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MMR Shot Not Linked to Autism, According to U.K. Study
Children with autism spectrum disorder had no greater immune response to the measles virus or the measles component of the measles, mumps, and rubella vaccine than did children without the disorder in a large case-control study
Writing in the Archives of Disease of Childhood, British researchers said that their community sample study of 250 children aged 10–12 years is the largest to date to fail to demonstrate any association between MMR vaccination and autism spectrum disorder (ASD) “using well-validated techniques.”
Concern about the possible connection has led to lower MMR vaccination rates, from 92% in 1995–1996 to 80% in 2004, according to UK Health Protection Agency data cited by the researchers (Arch. Dis. Child. 2007 Feb. 5 [Epub doi:10.1136/adc.2007.122937]).
Led by Dr. Gillian Baird of Guy's and St. Thomas' National Health Service Trust in London, the researchers said uptake of the second MMR vaccination was lower in the children who had autism or autism spectrum disorder than in the control population without autism (29% vs. 50%).
Children with special education needs but not autism spectrum disorder had lower vaccination rates than normal developing children.
These differences in uptake between groups “may reflect parental concern about vaccination following a diagnosis of developmental abnormality,” the researchers wrote.
Four of the authors listed conflicts of interests relating to lawsuits against manufacturers of the MMR vaccines, including Dr. Baird, who has served as an expert witness.
The researchers drew their subjects from a cohort of 56,946 children born between July 1, 1990, and Dec. 31, 1991, from the South Thames region of England.
After screening for autism spectrum disorders and special educational needs, the researchers identified 98 cases of autism spectrum disorders. The cases were compared to 52 control children who had special educational needs but no diagnosis of autism, along with 90 control children with typical development.
The researchers analyzed blood from the subjects to determine whether they had persistent measles infections or abnormally high measles antibodies.
They found no differences in the distribution of measles antibodies or virus in the children with autism spectrum disorder or the controls, regardless of whether children had received one or both of the MMR vaccinations.
There also was no sign of altered persisting immunological response in autism spectrum disorder cases, in those with or without a history of regression.
Regression of language was defined as a loss of at least five words used communicately during a 3-month period, or, in those who had not achieved the five-word stage, “a reported regression of words or skills in social communicative or play behavior.”
Authors of a case series published in 2000 had described a condition referred to as “autism enterocolitis,” postulated to be associated with the MMR vaccine and regression in autism.
Researchers in the current study found no evidence of increased enterocolitis in the autism spectrum disorder group with regression.
Only one child in the study had “possible enterocolitis,” and this child was from a control group
The researchers said their study is strong because of its size, the geographic definition of its sample, good vaccination histories, and a diagnostic procedure that allowed researchers to identify a dose-response relationship between autism symptoms and antibody levels.
However, Dr. Baird and his fellow investigators noted that the control population was not randomly selected, and might therefore have been biased.
The children's parents were informed it was a study about MMR vaccination.
Children with autism spectrum disorder had no greater immune response to the measles virus or the measles component of the measles, mumps, and rubella vaccine than did children without the disorder in a large case-control study
Writing in the Archives of Disease of Childhood, British researchers said that their community sample study of 250 children aged 10–12 years is the largest to date to fail to demonstrate any association between MMR vaccination and autism spectrum disorder (ASD) “using well-validated techniques.”
Concern about the possible connection has led to lower MMR vaccination rates, from 92% in 1995–1996 to 80% in 2004, according to UK Health Protection Agency data cited by the researchers (Arch. Dis. Child. 2007 Feb. 5 [Epub doi:10.1136/adc.2007.122937]).
Led by Dr. Gillian Baird of Guy's and St. Thomas' National Health Service Trust in London, the researchers said uptake of the second MMR vaccination was lower in the children who had autism or autism spectrum disorder than in the control population without autism (29% vs. 50%).
Children with special education needs but not autism spectrum disorder had lower vaccination rates than normal developing children.
These differences in uptake between groups “may reflect parental concern about vaccination following a diagnosis of developmental abnormality,” the researchers wrote.
Four of the authors listed conflicts of interests relating to lawsuits against manufacturers of the MMR vaccines, including Dr. Baird, who has served as an expert witness.
The researchers drew their subjects from a cohort of 56,946 children born between July 1, 1990, and Dec. 31, 1991, from the South Thames region of England.
After screening for autism spectrum disorders and special educational needs, the researchers identified 98 cases of autism spectrum disorders. The cases were compared to 52 control children who had special educational needs but no diagnosis of autism, along with 90 control children with typical development.
The researchers analyzed blood from the subjects to determine whether they had persistent measles infections or abnormally high measles antibodies.
They found no differences in the distribution of measles antibodies or virus in the children with autism spectrum disorder or the controls, regardless of whether children had received one or both of the MMR vaccinations.
There also was no sign of altered persisting immunological response in autism spectrum disorder cases, in those with or without a history of regression.
Regression of language was defined as a loss of at least five words used communicately during a 3-month period, or, in those who had not achieved the five-word stage, “a reported regression of words or skills in social communicative or play behavior.”
Authors of a case series published in 2000 had described a condition referred to as “autism enterocolitis,” postulated to be associated with the MMR vaccine and regression in autism.
Researchers in the current study found no evidence of increased enterocolitis in the autism spectrum disorder group with regression.
Only one child in the study had “possible enterocolitis,” and this child was from a control group
The researchers said their study is strong because of its size, the geographic definition of its sample, good vaccination histories, and a diagnostic procedure that allowed researchers to identify a dose-response relationship between autism symptoms and antibody levels.
However, Dr. Baird and his fellow investigators noted that the control population was not randomly selected, and might therefore have been biased.
The children's parents were informed it was a study about MMR vaccination.
Children with autism spectrum disorder had no greater immune response to the measles virus or the measles component of the measles, mumps, and rubella vaccine than did children without the disorder in a large case-control study
Writing in the Archives of Disease of Childhood, British researchers said that their community sample study of 250 children aged 10–12 years is the largest to date to fail to demonstrate any association between MMR vaccination and autism spectrum disorder (ASD) “using well-validated techniques.”
Concern about the possible connection has led to lower MMR vaccination rates, from 92% in 1995–1996 to 80% in 2004, according to UK Health Protection Agency data cited by the researchers (Arch. Dis. Child. 2007 Feb. 5 [Epub doi:10.1136/adc.2007.122937]).
Led by Dr. Gillian Baird of Guy's and St. Thomas' National Health Service Trust in London, the researchers said uptake of the second MMR vaccination was lower in the children who had autism or autism spectrum disorder than in the control population without autism (29% vs. 50%).
Children with special education needs but not autism spectrum disorder had lower vaccination rates than normal developing children.
These differences in uptake between groups “may reflect parental concern about vaccination following a diagnosis of developmental abnormality,” the researchers wrote.
Four of the authors listed conflicts of interests relating to lawsuits against manufacturers of the MMR vaccines, including Dr. Baird, who has served as an expert witness.
The researchers drew their subjects from a cohort of 56,946 children born between July 1, 1990, and Dec. 31, 1991, from the South Thames region of England.
After screening for autism spectrum disorders and special educational needs, the researchers identified 98 cases of autism spectrum disorders. The cases were compared to 52 control children who had special educational needs but no diagnosis of autism, along with 90 control children with typical development.
The researchers analyzed blood from the subjects to determine whether they had persistent measles infections or abnormally high measles antibodies.
They found no differences in the distribution of measles antibodies or virus in the children with autism spectrum disorder or the controls, regardless of whether children had received one or both of the MMR vaccinations.
There also was no sign of altered persisting immunological response in autism spectrum disorder cases, in those with or without a history of regression.
Regression of language was defined as a loss of at least five words used communicately during a 3-month period, or, in those who had not achieved the five-word stage, “a reported regression of words or skills in social communicative or play behavior.”
Authors of a case series published in 2000 had described a condition referred to as “autism enterocolitis,” postulated to be associated with the MMR vaccine and regression in autism.
Researchers in the current study found no evidence of increased enterocolitis in the autism spectrum disorder group with regression.
Only one child in the study had “possible enterocolitis,” and this child was from a control group
The researchers said their study is strong because of its size, the geographic definition of its sample, good vaccination histories, and a diagnostic procedure that allowed researchers to identify a dose-response relationship between autism symptoms and antibody levels.
However, Dr. Baird and his fellow investigators noted that the control population was not randomly selected, and might therefore have been biased.
The children's parents were informed it was a study about MMR vaccination.
Elective C-Section Linked To Respiratory Morbidity
Elective cesarian section increases by up to fourfold the risk of respiratory morbidity in babies delivered at 37–39 weeks of gestation, compared with babies delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates. “Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality.”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery. Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors wrote. (BMJ 2008;336:85–7).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation). The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with vaginal delivery. At 39 weeks, the odds ratio was 2.4, but this increase in risk was not significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Elective cesarian section increases by up to fourfold the risk of respiratory morbidity in babies delivered at 37–39 weeks of gestation, compared with babies delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates. “Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality.”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery. Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors wrote. (BMJ 2008;336:85–7).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation). The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with vaginal delivery. At 39 weeks, the odds ratio was 2.4, but this increase in risk was not significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Elective cesarian section increases by up to fourfold the risk of respiratory morbidity in babies delivered at 37–39 weeks of gestation, compared with babies delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates. “Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality.”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery. Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors wrote. (BMJ 2008;336:85–7).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation). The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with vaginal delivery. At 39 weeks, the odds ratio was 2.4, but this increase in risk was not significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Study Links Food Additives to Hyperactive Behavior in Children
Children given a beverage containing certain mixtures of food colors and the preservative sodium benzoate showed significantly increased hyperactivity scores in a British randomized, controlled, cross-over study.
Findings of the study, which included 153 3-year-olds and 144 8- and 9-year-old children selected from the general population, support previous research suggesting that certain food additives can exacerbate hyperactive behaviors such as inattention, impulsivity, and overactivity.
Investigators in the current study said their findings suggest that the policy makers review the use of food additives because of their potential negative effect on education (Lancet 2007 Sept. 6 [Epub doi:10.1016/S0140-6736(07)61306-3
“This study provides evidence of deleterious effects of (additives) on children's behaviour with data from a whole population sample,” wrote the researchers, led by Jim Stevenson, Ph.D., of the University of Southampton's School of Psychology.
“These findings show that adverse effects are not just seen in children with extreme hyperactivity (i.e., ADHD), but can also be seen in the general population and across the range of severities of hyperactivity.”
The study was funded by a grant from the United Kingdom's Food Standards Agency.
Children given a beverage containing certain mixtures of food colors and the preservative sodium benzoate showed significantly increased hyperactivity scores in a British randomized, controlled, cross-over study.
Findings of the study, which included 153 3-year-olds and 144 8- and 9-year-old children selected from the general population, support previous research suggesting that certain food additives can exacerbate hyperactive behaviors such as inattention, impulsivity, and overactivity.
Investigators in the current study said their findings suggest that the policy makers review the use of food additives because of their potential negative effect on education (Lancet 2007 Sept. 6 [Epub doi:10.1016/S0140-6736(07)61306-3
“This study provides evidence of deleterious effects of (additives) on children's behaviour with data from a whole population sample,” wrote the researchers, led by Jim Stevenson, Ph.D., of the University of Southampton's School of Psychology.
“These findings show that adverse effects are not just seen in children with extreme hyperactivity (i.e., ADHD), but can also be seen in the general population and across the range of severities of hyperactivity.”
The study was funded by a grant from the United Kingdom's Food Standards Agency.
Children given a beverage containing certain mixtures of food colors and the preservative sodium benzoate showed significantly increased hyperactivity scores in a British randomized, controlled, cross-over study.
Findings of the study, which included 153 3-year-olds and 144 8- and 9-year-old children selected from the general population, support previous research suggesting that certain food additives can exacerbate hyperactive behaviors such as inattention, impulsivity, and overactivity.
Investigators in the current study said their findings suggest that the policy makers review the use of food additives because of their potential negative effect on education (Lancet 2007 Sept. 6 [Epub doi:10.1016/S0140-6736(07)61306-3
“This study provides evidence of deleterious effects of (additives) on children's behaviour with data from a whole population sample,” wrote the researchers, led by Jim Stevenson, Ph.D., of the University of Southampton's School of Psychology.
“These findings show that adverse effects are not just seen in children with extreme hyperactivity (i.e., ADHD), but can also be seen in the general population and across the range of severities of hyperactivity.”
The study was funded by a grant from the United Kingdom's Food Standards Agency.
Elective C-Section Linked to Infant Respiratory Problems
Elective C-section increases by up to fourfold the risk of respiratory morbidity in babies who were delivered at 37–39 weeks of gestation, compared with babies who were delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote online in BMJ.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates.
“Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality,”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery.
Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors reported (doi:10.1136/bmj.39405.539282.BE).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining babies were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation).
The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with intended vaginal delivery.
At 39 weeks, the odds ratio was 2.4, but this increase in risk was not statistically significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Catecholamines are present in the fetus during normal vaginal delivery in response to the rupture of membranes and labor, a phenomenon that may decrease the secretion of fetal lung liquid, increase its absorption, and stimulate the release of surfactants.
Elective C-section increases by up to fourfold the risk of respiratory morbidity in babies who were delivered at 37–39 weeks of gestation, compared with babies who were delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote online in BMJ.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates.
“Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality,”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery.
Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors reported (doi:10.1136/bmj.39405.539282.BE).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining babies were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation).
The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with intended vaginal delivery.
At 39 weeks, the odds ratio was 2.4, but this increase in risk was not statistically significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Catecholamines are present in the fetus during normal vaginal delivery in response to the rupture of membranes and labor, a phenomenon that may decrease the secretion of fetal lung liquid, increase its absorption, and stimulate the release of surfactants.
Elective C-section increases by up to fourfold the risk of respiratory morbidity in babies who were delivered at 37–39 weeks of gestation, compared with babies who were delivered vaginally or by emergency C-section at the same gestational age.
That finding—from a Danish cohort study of 34,458 singleton deliveries—suggests that elective C-section should wait until after the 39th week, the study investigators wrote online in BMJ.
“Carrying out elective caesarean sections at greater gestational ages may, however, result in higher rates of intrapartum caesarean sections because some women would go into spontaneous labour (in our population, 25% of spontaneous intended vaginal deliveries started before 39 weeks' gestation),” wrote Anne Kirkeby Hansen of the Aarhus (Denmark) University Hospital and associates.
“Compared with elective caesarean sections, intrapartum caesarean sections may carry an increased risk of complications such as uterine rupture in women with previous caesarean section, infections, or even maternal mortality,”
The risk of respiratory morbidity (transitory tachypnea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) was increased in babies delivered by elective C-section at 37 weeks (odds ratio 3.9), 38 weeks (OR 3.0), and 39 weeks (OR 1.9), compared with newborns intended for vaginal delivery.
Risk was not increased at 40 weeks (OR 0.9).
The data were adjusted for factors such as smoking and parity, the study authors reported (doi:10.1136/bmj.39405.539282.BE).
The analysis included all liveborn singletons born without malformation between 37 and 41 weeks' gestation at one institution between 1998 and 2006.
In all, 2,687 liveborn babies were delivered by elective C-section and 2,877 were delivered by emergency C-section. The remaining babies were born vaginally.
A total of 1.8% of all babies had a respiratory problem, with 0.2% of them having serious respiratory morbidity (a condition requiring treatment for at least 3 days with continuous oxygen supplementation, nasal continuous positive airway pressure, or any period of mechanical ventilation).
The relative risk for serious respiratory morbidity was increased in those delivered by elective C-section at 37 weeks (OR 5.0) and 38 weeks (OR 4.2), compared with intended vaginal delivery.
At 39 weeks, the odds ratio was 2.4, but this increase in risk was not statistically significant.
The authors said hormones released during normal vaginal delivery may help prevent respiratory problems.
Catecholamines are present in the fetus during normal vaginal delivery in response to the rupture of membranes and labor, a phenomenon that may decrease the secretion of fetal lung liquid, increase its absorption, and stimulate the release of surfactants.
OCs May Offer Protection Against Some Cancers
Use of oral contraceptives is not associated with an overall increase in cancer, and it may provide a net public health benefit, reducing women's risk of developing the disease, according to a large British cohort study.
Researchers said the study of more than 1 million woman-years in the Royal College of General Practitioners oral contraceptive study indicates that the overall absolute reduction in risk of any cancer among those who have ever used oral contraceptives (OC) was 45 per 100,000 woman-years in the main data set. The benefit was greater among older women than younger, peaking at age 50–59 (90 per 100,000 woman-years) (BMJ 2007 Sept. 12 [Epub doi:10.1136/bmj.39289.649410.55]).
Researchers, led by Dr. Phillip C. Hannaford of the University of Aberdeen (Scotland), found the risk of all cancers was significantly lower among women who have used oral contraceptives, compared with those who never took them (adjusted relative risk 0.88). Statistically significant risk reductions were detected for OC users in cancers of the large bowel or rectum (adjusted relative risk 0.72), uterine body (0.58), ovaries (0.54), site unknown (0.64), and other (0.88).
Researchers detected a small but statistically insignificant increase in cancers of the lung, cervix, central nervous system, or pituitary for women who had ever taken oral contraceptives. There was no difference in breast cancer between the ever takers and never takers, although for main gynecologic cancers there was a reduced risk among the ever takers (adjusted relative risk 0.71). Median time of use was 44 months.
When compared with women who had never used OCs, however, women who had used them for more than 8 years had significantly increased risk: for all cancers (adjusted relative risk 1.22), cervix (2.73), and central nervous system or pituitary (5.51). Those same women, however, had a significantly reduced risk of ovarian cancer (0.38). “It is important to remember…,” the researchers emphasized, “that comparatively few women in our study used oral contraceptives for such durations, with less than a quarter of users being at this increased risk.”
While the findings should be good news for older women similar in age to those in this study, the researchers cautioned that the trends they found might not continue.
“Many women, especially those who used the first generation of oral contraceptives many years ago, are likely to be reassured by our results,” wrote the researchers. “Our findings might not, however, reflect the experience of women using oral contraceptives today, if currently available preparations have a different risk to earlier products, or if differences in patterns of usage (such as age at starting oral contraceptives or duration of use) materially affect cancer risk.”
They add: “These results suggest that, at least in this relatively healthy U.K. cohort, the cancer benefits associated with oral contraception outweigh the risks.”
The study enrolled 23,000 women taking oral contraceptives and 23,000 who had never used them over 14 months beginning in May 1968. The mean age at the time of recruitment was 29 years. All the women were married or in a stable relationship. Most were white.
The women were followed until they left the area of their recruiting doctor, the doctor left the study, they began receiving oral contraceptives from another source, they died, or they reached the end of the follow-up in 1996. A total of 26% of the women made it to the end of the follow-up in 1996.
Three-quarters of the original cohort, those whose doctors were still in the study, were flagged in the mid-1970s for National Health Service central registries in England and Scotland so subsequent cancers and deaths could be reported to the study, through December 2004.
The study also included a smaller set of data gathered while the subjects were under direct observation of their general practitioners until they were lost to follow-up, they developed their first relevant cancer, or the observation period ended in 1996.
In that smaller data set of more than 500,000 woman-years, researchers were unable to detect many of the statistical differences found in the larger cohort. However, they detected significantly reduced risk for oral contraceptive users of cancers of the uterine body (adjusted relative risk 0.47) and ovary (0.51).
Use of oral contraceptives is not associated with an overall increase in cancer, and it may provide a net public health benefit, reducing women's risk of developing the disease, according to a large British cohort study.
Researchers said the study of more than 1 million woman-years in the Royal College of General Practitioners oral contraceptive study indicates that the overall absolute reduction in risk of any cancer among those who have ever used oral contraceptives (OC) was 45 per 100,000 woman-years in the main data set. The benefit was greater among older women than younger, peaking at age 50–59 (90 per 100,000 woman-years) (BMJ 2007 Sept. 12 [Epub doi:10.1136/bmj.39289.649410.55]).
Researchers, led by Dr. Phillip C. Hannaford of the University of Aberdeen (Scotland), found the risk of all cancers was significantly lower among women who have used oral contraceptives, compared with those who never took them (adjusted relative risk 0.88). Statistically significant risk reductions were detected for OC users in cancers of the large bowel or rectum (adjusted relative risk 0.72), uterine body (0.58), ovaries (0.54), site unknown (0.64), and other (0.88).
Researchers detected a small but statistically insignificant increase in cancers of the lung, cervix, central nervous system, or pituitary for women who had ever taken oral contraceptives. There was no difference in breast cancer between the ever takers and never takers, although for main gynecologic cancers there was a reduced risk among the ever takers (adjusted relative risk 0.71). Median time of use was 44 months.
When compared with women who had never used OCs, however, women who had used them for more than 8 years had significantly increased risk: for all cancers (adjusted relative risk 1.22), cervix (2.73), and central nervous system or pituitary (5.51). Those same women, however, had a significantly reduced risk of ovarian cancer (0.38). “It is important to remember…,” the researchers emphasized, “that comparatively few women in our study used oral contraceptives for such durations, with less than a quarter of users being at this increased risk.”
While the findings should be good news for older women similar in age to those in this study, the researchers cautioned that the trends they found might not continue.
“Many women, especially those who used the first generation of oral contraceptives many years ago, are likely to be reassured by our results,” wrote the researchers. “Our findings might not, however, reflect the experience of women using oral contraceptives today, if currently available preparations have a different risk to earlier products, or if differences in patterns of usage (such as age at starting oral contraceptives or duration of use) materially affect cancer risk.”
They add: “These results suggest that, at least in this relatively healthy U.K. cohort, the cancer benefits associated with oral contraception outweigh the risks.”
The study enrolled 23,000 women taking oral contraceptives and 23,000 who had never used them over 14 months beginning in May 1968. The mean age at the time of recruitment was 29 years. All the women were married or in a stable relationship. Most were white.
The women were followed until they left the area of their recruiting doctor, the doctor left the study, they began receiving oral contraceptives from another source, they died, or they reached the end of the follow-up in 1996. A total of 26% of the women made it to the end of the follow-up in 1996.
Three-quarters of the original cohort, those whose doctors were still in the study, were flagged in the mid-1970s for National Health Service central registries in England and Scotland so subsequent cancers and deaths could be reported to the study, through December 2004.
The study also included a smaller set of data gathered while the subjects were under direct observation of their general practitioners until they were lost to follow-up, they developed their first relevant cancer, or the observation period ended in 1996.
In that smaller data set of more than 500,000 woman-years, researchers were unable to detect many of the statistical differences found in the larger cohort. However, they detected significantly reduced risk for oral contraceptive users of cancers of the uterine body (adjusted relative risk 0.47) and ovary (0.51).
Use of oral contraceptives is not associated with an overall increase in cancer, and it may provide a net public health benefit, reducing women's risk of developing the disease, according to a large British cohort study.
Researchers said the study of more than 1 million woman-years in the Royal College of General Practitioners oral contraceptive study indicates that the overall absolute reduction in risk of any cancer among those who have ever used oral contraceptives (OC) was 45 per 100,000 woman-years in the main data set. The benefit was greater among older women than younger, peaking at age 50–59 (90 per 100,000 woman-years) (BMJ 2007 Sept. 12 [Epub doi:10.1136/bmj.39289.649410.55]).
Researchers, led by Dr. Phillip C. Hannaford of the University of Aberdeen (Scotland), found the risk of all cancers was significantly lower among women who have used oral contraceptives, compared with those who never took them (adjusted relative risk 0.88). Statistically significant risk reductions were detected for OC users in cancers of the large bowel or rectum (adjusted relative risk 0.72), uterine body (0.58), ovaries (0.54), site unknown (0.64), and other (0.88).
Researchers detected a small but statistically insignificant increase in cancers of the lung, cervix, central nervous system, or pituitary for women who had ever taken oral contraceptives. There was no difference in breast cancer between the ever takers and never takers, although for main gynecologic cancers there was a reduced risk among the ever takers (adjusted relative risk 0.71). Median time of use was 44 months.
When compared with women who had never used OCs, however, women who had used them for more than 8 years had significantly increased risk: for all cancers (adjusted relative risk 1.22), cervix (2.73), and central nervous system or pituitary (5.51). Those same women, however, had a significantly reduced risk of ovarian cancer (0.38). “It is important to remember…,” the researchers emphasized, “that comparatively few women in our study used oral contraceptives for such durations, with less than a quarter of users being at this increased risk.”
While the findings should be good news for older women similar in age to those in this study, the researchers cautioned that the trends they found might not continue.
“Many women, especially those who used the first generation of oral contraceptives many years ago, are likely to be reassured by our results,” wrote the researchers. “Our findings might not, however, reflect the experience of women using oral contraceptives today, if currently available preparations have a different risk to earlier products, or if differences in patterns of usage (such as age at starting oral contraceptives or duration of use) materially affect cancer risk.”
They add: “These results suggest that, at least in this relatively healthy U.K. cohort, the cancer benefits associated with oral contraception outweigh the risks.”
The study enrolled 23,000 women taking oral contraceptives and 23,000 who had never used them over 14 months beginning in May 1968. The mean age at the time of recruitment was 29 years. All the women were married or in a stable relationship. Most were white.
The women were followed until they left the area of their recruiting doctor, the doctor left the study, they began receiving oral contraceptives from another source, they died, or they reached the end of the follow-up in 1996. A total of 26% of the women made it to the end of the follow-up in 1996.
Three-quarters of the original cohort, those whose doctors were still in the study, were flagged in the mid-1970s for National Health Service central registries in England and Scotland so subsequent cancers and deaths could be reported to the study, through December 2004.
The study also included a smaller set of data gathered while the subjects were under direct observation of their general practitioners until they were lost to follow-up, they developed their first relevant cancer, or the observation period ended in 1996.
In that smaller data set of more than 500,000 woman-years, researchers were unable to detect many of the statistical differences found in the larger cohort. However, they detected significantly reduced risk for oral contraceptive users of cancers of the uterine body (adjusted relative risk 0.47) and ovary (0.51).
China Reports on First Human Cases of Avian Flu in 6 Months
China has confirmed the first human cases of the highly pathogenic H5N1 avian influenza virus in 6 months, international public health officials have reported.
The two cases are a father and son in the Jiangsu province, according to the World Health Organization, citing the Chinese health ministry. One of the close contacts being observed by public health officials, the 52-year-old father became sick on Dec. 3, at which time he was admitted to the hospital. The Chinese national laboratory confirmed his infection as H5N1 in early December, WHO said.
His 24-year-old son died on Dec. 2, 2 weeks after developing symptoms. The national laboratory confirmed the son's infection as H5N1 on the day he died. Public health investigators have not traced any contact with birds by the two men, WHO said.
China has reported 27 human cases of H5N1—17 of which have been fatal—since its first reported case in 2003. Five cases, three of them fatal, have occurred this year, according to WHO.
In addition, WHO said, Indonesia has reported four cases of H5N1 since mid-October, all but one fatal. These cases included the following:
▸ A 5-year-old girl from Tangerang District, Banten Province, who died in the hospital on Oct. 22.
▸ A 3-year-old boy from Tangerang District who became sick on Oct. 14 but recovered.
▸ A 30-year-old woman from Tangerang District who died in the hospital on Nov. 3.
▸ A 31-year-old man from Bengkalis District, Riau Province, who died in the hospital on Nov. 6.
WHO said the three cases in Tangerang District occurred in neighborhoods or households that were close to dead poultry, whereas the final case involves an investigation into a swallow farm near the home of the patient who died.
Including the most recent cases, Indonesia's toll has been 113 human cases of H5N1, with 91 deaths. Of that number, 38 total cases (including 33 deaths) have occurred this year, WHO said.
In total, WHO said that 337 human cases of H5N1 have been reported since the first ones in 2003, 207 of which have been fatal. This year, 74 cases, 49 of them fatal, have been reported, according to WHO.
China has confirmed the first human cases of the highly pathogenic H5N1 avian influenza virus in 6 months, international public health officials have reported.
The two cases are a father and son in the Jiangsu province, according to the World Health Organization, citing the Chinese health ministry. One of the close contacts being observed by public health officials, the 52-year-old father became sick on Dec. 3, at which time he was admitted to the hospital. The Chinese national laboratory confirmed his infection as H5N1 in early December, WHO said.
His 24-year-old son died on Dec. 2, 2 weeks after developing symptoms. The national laboratory confirmed the son's infection as H5N1 on the day he died. Public health investigators have not traced any contact with birds by the two men, WHO said.
China has reported 27 human cases of H5N1—17 of which have been fatal—since its first reported case in 2003. Five cases, three of them fatal, have occurred this year, according to WHO.
In addition, WHO said, Indonesia has reported four cases of H5N1 since mid-October, all but one fatal. These cases included the following:
▸ A 5-year-old girl from Tangerang District, Banten Province, who died in the hospital on Oct. 22.
▸ A 3-year-old boy from Tangerang District who became sick on Oct. 14 but recovered.
▸ A 30-year-old woman from Tangerang District who died in the hospital on Nov. 3.
▸ A 31-year-old man from Bengkalis District, Riau Province, who died in the hospital on Nov. 6.
WHO said the three cases in Tangerang District occurred in neighborhoods or households that were close to dead poultry, whereas the final case involves an investigation into a swallow farm near the home of the patient who died.
Including the most recent cases, Indonesia's toll has been 113 human cases of H5N1, with 91 deaths. Of that number, 38 total cases (including 33 deaths) have occurred this year, WHO said.
In total, WHO said that 337 human cases of H5N1 have been reported since the first ones in 2003, 207 of which have been fatal. This year, 74 cases, 49 of them fatal, have been reported, according to WHO.
China has confirmed the first human cases of the highly pathogenic H5N1 avian influenza virus in 6 months, international public health officials have reported.
The two cases are a father and son in the Jiangsu province, according to the World Health Organization, citing the Chinese health ministry. One of the close contacts being observed by public health officials, the 52-year-old father became sick on Dec. 3, at which time he was admitted to the hospital. The Chinese national laboratory confirmed his infection as H5N1 in early December, WHO said.
His 24-year-old son died on Dec. 2, 2 weeks after developing symptoms. The national laboratory confirmed the son's infection as H5N1 on the day he died. Public health investigators have not traced any contact with birds by the two men, WHO said.
China has reported 27 human cases of H5N1—17 of which have been fatal—since its first reported case in 2003. Five cases, three of them fatal, have occurred this year, according to WHO.
In addition, WHO said, Indonesia has reported four cases of H5N1 since mid-October, all but one fatal. These cases included the following:
▸ A 5-year-old girl from Tangerang District, Banten Province, who died in the hospital on Oct. 22.
▸ A 3-year-old boy from Tangerang District who became sick on Oct. 14 but recovered.
▸ A 30-year-old woman from Tangerang District who died in the hospital on Nov. 3.
▸ A 31-year-old man from Bengkalis District, Riau Province, who died in the hospital on Nov. 6.
WHO said the three cases in Tangerang District occurred in neighborhoods or households that were close to dead poultry, whereas the final case involves an investigation into a swallow farm near the home of the patient who died.
Including the most recent cases, Indonesia's toll has been 113 human cases of H5N1, with 91 deaths. Of that number, 38 total cases (including 33 deaths) have occurred this year, WHO said.
In total, WHO said that 337 human cases of H5N1 have been reported since the first ones in 2003, 207 of which have been fatal. This year, 74 cases, 49 of them fatal, have been reported, according to WHO.
Preeclampsia, CVD Linked; Prevention Urged
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review.
“The underlying link between pre-eclampsia and cardiovascular disease is unclear. Although pre-eclampsia may initiate endothelial damage, it is thought to be more likely that pre-eclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women, British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention.”
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review.
“The underlying link between pre-eclampsia and cardiovascular disease is unclear. Although pre-eclampsia may initiate endothelial damage, it is thought to be more likely that pre-eclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women, British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention.”
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review.
“The underlying link between pre-eclampsia and cardiovascular disease is unclear. Although pre-eclampsia may initiate endothelial damage, it is thought to be more likely that pre-eclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women, British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention.”
Studies Link Preeclampsia, Cardiovascular Disease : The two disorders are thought to have a common pathogenesis that is rooted in shared risk markers.
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review published online in the British Medical Journal.
Meanwhile, an accompanying population-based prospective study in Norway suggests that cardiovascular risk factors are associated with a higher risk of preeclampsia.
“The underlying link between preeclampsia and cardiovascular disease is unclear. Although preeclampsia may initiate endothelial damage, it is thought to be more likely that preeclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary accompanying the two studies (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In the first study–a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women–British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years.
No increase in the risk of any cancer was found, including breast cancer, after 17 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention, especially as cardiovascular disease is largely preventable.”
They added, however, that the findings so far do not help physicians guide their primary prevention strategy. No evidence supports how to screen younger women for risk factors, and while recommending lifestyle change is good for all patients, such a recommendation “is not enough to change their behavior,” the authors wrote. “However, women might be more receptive if they have had a complicated pregnancy. Perhaps we could tailor the advice to women with newborns and young children,” they wrote.
The Norwegian study tracked 3,494 women who gave birth after participating in the Nord-Trøndelag health study to link cardiovascular risk factors and preeclampsia risk. The women were linked to diagnoses for preeclampsia through the Norway birth registry (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39366.416817.BE]).
After adjustment, the odds ratio for preeclampsia in women with a baseline systolic blood pressure greater than 130 mm Hg (highest fifth) was 7.3, compared with those with a systolic blood pressure less than 111 mm Hg (lowest fifth). Similarly, the odds ratio for women with a diastolic blood pressure greater than 78 mm Hg was 6.3, compared with those whose diastolic pressure was less than 64 mm Hg.
Women who were overweight or obese had a higher risk of preeclampsia than did women of normal weight, and the risk for preeclampsia rose with increasing waist circumference.
In addition, there was a weak association between pregnancy lipid levels in the clinically normal range and preeclampsia, and a stronger association with lipid levels above the normal range.
“We found that cardiovascular risk factors that were present years before pregnancy are associated with a risk of preeclampsia,” wrote Elisabeth Balstad Magnussen, a research fellow at the Norwegian University of Science and Technology, Trondheim, and associates. “This finding suggests that unfavourable cardiovascular and metabolic profiles may represent primary causes of preeclampsia and that these factors predispose both to preeclampsia and to subsequent cardiovascular disease. This does not, however, rule out the possibility that the pre-eclamptic process in itself may also contribute to cardiovascular risk.
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review published online in the British Medical Journal.
Meanwhile, an accompanying population-based prospective study in Norway suggests that cardiovascular risk factors are associated with a higher risk of preeclampsia.
“The underlying link between preeclampsia and cardiovascular disease is unclear. Although preeclampsia may initiate endothelial damage, it is thought to be more likely that preeclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary accompanying the two studies (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In the first study–a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women–British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years.
No increase in the risk of any cancer was found, including breast cancer, after 17 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention, especially as cardiovascular disease is largely preventable.”
They added, however, that the findings so far do not help physicians guide their primary prevention strategy. No evidence supports how to screen younger women for risk factors, and while recommending lifestyle change is good for all patients, such a recommendation “is not enough to change their behavior,” the authors wrote. “However, women might be more receptive if they have had a complicated pregnancy. Perhaps we could tailor the advice to women with newborns and young children,” they wrote.
The Norwegian study tracked 3,494 women who gave birth after participating in the Nord-Trøndelag health study to link cardiovascular risk factors and preeclampsia risk. The women were linked to diagnoses for preeclampsia through the Norway birth registry (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39366.416817.BE]).
After adjustment, the odds ratio for preeclampsia in women with a baseline systolic blood pressure greater than 130 mm Hg (highest fifth) was 7.3, compared with those with a systolic blood pressure less than 111 mm Hg (lowest fifth). Similarly, the odds ratio for women with a diastolic blood pressure greater than 78 mm Hg was 6.3, compared with those whose diastolic pressure was less than 64 mm Hg.
Women who were overweight or obese had a higher risk of preeclampsia than did women of normal weight, and the risk for preeclampsia rose with increasing waist circumference.
In addition, there was a weak association between pregnancy lipid levels in the clinically normal range and preeclampsia, and a stronger association with lipid levels above the normal range.
“We found that cardiovascular risk factors that were present years before pregnancy are associated with a risk of preeclampsia,” wrote Elisabeth Balstad Magnussen, a research fellow at the Norwegian University of Science and Technology, Trondheim, and associates. “This finding suggests that unfavourable cardiovascular and metabolic profiles may represent primary causes of preeclampsia and that these factors predispose both to preeclampsia and to subsequent cardiovascular disease. This does not, however, rule out the possibility that the pre-eclamptic process in itself may also contribute to cardiovascular risk.
Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review published online in the British Medical Journal.
Meanwhile, an accompanying population-based prospective study in Norway suggests that cardiovascular risk factors are associated with a higher risk of preeclampsia.
“The underlying link between preeclampsia and cardiovascular disease is unclear. Although preeclampsia may initiate endothelial damage, it is thought to be more likely that preeclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary accompanying the two studies (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In the first study–a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women–British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years.
No increase in the risk of any cancer was found, including breast cancer, after 17 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention, especially as cardiovascular disease is largely preventable.”
They added, however, that the findings so far do not help physicians guide their primary prevention strategy. No evidence supports how to screen younger women for risk factors, and while recommending lifestyle change is good for all patients, such a recommendation “is not enough to change their behavior,” the authors wrote. “However, women might be more receptive if they have had a complicated pregnancy. Perhaps we could tailor the advice to women with newborns and young children,” they wrote.
The Norwegian study tracked 3,494 women who gave birth after participating in the Nord-Trøndelag health study to link cardiovascular risk factors and preeclampsia risk. The women were linked to diagnoses for preeclampsia through the Norway birth registry (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39366.416817.BE]).
After adjustment, the odds ratio for preeclampsia in women with a baseline systolic blood pressure greater than 130 mm Hg (highest fifth) was 7.3, compared with those with a systolic blood pressure less than 111 mm Hg (lowest fifth). Similarly, the odds ratio for women with a diastolic blood pressure greater than 78 mm Hg was 6.3, compared with those whose diastolic pressure was less than 64 mm Hg.
Women who were overweight or obese had a higher risk of preeclampsia than did women of normal weight, and the risk for preeclampsia rose with increasing waist circumference.
In addition, there was a weak association between pregnancy lipid levels in the clinically normal range and preeclampsia, and a stronger association with lipid levels above the normal range.
“We found that cardiovascular risk factors that were present years before pregnancy are associated with a risk of preeclampsia,” wrote Elisabeth Balstad Magnussen, a research fellow at the Norwegian University of Science and Technology, Trondheim, and associates. “This finding suggests that unfavourable cardiovascular and metabolic profiles may represent primary causes of preeclampsia and that these factors predispose both to preeclampsia and to subsequent cardiovascular disease. This does not, however, rule out the possibility that the pre-eclamptic process in itself may also contribute to cardiovascular risk.
DNA Testing for HPV Yields Faster Results Than Cytology
DNA testing for high-risk human papillomavirus is more sensitive than cytologic testing alone and leads to earlier detection of high-grade lesions, which could mean fewer lifetime screenings for women, according to a Dutch randomized control trial.
The population-based trial comprised 45,000 women aged 2956 years taking part in the Netherlands' regular nationwide HPV-screening program. After cervical specimens were taken, the women were randomly assigned to either an intervention or a control group. Those in the intervention group were advised based on both cytologic testing and DNA results for the highest-risk varieties of HPV. For the control group, advice was based on cytologic testing with a blinded DNA test. Of those, 18,403 completed the required follow-up of 6.5 years.
Combining baseline and follow-up data, the researchers found similar detection rates for cervical intraepithelial neoplasia grade 3 or worse (CIN3+). However, significantly more CIN3+ lesions were detected in the intervention group, compared with the control group at baseline (68 of 8,575 vs. 40 of 8,580, respectively) and significantly fewer at the subsequent round of testing in the intervention and control groups (24 of 8,413 vs. 54 of 8,456), according to the study (Lancet 2007 Oct. 4 [Epub doi:10.1016/S0140-6736(07)61450-0]).
Researchers concluded that introducing HPV DNA testing could improve quality and efficiency in the health care system.
"Our results show that implementation of HPV DNA testing in cervical screening leads to earlier detection of clinically relevant cervical lesions," according to the researchers, led by Dr. Nicole W.J. Bulkmans of the pathology department at Vrije Universiteit Medisch Centrum in Amsterdam. "On the basis of these data, we suggest that the current screening interval of 5 years could be extended by at least 1 year. The extension will be advantageous to women because of a reduction in the lifetime number of screening tests and referrals."
"Long screening intervals will be an advantage not only in terms of cost but also of burden for women, and should improve participation in screening within the interval (nonparticipation is still the most important reason for later development of cervical cancer in most developed countries)," wrote Dr. Guglielmo Ronco and Dr. Nereo Segnan of the Centro Prevenzione Oncologica in Turin, Italy, in an accompanying editorial.
"Women with abnormal cytology but negative for HPV DNA had a negligible risk of CIN3+ lesions, which supports, in agreement with previous results, a screening policy based on stand-alone HPV DNA testing, with cytological tests only for triage of positive cases," they wrote (Lancet 2007 Oct. 4 [Epub doi:1016/S0140-6736(07)61480-9]).
Researchers also found a higher rate of referrals in the intervention group, compared with the control group at baseline (2.3% vs. 1.3%) and a lower rate at follow-up (1.3% vs. 1.9%). The CIN3+ rate was similar at baseline (33% vs. 32%) but was lower in the intervention group than in the control group at follow-up (25% vs. 40%), they reported.
For women with an initial negative test, those in the intervention group were at a lower risk of CIN3+ than were those in the control group with a positive test at follow-up (0.1% vs. 0.8% adjusted risk), the study found.
The adjusted risk of CIN3+ at follow-up for women with a negative HPV DNA test at baseline was 0.2%, according to the study.
Two of the researchers disclosed ties to GlaxoSmithKline, which manufactures an HPV vaccine, and one of the researchers disclosed ties to Digene Corp., which manufactures an HPV-screening test. Dr. Ronco disclosed receiving payment from Gene Probe Inc., which is developing an HPV RNA test.
DNA testing for high-risk human papillomavirus is more sensitive than cytologic testing alone and leads to earlier detection of high-grade lesions, which could mean fewer lifetime screenings for women, according to a Dutch randomized control trial.
The population-based trial comprised 45,000 women aged 2956 years taking part in the Netherlands' regular nationwide HPV-screening program. After cervical specimens were taken, the women were randomly assigned to either an intervention or a control group. Those in the intervention group were advised based on both cytologic testing and DNA results for the highest-risk varieties of HPV. For the control group, advice was based on cytologic testing with a blinded DNA test. Of those, 18,403 completed the required follow-up of 6.5 years.
Combining baseline and follow-up data, the researchers found similar detection rates for cervical intraepithelial neoplasia grade 3 or worse (CIN3+). However, significantly more CIN3+ lesions were detected in the intervention group, compared with the control group at baseline (68 of 8,575 vs. 40 of 8,580, respectively) and significantly fewer at the subsequent round of testing in the intervention and control groups (24 of 8,413 vs. 54 of 8,456), according to the study (Lancet 2007 Oct. 4 [Epub doi:10.1016/S0140-6736(07)61450-0]).
Researchers concluded that introducing HPV DNA testing could improve quality and efficiency in the health care system.
"Our results show that implementation of HPV DNA testing in cervical screening leads to earlier detection of clinically relevant cervical lesions," according to the researchers, led by Dr. Nicole W.J. Bulkmans of the pathology department at Vrije Universiteit Medisch Centrum in Amsterdam. "On the basis of these data, we suggest that the current screening interval of 5 years could be extended by at least 1 year. The extension will be advantageous to women because of a reduction in the lifetime number of screening tests and referrals."
"Long screening intervals will be an advantage not only in terms of cost but also of burden for women, and should improve participation in screening within the interval (nonparticipation is still the most important reason for later development of cervical cancer in most developed countries)," wrote Dr. Guglielmo Ronco and Dr. Nereo Segnan of the Centro Prevenzione Oncologica in Turin, Italy, in an accompanying editorial.
"Women with abnormal cytology but negative for HPV DNA had a negligible risk of CIN3+ lesions, which supports, in agreement with previous results, a screening policy based on stand-alone HPV DNA testing, with cytological tests only for triage of positive cases," they wrote (Lancet 2007 Oct. 4 [Epub doi:1016/S0140-6736(07)61480-9]).
Researchers also found a higher rate of referrals in the intervention group, compared with the control group at baseline (2.3% vs. 1.3%) and a lower rate at follow-up (1.3% vs. 1.9%). The CIN3+ rate was similar at baseline (33% vs. 32%) but was lower in the intervention group than in the control group at follow-up (25% vs. 40%), they reported.
For women with an initial negative test, those in the intervention group were at a lower risk of CIN3+ than were those in the control group with a positive test at follow-up (0.1% vs. 0.8% adjusted risk), the study found.
The adjusted risk of CIN3+ at follow-up for women with a negative HPV DNA test at baseline was 0.2%, according to the study.
Two of the researchers disclosed ties to GlaxoSmithKline, which manufactures an HPV vaccine, and one of the researchers disclosed ties to Digene Corp., which manufactures an HPV-screening test. Dr. Ronco disclosed receiving payment from Gene Probe Inc., which is developing an HPV RNA test.
DNA testing for high-risk human papillomavirus is more sensitive than cytologic testing alone and leads to earlier detection of high-grade lesions, which could mean fewer lifetime screenings for women, according to a Dutch randomized control trial.
The population-based trial comprised 45,000 women aged 2956 years taking part in the Netherlands' regular nationwide HPV-screening program. After cervical specimens were taken, the women were randomly assigned to either an intervention or a control group. Those in the intervention group were advised based on both cytologic testing and DNA results for the highest-risk varieties of HPV. For the control group, advice was based on cytologic testing with a blinded DNA test. Of those, 18,403 completed the required follow-up of 6.5 years.
Combining baseline and follow-up data, the researchers found similar detection rates for cervical intraepithelial neoplasia grade 3 or worse (CIN3+). However, significantly more CIN3+ lesions were detected in the intervention group, compared with the control group at baseline (68 of 8,575 vs. 40 of 8,580, respectively) and significantly fewer at the subsequent round of testing in the intervention and control groups (24 of 8,413 vs. 54 of 8,456), according to the study (Lancet 2007 Oct. 4 [Epub doi:10.1016/S0140-6736(07)61450-0]).
Researchers concluded that introducing HPV DNA testing could improve quality and efficiency in the health care system.
"Our results show that implementation of HPV DNA testing in cervical screening leads to earlier detection of clinically relevant cervical lesions," according to the researchers, led by Dr. Nicole W.J. Bulkmans of the pathology department at Vrije Universiteit Medisch Centrum in Amsterdam. "On the basis of these data, we suggest that the current screening interval of 5 years could be extended by at least 1 year. The extension will be advantageous to women because of a reduction in the lifetime number of screening tests and referrals."
"Long screening intervals will be an advantage not only in terms of cost but also of burden for women, and should improve participation in screening within the interval (nonparticipation is still the most important reason for later development of cervical cancer in most developed countries)," wrote Dr. Guglielmo Ronco and Dr. Nereo Segnan of the Centro Prevenzione Oncologica in Turin, Italy, in an accompanying editorial.
"Women with abnormal cytology but negative for HPV DNA had a negligible risk of CIN3+ lesions, which supports, in agreement with previous results, a screening policy based on stand-alone HPV DNA testing, with cytological tests only for triage of positive cases," they wrote (Lancet 2007 Oct. 4 [Epub doi:1016/S0140-6736(07)61480-9]).
Researchers also found a higher rate of referrals in the intervention group, compared with the control group at baseline (2.3% vs. 1.3%) and a lower rate at follow-up (1.3% vs. 1.9%). The CIN3+ rate was similar at baseline (33% vs. 32%) but was lower in the intervention group than in the control group at follow-up (25% vs. 40%), they reported.
For women with an initial negative test, those in the intervention group were at a lower risk of CIN3+ than were those in the control group with a positive test at follow-up (0.1% vs. 0.8% adjusted risk), the study found.
The adjusted risk of CIN3+ at follow-up for women with a negative HPV DNA test at baseline was 0.2%, according to the study.
Two of the researchers disclosed ties to GlaxoSmithKline, which manufactures an HPV vaccine, and one of the researchers disclosed ties to Digene Corp., which manufactures an HPV-screening test. Dr. Ronco disclosed receiving payment from Gene Probe Inc., which is developing an HPV RNA test.
H5N1 Avian Influenza Virus Can Cross Placenta
In humans, the highly pathogenic H5N1 avian influenza virus can spread beyond the lungs and also can cross the placenta to the fetus, according to research published in the Lancet.
Chinese researchers examined the postmortem tissues of two adults, a 35-year-old man from Jiangxi province and a 24-year-old woman from Anhui province who was 4 months pregnant. Both individuals were confirmed as infected with H5N1 by the Chinese Centre for Disease Control and Prevention (Lancet 2007;370:1137–45).
Examination of tissues from the respiratory, digestive, and central nervous systems, and from other organs found viral genetic material and antigens to the virus.
In the respiratory system, the researchers found signs that H5N1 had affected, among other tissues, the alveoli, in contrast to human influenza, which mainly targets the upper respiratory tract.
In the pregnant woman, the researchers found infected cells in the placenta and, in the fetus, they found viral sequences in the lungs, circulating mononuclear cells, and the liver.
The woman had been admitted after 6 days of fever, cough, and shortness of breath. She had handled ill birds 2 weeks before admission and died 2.5 days after, despite treatment with antibiotics and corticosteroids. No antivirals were given, the investigators noted. The man died 27 days after developing fever and productive cough. Admitted to hospital with a 6-day history of symptoms, he was first administered corticosteroids, followed by an antiviral, and then antifungal treatments.
The researchers said their findings help shed light on how H5N1 infections progress, which will be important for public health officials to watch because that strain of virus is feared as the most likely to result in a pandemic.
“Little is known about the specific effects in organs and cells targeted by the virus,” wrote the researchers, led by Dr. Jiang Gu of Peking University in Beijing. “The infection initially seemed to be restricted to the lungs, but later reports have suggested that influenza A H5N1 could disseminate beyond the lungs. … These newly obtained data are important in the clinical, pathological, and epidemiological investigation of human H5N1 infection and have implications for public-health and health care providers.”
In all, the researchers found viral genetic material and antigens in epithelial cells of the lungs and trachea, T cells of the lymph nodes, neurons of the brain, and Hofbauer cells and cytotrophoblasts of the placenta. They found viral genomic sequences but no antigens in the intestinal mucosa.
The route of infection for the central nervous system could be through the blood-brain barrier or through respiratory system nerves after replicating in tissues there, the researchers write. For the intestines, the virus could be bloodborne but could occur through the ingestion of respiratory secretions, they added.
How the vertical infection of the fetus would affect the fetus is unclear. Human influenza strains infecting a pregnant female have not been shown to affect the fetus, but since H5N1 also has effects on humans not seen from human strains, such as viremia, “the likelihood of virus reaching the uterus and placenta is probably higher in avian influenza than in human influenza,” they wrote.
In an accompanying commentary, Dr. Wai Fu Ng of Princess Margaret Hospital in Hong Kong and Prof. Ka Fai To of Chinese University of Hong Kong raise questions about the effects of the vertical infection route.
“The absence of pathological changes in the immunologically incompetent fetus is taken as evidence that viral replication itself is not pathogenic,” they wrote. “Speculation about the fate of the fetus if the mother survived the infection is interesting. With the development of antibodies in the mother and their transplacental crossing into the fetus, pathological lesions in the fetus may result.”
In humans, the highly pathogenic H5N1 avian influenza virus can spread beyond the lungs and also can cross the placenta to the fetus, according to research published in the Lancet.
Chinese researchers examined the postmortem tissues of two adults, a 35-year-old man from Jiangxi province and a 24-year-old woman from Anhui province who was 4 months pregnant. Both individuals were confirmed as infected with H5N1 by the Chinese Centre for Disease Control and Prevention (Lancet 2007;370:1137–45).
Examination of tissues from the respiratory, digestive, and central nervous systems, and from other organs found viral genetic material and antigens to the virus.
In the respiratory system, the researchers found signs that H5N1 had affected, among other tissues, the alveoli, in contrast to human influenza, which mainly targets the upper respiratory tract.
In the pregnant woman, the researchers found infected cells in the placenta and, in the fetus, they found viral sequences in the lungs, circulating mononuclear cells, and the liver.
The woman had been admitted after 6 days of fever, cough, and shortness of breath. She had handled ill birds 2 weeks before admission and died 2.5 days after, despite treatment with antibiotics and corticosteroids. No antivirals were given, the investigators noted. The man died 27 days after developing fever and productive cough. Admitted to hospital with a 6-day history of symptoms, he was first administered corticosteroids, followed by an antiviral, and then antifungal treatments.
The researchers said their findings help shed light on how H5N1 infections progress, which will be important for public health officials to watch because that strain of virus is feared as the most likely to result in a pandemic.
“Little is known about the specific effects in organs and cells targeted by the virus,” wrote the researchers, led by Dr. Jiang Gu of Peking University in Beijing. “The infection initially seemed to be restricted to the lungs, but later reports have suggested that influenza A H5N1 could disseminate beyond the lungs. … These newly obtained data are important in the clinical, pathological, and epidemiological investigation of human H5N1 infection and have implications for public-health and health care providers.”
In all, the researchers found viral genetic material and antigens in epithelial cells of the lungs and trachea, T cells of the lymph nodes, neurons of the brain, and Hofbauer cells and cytotrophoblasts of the placenta. They found viral genomic sequences but no antigens in the intestinal mucosa.
The route of infection for the central nervous system could be through the blood-brain barrier or through respiratory system nerves after replicating in tissues there, the researchers write. For the intestines, the virus could be bloodborne but could occur through the ingestion of respiratory secretions, they added.
How the vertical infection of the fetus would affect the fetus is unclear. Human influenza strains infecting a pregnant female have not been shown to affect the fetus, but since H5N1 also has effects on humans not seen from human strains, such as viremia, “the likelihood of virus reaching the uterus and placenta is probably higher in avian influenza than in human influenza,” they wrote.
In an accompanying commentary, Dr. Wai Fu Ng of Princess Margaret Hospital in Hong Kong and Prof. Ka Fai To of Chinese University of Hong Kong raise questions about the effects of the vertical infection route.
“The absence of pathological changes in the immunologically incompetent fetus is taken as evidence that viral replication itself is not pathogenic,” they wrote. “Speculation about the fate of the fetus if the mother survived the infection is interesting. With the development of antibodies in the mother and their transplacental crossing into the fetus, pathological lesions in the fetus may result.”
In humans, the highly pathogenic H5N1 avian influenza virus can spread beyond the lungs and also can cross the placenta to the fetus, according to research published in the Lancet.
Chinese researchers examined the postmortem tissues of two adults, a 35-year-old man from Jiangxi province and a 24-year-old woman from Anhui province who was 4 months pregnant. Both individuals were confirmed as infected with H5N1 by the Chinese Centre for Disease Control and Prevention (Lancet 2007;370:1137–45).
Examination of tissues from the respiratory, digestive, and central nervous systems, and from other organs found viral genetic material and antigens to the virus.
In the respiratory system, the researchers found signs that H5N1 had affected, among other tissues, the alveoli, in contrast to human influenza, which mainly targets the upper respiratory tract.
In the pregnant woman, the researchers found infected cells in the placenta and, in the fetus, they found viral sequences in the lungs, circulating mononuclear cells, and the liver.
The woman had been admitted after 6 days of fever, cough, and shortness of breath. She had handled ill birds 2 weeks before admission and died 2.5 days after, despite treatment with antibiotics and corticosteroids. No antivirals were given, the investigators noted. The man died 27 days after developing fever and productive cough. Admitted to hospital with a 6-day history of symptoms, he was first administered corticosteroids, followed by an antiviral, and then antifungal treatments.
The researchers said their findings help shed light on how H5N1 infections progress, which will be important for public health officials to watch because that strain of virus is feared as the most likely to result in a pandemic.
“Little is known about the specific effects in organs and cells targeted by the virus,” wrote the researchers, led by Dr. Jiang Gu of Peking University in Beijing. “The infection initially seemed to be restricted to the lungs, but later reports have suggested that influenza A H5N1 could disseminate beyond the lungs. … These newly obtained data are important in the clinical, pathological, and epidemiological investigation of human H5N1 infection and have implications for public-health and health care providers.”
In all, the researchers found viral genetic material and antigens in epithelial cells of the lungs and trachea, T cells of the lymph nodes, neurons of the brain, and Hofbauer cells and cytotrophoblasts of the placenta. They found viral genomic sequences but no antigens in the intestinal mucosa.
The route of infection for the central nervous system could be through the blood-brain barrier or through respiratory system nerves after replicating in tissues there, the researchers write. For the intestines, the virus could be bloodborne but could occur through the ingestion of respiratory secretions, they added.
How the vertical infection of the fetus would affect the fetus is unclear. Human influenza strains infecting a pregnant female have not been shown to affect the fetus, but since H5N1 also has effects on humans not seen from human strains, such as viremia, “the likelihood of virus reaching the uterus and placenta is probably higher in avian influenza than in human influenza,” they wrote.
In an accompanying commentary, Dr. Wai Fu Ng of Princess Margaret Hospital in Hong Kong and Prof. Ka Fai To of Chinese University of Hong Kong raise questions about the effects of the vertical infection route.
“The absence of pathological changes in the immunologically incompetent fetus is taken as evidence that viral replication itself is not pathogenic,” they wrote. “Speculation about the fate of the fetus if the mother survived the infection is interesting. With the development of antibodies in the mother and their transplacental crossing into the fetus, pathological lesions in the fetus may result.”