Obesity Carries Pregnancy Risks
Obese Women More Likely to Have Babies With Birth Defects, Study Shows
WebMD News Archive
Obesity & Birth Defects: Results continued...
The definitions of overweight and obese differed somewhat from study to
study, but many studies used those set by the World Health Organization -- a
body mass index or BMI of 25 and above for overweight and 30 and above for
More research is needed to determine if the link between excess weight and
birth defects holds for overweight women. "There isn't the same amount of
research evidence for overweight as there is for obesity,'' Rankin says.
Obesity & Birth Defects: Explaining the Link
Exactly how obesity increases birth defect risk isn't known, but the
researchers offer possible explanations.
- Because maternal diabetes is known to increase the risk of birth defects,
and obese women are at higher risk for type 2 diabetes, the mother-to-be may
have undiagnosed diabetes.
- Obese women have been shown to have nutritional deficiencies, especially
reduced levels of folate, which is important to prevent neural tube defects.
Obese women may need more than the amount routinely recommended to prevent
Obesity & Birth Defects: Other Opinions
The new review further confirms what physicians have known for a long time,
says Sina Haeri, MD, a clinical instructor of maternal-fetal medicine and a
fellow at the University of North Carolina at Chapel Hill School of
The problem with some of the previous studies, he tells WebMD, is that they
had some methodological weaknesses. "So we took it all with a grain of
salt," says Haeri, who recently reported that teen moms who are obese are
more likely to be diagnosed with diabetes during the pregnancy (gestational
diabetes) and to have cesarean deliveries.
In the new analysis, he says, the U.K. researchers took all the smaller
studies and looked at them together and still found the obesity and birth
The new analysis confirms in a convincing way what physicians have been
observing and studies have been suggesting for a few years, says Peter
Bernstein, MD, a maternal-fetal medicine specialist at Montefiore Medical
Center and Albert Einstein College of Medicine, New York.
Obesity & Birth Defects: Preconception Counseling
Women who are obese should have preconception counseling to minimize the
risks of their excess weight to the newborns, Rankin says.