 hours in multiparous women) should not be an isolated indication for cesarean delivery.

The consensus statement also recognizes recent data showing that women who undergo labor induction have an even slower “normal” course of labor, particularly a longer latent phase, than women who labor spontaneously. A retrospective cohort study of more than 5,000 women, for instance, found that before 6 cm, women whose labor is induced can spend up to 10 hours to achieve each 1 cm of dilation (Obstet Gynecol. 2012 Jun;119[6]:1113-8).

As long as maternal and fetal status are reassuring, the statement says, cesarean deliveries for failed induction of labor in the latent phase can be avoided by allowing longer durations of the latent phase (up to 24 hours) and by requiring that oxytocin be administered for 12-18 hours after membrane rupture before deeming induction a failure.

Each of these described recommendations were graded in the ACOG-SMFM consensus document as “strong” recommendations with “moderate quality evidence.”

Examining our standards

Moving forward, we must further develop and define our thresholds for identifying who will most benefit from a cesarean delivery. We have many specific aspects of labor management to address as well, such as the optimal timing of artificial membrane rupture and the safety and efficacy of different oxytocin protocols. We may also want to revisit recommendations for serial cervical assessment, possibly adjusting the intervals given our understanding of the new labor curve.

Under the new labor paradigm, moreover, we must think not only about the clinical decisions we make at the bedside, but about the decisions we make early in the labor management process.

The timing of admission is one such decision. A statement published in 2012 on “Preventing the First Cesarean Delivery” by ACOG, SMFM, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development advises us to avoid admittance of women during the early latent phase of labor (Obstet Gynecol. 2012 Nov;120[5]:1181-93).

It may even be advisable that we consider admittance at higher cervical dilation. A study published this year shows that women admitted at less than 6 cm of dilation had an increased risk of cesarean delivery, compared with women admitted at higher cervical dilation (Am J Perinatol. 2016 Jan;33[2]:188-94). We have more to learn, but certainly, given what we know now about labor progress and the start of active labor, the timing of admission is an important factor to consider.

The second stage of labor, defined as the interval from complete cervical dilation through delivery of the fetus, presents many questions as well. There is a paucity of quality published data concerning what is normal, how long the stage should last, and how we should manage it. Historically, we have been taught to allow 2 hours of pushing for nulliparous women and 1 hour for multiparous women, when epidural anesthesia has not been administered, and to add an additional hour when epidural is used.

The 2014 ACOG-SMFM consensus statement recommends extending each of these limits by an hour, if maternal and fetal conditions permit, so that we allow at least 3 hours of pushing for nulliparous women and at least 2 hours for multiparous women before diagnosing arrest of labor in the second stage. Longer durations may be appropriate with the use of epidural anesthesia and on an individualized basis.

At this time, it is unclear whether there is any absolute maximum length of time beyond which all women in the second stage of labor should undergo cesarean delivery. We also still do not know the optimal technique for managing maternal pushing during the second stage. Should women with an epidural push right away or should they allow for a period of spontaneous descent? Many of the high-quality studies reported thus far that compare delayed and immediate pushing have limited applicability to current practice because they involved now-obsolete midpelvic forceps deliveries. A large multicenter randomized trial currently underway should provide us with some answers.

Dr. Cahill is an associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University School of Medicine in St. Louis. She reported having no relevant financial disclosures.

Over the last 50 years, we have witnessed some incredible advancements that have vastly improved maternal and fetal outcomes, even in the face of the most complex obstetrical dilemmas. As our practice and the research continues to evolve, it is increasingly important that we carefully review our practice standards to ensure that every woman and her baby receives the most up-to-date medical care.

This month’s Master Class highlights a critical area of obstetrics where the convergence of technology, clinical observation, and research stimulated a change in practice guidelines: the use of the labor curve to monitor normal versus abnormal labor. Until quite recently, ob.gyns. had based labor criteria on the “Friedman Curve,” first established in the mid-1950s, and supported by other smaller and less comprehensive studies. This work was adopted by the American College of Obstetricians and Gynecologists.

For more than half a century, we used these parameters to determine if a woman had entered active-phase arrest, and to make the very important decision of whether to perform a cesarean section. However, work in the early 2000s strongly suggested that the old criteria no longer applied to the full course of labor in contemporary patients (Am J Obstet Gynecol. 2002 Oct;187[4]:824-8). A 2010 comprehensive study showed that we needed to consider a new approach to labor management (Am J Obstet Gynecol. 2010 Oct;203[4]:326.e1-326.e10).

It may seem incredible that it took such a long time to update our thinking about what constitutes normal versus abnormal labor progression. However, we must keep in mind that many studies supported the original labor curve, and advanced tools to assess fetal health during labor were just being developed. The first commercially available fetal heart rate monitor would not be produced until 1968, and debates about the utility of these devices would continue into the early 1990s.

Additionally, our patient population has changed. As we have discussed in previous columns, the incidence and severity of other chronic conditions, such as diabetes and obesity, has increased significantly and deeply impacted labor progression.

Just as technology has advanced and our patients’ needs have changed, so, too, must our practice standards. We have invited Dr. Alison G. Cahill, associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University, St. Louis, to discuss the importance and implications of the new labor curve.

Dr. Reece, who specializes in maternal-fetal medicine, is vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. Dr. Reece said he had no relevant financial disclosures. He is the medical editor of this column. Contact him at [email protected].

Over the last 50 years, we have witnessed some incredible advancements that have vastly improved maternal and fetal outcomes, even in the face of the most complex obstetrical dilemmas. As our practice and the research continues to evolve, it is increasingly important that we carefully review our practice standards to ensure that every woman and her baby receives the most up-to-date medical care.

This month’s Master Class highlights a critical area of obstetrics where the convergence of technology, clinical observation, and research stimulated a change in practice guidelines: the use of the labor curve to monitor normal versus abnormal labor. Until quite recently, ob.gyns. had based labor criteria on the “Friedman Curve,” first established in the mid-1950s, and supported by other smaller and less comprehensive studies. This work was adopted by the American College of Obstetricians and Gynecologists.

For more than half a century, we used these parameters to determine if a woman had entered active-phase arrest, and to make the very important decision of whether to perform a cesarean section. However, work in the early 2000s strongly suggested that the old criteria no longer applied to the full course of labor in contemporary patients (Am J Obstet Gynecol. 2002 Oct;187[4]:824-8). A 2010 comprehensive study showed that we needed to consider a new approach to labor management (Am J Obstet Gynecol. 2010 Oct;203[4]:326.e1-326.e10).

It may seem incredible that it took such a long time to update our thinking about what constitutes normal versus abnormal labor progression. However, we must keep in mind that many studies supported the original labor curve, and advanced tools to assess fetal health during labor were just being developed. The first commercially available fetal heart rate monitor would not be produced until 1968, and debates about the utility of these devices would continue into the early 1990s.

Additionally, our patient population has changed. As we have discussed in previous columns, the incidence and severity of other chronic conditions, such as diabetes and obesity, has increased significantly and deeply impacted labor progression.

Just as technology has advanced and our patients’ needs have changed, so, too, must our practice standards. We have invited Dr. Alison G. Cahill, associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University, St. Louis, to discuss the importance and implications of the new labor curve.

Dr. Reece, who specializes in maternal-fetal medicine, is vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. Dr. Reece said he had no relevant financial disclosures. He is the medical editor of this column. Contact him at [email protected].

Over the last 50 years, we have witnessed some incredible advancements that have vastly improved maternal and fetal outcomes, even in the face of the most complex obstetrical dilemmas. As our practice and the research continues to evolve, it is increasingly important that we carefully review our practice standards to ensure that every woman and her baby receives the most up-to-date medical care.

This month’s Master Class highlights a critical area of obstetrics where the convergence of technology, clinical observation, and research stimulated a change in practice guidelines: the use of the labor curve to monitor normal versus abnormal labor. Until quite recently, ob.gyns. had based labor criteria on the “Friedman Curve,” first established in the mid-1950s, and supported by other smaller and less comprehensive studies. This work was adopted by the American College of Obstetricians and Gynecologists.

For more than half a century, we used these parameters to determine if a woman had entered active-phase arrest, and to make the very important decision of whether to perform a cesarean section. However, work in the early 2000s strongly suggested that the old criteria no longer applied to the full course of labor in contemporary patients (Am J Obstet Gynecol. 2002 Oct;187[4]:824-8). A 2010 comprehensive study showed that we needed to consider a new approach to labor management (Am J Obstet Gynecol. 2010 Oct;203[4]:326.e1-326.e10).

It may seem incredible that it took such a long time to update our thinking about what constitutes normal versus abnormal labor progression. However, we must keep in mind that many studies supported the original labor curve, and advanced tools to assess fetal health during labor were just being developed. The first commercially available fetal heart rate monitor would not be produced until 1968, and debates about the utility of these devices would continue into the early 1990s.

Additionally, our patient population has changed. As we have discussed in previous columns, the incidence and severity of other chronic conditions, such as diabetes and obesity, has increased significantly and deeply impacted labor progression.

Just as technology has advanced and our patients’ needs have changed, so, too, must our practice standards. We have invited Dr. Alison G. Cahill, associate professor and chief of the division of maternal-fetal medicine in the department of obstetrics and gynecology at Washington University, St. Louis, to discuss the importance and implications of the new labor curve.

Dr. Reece, who specializes in maternal-fetal medicine, is vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. Dr. Reece said he had no relevant financial disclosures. He is the medical editor of this column. Contact him at [email protected].