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WASHINGTON – Cardiovascular risk factors may be elevated “as soon as the first postpartum year” in women who have gestational diabetes or hypertensive disorders of pregnancy, recent findings have affirmed, Deborah B. Ehrenthal, MD, MPH, said at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
Dr. Ehrenthal was one of several researchers who urged innovative strategies and improved care coordination to boost women’s follow-up after gestational diabetes mellitus (GDM) and other adverse pregnancy outcomes and complications. “The metabolic stress of pregnancy can uncover underlying susceptibilities,” she said. “And ”
Evidence that adverse pregnancy outcomes – including GDM and hypertensive disorders of pregnancy (HDP) – can elevate cardiovascular risk comes most recently from the Nulliparous Pregnancy Outcomes Study – Monitoring Mothers to be Heart Health Study (nuMoM2b–HHS study), a prospective observational cohort that followed 4,484 women 2-7 years after their first pregnancy. Women had a follow-up exam, with blood pressure and anthropometric measurements and clinical/biological testing, an average of 3 years post partum.
An analysis published in October 2019 in the Journal of the American Heart Association shows that women with HDP (including preeclampsia and gestational hypertension) had a relative risk of hypertension of 2.5 at follow-up, compared with women without HDP. Women who had preeclampsia specifically were 2.3 times as likely as were women who did not have preeclampsia to have incident hypertension at follow-up, said Dr. Ehrenthal, a coinvestigator of the study.
The analysis focused on incident hypertension as the primary outcome, and adjusted for age, body mass index, and other important cardiovascular disease risk factors, she noted. Researchers utilized the diagnostic threshold for hypertension extant at the time of study design: A systolic blood pressure of 140 mm Hg or greater, or a diastolic BP of 90 mm Hg or greater (J Am Heart Assoc. 2019;8:e013092).
HDP was the most common adverse pregnancy outcome in the nuMoM2b–HHS study (14%). Among all participants, 4% had GDM. Approximately 82% had neither HDP nor GDM. Other adverse pregnancy outcomes included in the analysis were preterm birth, small-for-gestational-age birth, and stillbirth.
Additional preliminary estimates presented by Dr. Ehrenthal show that, based on the new (2017) lower threshold for hypertension – 130 mg Hg systolic or 80 mm Hg diastolic – the disorder afflicted 37% of women who had experienced HDP (relative risk 2.1), and 32% of women who had GDM (RR 1.8). Prediabetes/diabetes (using a fasting blood glucose threshold of 100 mg/dL) at follow-up affected an estimated 21% of women who had HDP (RR 1.4) and 38% of women who had GDM (RR 2.5).
Notably, across the entire study cohort, 20% had hypertension at follow-up, “which is extraordinary” considering the short time frame from pregnancy and the young age of the study population – a mean maternal age of 27 years, said Dr. Ehrenthal, associate professor of population health sciences and obstetrics & gynecology at the University of Wisconsin, Madison.
Also across the cohort, 15% had prediabetes/diabetes at follow-up. “We need to think about women more generally,” she cautioned. “While we recognize the significant elevated risk of HDP and GDM [for the development of subsequent hypertension and cardiovascular risk], we will miss a lot of women [if we focus only on the history of HDP and GDM.]”
The majority of women found to have hypertension or prediabetes/diabetes at follow-up had experienced neither HDP nor GDM, but a good many of them (47% of those who had hypertension and 47% of those found to have prediabetes/diabetes) had a BMI of 30 or above, Dr. Ehrenthal said at the DPSG-NA meeting.
Nurses Health Study, hyperglycemia and adverse pregnancy outcome follow-up data
The new findings from the nuMoM2b–HHS study add to a robust and growing body of evidence that pregnancy is an important window to future health, and that follow up and screening after GDM and HDP are crucial.
Regarding GDM specifically, “there’s quite a bit of literature by now demonstrating that GDM history is a risk factor for hypertension, even 1-2 years post partum, and that the risk is elevated as well for dyslipidemia and vascular dysfunction,” Deirdre K. Tobias, D.Sc., an epidemiologist at Brigham and Women’s Hospital and assistant professor of nutrition at Harvard TH Chan School of Public Health, Boston, said at the DPSG meeting.
An analysis of the Nurses Health Study II (NHS II) cohort published in 2017 found a 40% higher relative risk of cardiovascular disease events (largely myocardial infarction) in women who had GDM, compared with women who did not have GDM over a median follow-up of 26 years. This was after adjustments were made for age, time since pregnancy, menopausal status, family history of MI or stroke, hypertension in pregnancy, white race/ethnicity, prepregnancy BMI, and other factors (JAMA Intern Med. 2017;177[12]:1735-42).
The NHS data also have shown, however, that the elevated risk for cardiovascular disease after a GDM pregnancy “can be mitigated by adopting a healthy lifestyle,” said Dr. Tobias, lead author of the 2017 NHS II analysis. Adjustments for postpregnancy weight gain and lifestyle factors attenuated the relative risk of cardiovascular disease events after a GDM pregnancy to a 30% increased risk.
Dr. Tobias and colleagues currently are looking within the NHS cohort for “metabolomic signatures” or signals – various amino acid and lipid metabolites – to identify the progression of GDM to type 2 diabetes. Metabolomics “may help further refine our understanding of the long-term links between GDM and prevention of type 2 diabetes and of cardiovascular disease in mothers,” she said.
The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Follow-Up Study, in the meantime, is documenting associations of maternal glucose levels during pregnancy not only with prediabetes or type 2 diabetes 10-14 years later, but also with measures of cardiovascular risk in mothers 10-14 years later.
Just as perinatal outcomes were strongly associated with glucose as a continuous variable in the original HAPO study, “it’s clear there’s a progressive increase in the risk of [later] disorders of glucose metabolism as [fasting blood glucose levels and 1- and-2-hour glucose values] in pregnancy are higher,” said Boyd E. Metzger, MD, the Tom D. Spies emeritus professor of metabolism and nutrition at Northwestern University, Chicago, and principal investigator of the original HAPO study and its follow up.
“Another message is that the more normal you are in pregnancy, the more normal you will be many years later. Good values [during pregnancy] produce good outcomes.”
Currently unpublished data from the HAPO Follow-Up Study are being analyzed, but it appears thus far that GDM is not associated with hypertension (per the old diagnostic threshold) in this cohort after adjustment for maternal age, BMI, smoking, and family history of hypertension. GDM appears to be a significant risk factor for dyslipidemia, however. HDL cholesterol at follow-up was significantly lower for mothers who had GDM compared with those without, whereas LDL cholesterol and triglycerides at follow-up were significantly higher for mothers with GDM, Dr. Metzger said.
Racial/ethnic disparities, postpartum care
Neither long-term study – the NHS II or the HAPO Follow-Up Study – has looked at racial and ethnic differences. The HAPO cohort is racially-ethnically diverse but the NHS II cohort is predominantly white women.
Research suggests that GDM is a heterogeneous condition with some unique phenotypes in subgroups that vary by race and ethnicity. And just as there appear to be racial-ethnic differences in the pathophysiology of GDM, there appear to be racial-ethnic differences in the progression to type 2 diabetes – a known risk factor for cardiovascular disease, said Monique Henderson, PhD, a research scientist at Kaiser Permanente Northern California (KPNC).
On the broadest level, while Asian Americans have the highest prevalence of GDM, African Americans have the highest rates of progressing to type 2 diabetes, Dr. Henderson said. Disparities “may [stem from] metabolic differences in terms of insulin resistance and secretion that are different between pregnancy and the postpartum period, and that might vary [across racial-ethnic subgroups],” she said. Lifestyle differences and variation in postpartum screening rates also may play a role.
At KPNC, where women with GDM receive calls and letters reminding them of the need for postpartum screening, only 48% overall completed an oral glucose tolerance test at 4-12 weeks post partum, as recommended by both the American Diabetes Association and the American College of Obstetricians and Gynecologists. Both before and after adjustment for education, attendance at a postpartum visit, and other variables, Chinese women were most likely to have screening, and black women were least likely, said Dr. Henderson, referring to ongoing research.
A study Dr. Ehrenthal led of women with GDM or HDP recruited from the postpartum service of a large community-based, academic obstetrical hospital in Delaware showed that while nearly all women attended a 6-week postpartum visit with their ob.gyns., 59% of women with GDM had not yet completed diabetes screening when they were interviewed 3 months post partum. Most women with HDP indicated they had follow-up blood pressure testing, and just over half of women with either diagnosis recalled having ever had lipid testing (J Women’s Health 2014;23[9]:760-4).
Women least likely to complete screening tests were those who had no college education, those who had less than a high school level of health literacy, and those who were not privately insured, Dr. Ehrenthal said.
A large national study of privately insured women also found low rates of follow-up testing, however. While the majority of women with GDM had a postpartum visit with an obstetrician or primary care physician within a year after delivery, only a minority of women had a glycemic screening test completed (Obstet Gynecol. 2016;128[1]:159-67).
“We can’t place the blame on women,” Dr. Ehrenthal said. “We need increased attention to screening,” including screening for cardiovascular disease risk factors, and a “deliberate hand-off to primary care.”
For follow-up cardiovascular disease risk factor assessment after HDP, ACOG recommends periodic (perhaps annually) assessment and referral for treatment as needed, and the cardiology professional organizations recommend that pregnancy history be considered when assessing risk in order to decide on lipid treatment, she noted.
Each of the speakers reported that they have no financial or other interests that pose a conflict of interest. The HAPO Follow-Up Study is funded by the National Institute of Diabetes and Digestive and Kidney Diseases, and the nuMoM2b–HHS study has been funded by several National Institutes of Health institutes and other programs and initiatives.
WASHINGTON – Cardiovascular risk factors may be elevated “as soon as the first postpartum year” in women who have gestational diabetes or hypertensive disorders of pregnancy, recent findings have affirmed, Deborah B. Ehrenthal, MD, MPH, said at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
Dr. Ehrenthal was one of several researchers who urged innovative strategies and improved care coordination to boost women’s follow-up after gestational diabetes mellitus (GDM) and other adverse pregnancy outcomes and complications. “The metabolic stress of pregnancy can uncover underlying susceptibilities,” she said. “And ”
Evidence that adverse pregnancy outcomes – including GDM and hypertensive disorders of pregnancy (HDP) – can elevate cardiovascular risk comes most recently from the Nulliparous Pregnancy Outcomes Study – Monitoring Mothers to be Heart Health Study (nuMoM2b–HHS study), a prospective observational cohort that followed 4,484 women 2-7 years after their first pregnancy. Women had a follow-up exam, with blood pressure and anthropometric measurements and clinical/biological testing, an average of 3 years post partum.
An analysis published in October 2019 in the Journal of the American Heart Association shows that women with HDP (including preeclampsia and gestational hypertension) had a relative risk of hypertension of 2.5 at follow-up, compared with women without HDP. Women who had preeclampsia specifically were 2.3 times as likely as were women who did not have preeclampsia to have incident hypertension at follow-up, said Dr. Ehrenthal, a coinvestigator of the study.
The analysis focused on incident hypertension as the primary outcome, and adjusted for age, body mass index, and other important cardiovascular disease risk factors, she noted. Researchers utilized the diagnostic threshold for hypertension extant at the time of study design: A systolic blood pressure of 140 mm Hg or greater, or a diastolic BP of 90 mm Hg or greater (J Am Heart Assoc. 2019;8:e013092).
HDP was the most common adverse pregnancy outcome in the nuMoM2b–HHS study (14%). Among all participants, 4% had GDM. Approximately 82% had neither HDP nor GDM. Other adverse pregnancy outcomes included in the analysis were preterm birth, small-for-gestational-age birth, and stillbirth.
Additional preliminary estimates presented by Dr. Ehrenthal show that, based on the new (2017) lower threshold for hypertension – 130 mg Hg systolic or 80 mm Hg diastolic – the disorder afflicted 37% of women who had experienced HDP (relative risk 2.1), and 32% of women who had GDM (RR 1.8). Prediabetes/diabetes (using a fasting blood glucose threshold of 100 mg/dL) at follow-up affected an estimated 21% of women who had HDP (RR 1.4) and 38% of women who had GDM (RR 2.5).
Notably, across the entire study cohort, 20% had hypertension at follow-up, “which is extraordinary” considering the short time frame from pregnancy and the young age of the study population – a mean maternal age of 27 years, said Dr. Ehrenthal, associate professor of population health sciences and obstetrics & gynecology at the University of Wisconsin, Madison.
Also across the cohort, 15% had prediabetes/diabetes at follow-up. “We need to think about women more generally,” she cautioned. “While we recognize the significant elevated risk of HDP and GDM [for the development of subsequent hypertension and cardiovascular risk], we will miss a lot of women [if we focus only on the history of HDP and GDM.]”
The majority of women found to have hypertension or prediabetes/diabetes at follow-up had experienced neither HDP nor GDM, but a good many of them (47% of those who had hypertension and 47% of those found to have prediabetes/diabetes) had a BMI of 30 or above, Dr. Ehrenthal said at the DPSG-NA meeting.
Nurses Health Study, hyperglycemia and adverse pregnancy outcome follow-up data
The new findings from the nuMoM2b–HHS study add to a robust and growing body of evidence that pregnancy is an important window to future health, and that follow up and screening after GDM and HDP are crucial.
Regarding GDM specifically, “there’s quite a bit of literature by now demonstrating that GDM history is a risk factor for hypertension, even 1-2 years post partum, and that the risk is elevated as well for dyslipidemia and vascular dysfunction,” Deirdre K. Tobias, D.Sc., an epidemiologist at Brigham and Women’s Hospital and assistant professor of nutrition at Harvard TH Chan School of Public Health, Boston, said at the DPSG meeting.
An analysis of the Nurses Health Study II (NHS II) cohort published in 2017 found a 40% higher relative risk of cardiovascular disease events (largely myocardial infarction) in women who had GDM, compared with women who did not have GDM over a median follow-up of 26 years. This was after adjustments were made for age, time since pregnancy, menopausal status, family history of MI or stroke, hypertension in pregnancy, white race/ethnicity, prepregnancy BMI, and other factors (JAMA Intern Med. 2017;177[12]:1735-42).
The NHS data also have shown, however, that the elevated risk for cardiovascular disease after a GDM pregnancy “can be mitigated by adopting a healthy lifestyle,” said Dr. Tobias, lead author of the 2017 NHS II analysis. Adjustments for postpregnancy weight gain and lifestyle factors attenuated the relative risk of cardiovascular disease events after a GDM pregnancy to a 30% increased risk.
Dr. Tobias and colleagues currently are looking within the NHS cohort for “metabolomic signatures” or signals – various amino acid and lipid metabolites – to identify the progression of GDM to type 2 diabetes. Metabolomics “may help further refine our understanding of the long-term links between GDM and prevention of type 2 diabetes and of cardiovascular disease in mothers,” she said.
The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Follow-Up Study, in the meantime, is documenting associations of maternal glucose levels during pregnancy not only with prediabetes or type 2 diabetes 10-14 years later, but also with measures of cardiovascular risk in mothers 10-14 years later.
Just as perinatal outcomes were strongly associated with glucose as a continuous variable in the original HAPO study, “it’s clear there’s a progressive increase in the risk of [later] disorders of glucose metabolism as [fasting blood glucose levels and 1- and-2-hour glucose values] in pregnancy are higher,” said Boyd E. Metzger, MD, the Tom D. Spies emeritus professor of metabolism and nutrition at Northwestern University, Chicago, and principal investigator of the original HAPO study and its follow up.
“Another message is that the more normal you are in pregnancy, the more normal you will be many years later. Good values [during pregnancy] produce good outcomes.”
Currently unpublished data from the HAPO Follow-Up Study are being analyzed, but it appears thus far that GDM is not associated with hypertension (per the old diagnostic threshold) in this cohort after adjustment for maternal age, BMI, smoking, and family history of hypertension. GDM appears to be a significant risk factor for dyslipidemia, however. HDL cholesterol at follow-up was significantly lower for mothers who had GDM compared with those without, whereas LDL cholesterol and triglycerides at follow-up were significantly higher for mothers with GDM, Dr. Metzger said.
Racial/ethnic disparities, postpartum care
Neither long-term study – the NHS II or the HAPO Follow-Up Study – has looked at racial and ethnic differences. The HAPO cohort is racially-ethnically diverse but the NHS II cohort is predominantly white women.
Research suggests that GDM is a heterogeneous condition with some unique phenotypes in subgroups that vary by race and ethnicity. And just as there appear to be racial-ethnic differences in the pathophysiology of GDM, there appear to be racial-ethnic differences in the progression to type 2 diabetes – a known risk factor for cardiovascular disease, said Monique Henderson, PhD, a research scientist at Kaiser Permanente Northern California (KPNC).
On the broadest level, while Asian Americans have the highest prevalence of GDM, African Americans have the highest rates of progressing to type 2 diabetes, Dr. Henderson said. Disparities “may [stem from] metabolic differences in terms of insulin resistance and secretion that are different between pregnancy and the postpartum period, and that might vary [across racial-ethnic subgroups],” she said. Lifestyle differences and variation in postpartum screening rates also may play a role.
At KPNC, where women with GDM receive calls and letters reminding them of the need for postpartum screening, only 48% overall completed an oral glucose tolerance test at 4-12 weeks post partum, as recommended by both the American Diabetes Association and the American College of Obstetricians and Gynecologists. Both before and after adjustment for education, attendance at a postpartum visit, and other variables, Chinese women were most likely to have screening, and black women were least likely, said Dr. Henderson, referring to ongoing research.
A study Dr. Ehrenthal led of women with GDM or HDP recruited from the postpartum service of a large community-based, academic obstetrical hospital in Delaware showed that while nearly all women attended a 6-week postpartum visit with their ob.gyns., 59% of women with GDM had not yet completed diabetes screening when they were interviewed 3 months post partum. Most women with HDP indicated they had follow-up blood pressure testing, and just over half of women with either diagnosis recalled having ever had lipid testing (J Women’s Health 2014;23[9]:760-4).
Women least likely to complete screening tests were those who had no college education, those who had less than a high school level of health literacy, and those who were not privately insured, Dr. Ehrenthal said.
A large national study of privately insured women also found low rates of follow-up testing, however. While the majority of women with GDM had a postpartum visit with an obstetrician or primary care physician within a year after delivery, only a minority of women had a glycemic screening test completed (Obstet Gynecol. 2016;128[1]:159-67).
“We can’t place the blame on women,” Dr. Ehrenthal said. “We need increased attention to screening,” including screening for cardiovascular disease risk factors, and a “deliberate hand-off to primary care.”
For follow-up cardiovascular disease risk factor assessment after HDP, ACOG recommends periodic (perhaps annually) assessment and referral for treatment as needed, and the cardiology professional organizations recommend that pregnancy history be considered when assessing risk in order to decide on lipid treatment, she noted.
Each of the speakers reported that they have no financial or other interests that pose a conflict of interest. The HAPO Follow-Up Study is funded by the National Institute of Diabetes and Digestive and Kidney Diseases, and the nuMoM2b–HHS study has been funded by several National Institutes of Health institutes and other programs and initiatives.
WASHINGTON – Cardiovascular risk factors may be elevated “as soon as the first postpartum year” in women who have gestational diabetes or hypertensive disorders of pregnancy, recent findings have affirmed, Deborah B. Ehrenthal, MD, MPH, said at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
Dr. Ehrenthal was one of several researchers who urged innovative strategies and improved care coordination to boost women’s follow-up after gestational diabetes mellitus (GDM) and other adverse pregnancy outcomes and complications. “The metabolic stress of pregnancy can uncover underlying susceptibilities,” she said. “And ”
Evidence that adverse pregnancy outcomes – including GDM and hypertensive disorders of pregnancy (HDP) – can elevate cardiovascular risk comes most recently from the Nulliparous Pregnancy Outcomes Study – Monitoring Mothers to be Heart Health Study (nuMoM2b–HHS study), a prospective observational cohort that followed 4,484 women 2-7 years after their first pregnancy. Women had a follow-up exam, with blood pressure and anthropometric measurements and clinical/biological testing, an average of 3 years post partum.
An analysis published in October 2019 in the Journal of the American Heart Association shows that women with HDP (including preeclampsia and gestational hypertension) had a relative risk of hypertension of 2.5 at follow-up, compared with women without HDP. Women who had preeclampsia specifically were 2.3 times as likely as were women who did not have preeclampsia to have incident hypertension at follow-up, said Dr. Ehrenthal, a coinvestigator of the study.
The analysis focused on incident hypertension as the primary outcome, and adjusted for age, body mass index, and other important cardiovascular disease risk factors, she noted. Researchers utilized the diagnostic threshold for hypertension extant at the time of study design: A systolic blood pressure of 140 mm Hg or greater, or a diastolic BP of 90 mm Hg or greater (J Am Heart Assoc. 2019;8:e013092).
HDP was the most common adverse pregnancy outcome in the nuMoM2b–HHS study (14%). Among all participants, 4% had GDM. Approximately 82% had neither HDP nor GDM. Other adverse pregnancy outcomes included in the analysis were preterm birth, small-for-gestational-age birth, and stillbirth.
Additional preliminary estimates presented by Dr. Ehrenthal show that, based on the new (2017) lower threshold for hypertension – 130 mg Hg systolic or 80 mm Hg diastolic – the disorder afflicted 37% of women who had experienced HDP (relative risk 2.1), and 32% of women who had GDM (RR 1.8). Prediabetes/diabetes (using a fasting blood glucose threshold of 100 mg/dL) at follow-up affected an estimated 21% of women who had HDP (RR 1.4) and 38% of women who had GDM (RR 2.5).
Notably, across the entire study cohort, 20% had hypertension at follow-up, “which is extraordinary” considering the short time frame from pregnancy and the young age of the study population – a mean maternal age of 27 years, said Dr. Ehrenthal, associate professor of population health sciences and obstetrics & gynecology at the University of Wisconsin, Madison.
Also across the cohort, 15% had prediabetes/diabetes at follow-up. “We need to think about women more generally,” she cautioned. “While we recognize the significant elevated risk of HDP and GDM [for the development of subsequent hypertension and cardiovascular risk], we will miss a lot of women [if we focus only on the history of HDP and GDM.]”
The majority of women found to have hypertension or prediabetes/diabetes at follow-up had experienced neither HDP nor GDM, but a good many of them (47% of those who had hypertension and 47% of those found to have prediabetes/diabetes) had a BMI of 30 or above, Dr. Ehrenthal said at the DPSG-NA meeting.
Nurses Health Study, hyperglycemia and adverse pregnancy outcome follow-up data
The new findings from the nuMoM2b–HHS study add to a robust and growing body of evidence that pregnancy is an important window to future health, and that follow up and screening after GDM and HDP are crucial.
Regarding GDM specifically, “there’s quite a bit of literature by now demonstrating that GDM history is a risk factor for hypertension, even 1-2 years post partum, and that the risk is elevated as well for dyslipidemia and vascular dysfunction,” Deirdre K. Tobias, D.Sc., an epidemiologist at Brigham and Women’s Hospital and assistant professor of nutrition at Harvard TH Chan School of Public Health, Boston, said at the DPSG meeting.
An analysis of the Nurses Health Study II (NHS II) cohort published in 2017 found a 40% higher relative risk of cardiovascular disease events (largely myocardial infarction) in women who had GDM, compared with women who did not have GDM over a median follow-up of 26 years. This was after adjustments were made for age, time since pregnancy, menopausal status, family history of MI or stroke, hypertension in pregnancy, white race/ethnicity, prepregnancy BMI, and other factors (JAMA Intern Med. 2017;177[12]:1735-42).
The NHS data also have shown, however, that the elevated risk for cardiovascular disease after a GDM pregnancy “can be mitigated by adopting a healthy lifestyle,” said Dr. Tobias, lead author of the 2017 NHS II analysis. Adjustments for postpregnancy weight gain and lifestyle factors attenuated the relative risk of cardiovascular disease events after a GDM pregnancy to a 30% increased risk.
Dr. Tobias and colleagues currently are looking within the NHS cohort for “metabolomic signatures” or signals – various amino acid and lipid metabolites – to identify the progression of GDM to type 2 diabetes. Metabolomics “may help further refine our understanding of the long-term links between GDM and prevention of type 2 diabetes and of cardiovascular disease in mothers,” she said.
The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Follow-Up Study, in the meantime, is documenting associations of maternal glucose levels during pregnancy not only with prediabetes or type 2 diabetes 10-14 years later, but also with measures of cardiovascular risk in mothers 10-14 years later.
Just as perinatal outcomes were strongly associated with glucose as a continuous variable in the original HAPO study, “it’s clear there’s a progressive increase in the risk of [later] disorders of glucose metabolism as [fasting blood glucose levels and 1- and-2-hour glucose values] in pregnancy are higher,” said Boyd E. Metzger, MD, the Tom D. Spies emeritus professor of metabolism and nutrition at Northwestern University, Chicago, and principal investigator of the original HAPO study and its follow up.
“Another message is that the more normal you are in pregnancy, the more normal you will be many years later. Good values [during pregnancy] produce good outcomes.”
Currently unpublished data from the HAPO Follow-Up Study are being analyzed, but it appears thus far that GDM is not associated with hypertension (per the old diagnostic threshold) in this cohort after adjustment for maternal age, BMI, smoking, and family history of hypertension. GDM appears to be a significant risk factor for dyslipidemia, however. HDL cholesterol at follow-up was significantly lower for mothers who had GDM compared with those without, whereas LDL cholesterol and triglycerides at follow-up were significantly higher for mothers with GDM, Dr. Metzger said.
Racial/ethnic disparities, postpartum care
Neither long-term study – the NHS II or the HAPO Follow-Up Study – has looked at racial and ethnic differences. The HAPO cohort is racially-ethnically diverse but the NHS II cohort is predominantly white women.
Research suggests that GDM is a heterogeneous condition with some unique phenotypes in subgroups that vary by race and ethnicity. And just as there appear to be racial-ethnic differences in the pathophysiology of GDM, there appear to be racial-ethnic differences in the progression to type 2 diabetes – a known risk factor for cardiovascular disease, said Monique Henderson, PhD, a research scientist at Kaiser Permanente Northern California (KPNC).
On the broadest level, while Asian Americans have the highest prevalence of GDM, African Americans have the highest rates of progressing to type 2 diabetes, Dr. Henderson said. Disparities “may [stem from] metabolic differences in terms of insulin resistance and secretion that are different between pregnancy and the postpartum period, and that might vary [across racial-ethnic subgroups],” she said. Lifestyle differences and variation in postpartum screening rates also may play a role.
At KPNC, where women with GDM receive calls and letters reminding them of the need for postpartum screening, only 48% overall completed an oral glucose tolerance test at 4-12 weeks post partum, as recommended by both the American Diabetes Association and the American College of Obstetricians and Gynecologists. Both before and after adjustment for education, attendance at a postpartum visit, and other variables, Chinese women were most likely to have screening, and black women were least likely, said Dr. Henderson, referring to ongoing research.
A study Dr. Ehrenthal led of women with GDM or HDP recruited from the postpartum service of a large community-based, academic obstetrical hospital in Delaware showed that while nearly all women attended a 6-week postpartum visit with their ob.gyns., 59% of women with GDM had not yet completed diabetes screening when they were interviewed 3 months post partum. Most women with HDP indicated they had follow-up blood pressure testing, and just over half of women with either diagnosis recalled having ever had lipid testing (J Women’s Health 2014;23[9]:760-4).
Women least likely to complete screening tests were those who had no college education, those who had less than a high school level of health literacy, and those who were not privately insured, Dr. Ehrenthal said.
A large national study of privately insured women also found low rates of follow-up testing, however. While the majority of women with GDM had a postpartum visit with an obstetrician or primary care physician within a year after delivery, only a minority of women had a glycemic screening test completed (Obstet Gynecol. 2016;128[1]:159-67).
“We can’t place the blame on women,” Dr. Ehrenthal said. “We need increased attention to screening,” including screening for cardiovascular disease risk factors, and a “deliberate hand-off to primary care.”
For follow-up cardiovascular disease risk factor assessment after HDP, ACOG recommends periodic (perhaps annually) assessment and referral for treatment as needed, and the cardiology professional organizations recommend that pregnancy history be considered when assessing risk in order to decide on lipid treatment, she noted.
Each of the speakers reported that they have no financial or other interests that pose a conflict of interest. The HAPO Follow-Up Study is funded by the National Institute of Diabetes and Digestive and Kidney Diseases, and the nuMoM2b–HHS study has been funded by several National Institutes of Health institutes and other programs and initiatives.
REPORTING FROM THE DPSG-NA 2019