Obesity Carries Pregnancy Risks
Obese Women More Likely to Have Babies With Birth Defects, Study Shows
Feb. 10, 2009 -- Women who are obese during pregnancy have a higher risk than normal-weight women of having babies with certain birth defects, including neural tube defects such as spina bifida, heart problems, and cleft palate and lip, according to a new review.
"It is important to note that birth defects are a rare event and occur in 2%-4% of pregnancies, so the risk remains very low," says Judith Rankin, PhD, a study co-author and a reader in material and perinatal epidemiology at the University of Newcastle in England. "The last thing we want to do is scare women.”
Rather, the goal is to inform them, she says, and to encourage women who are obese to get preconception counseling about weight loss.
The new report, published in this week's Journal of the American Medical Association, is a review of previously published work. Rankin and her colleagues culled the medical literature, pooled the results of 18 studies, and reviewed the findings of 39 other studies to determine if the association between obesity and birth defects still held up. It did.
Obesity & Birth Defects: The Study
Rankin's team undertook the study because of the growing problem of obesity in women of childbearing age. In the U.S., one-third of women 15 and older are obese, the authors note, and those numbers are expected to rise.
"This is a very important public health issue given the growing numbers of women who are obese at the start of pregnancy," says Rankin, who notes that obesity is also increasing in the U.K.
Obesity & Birth Defects: Results
In the new analysis, women who were obese before pregnancy or in early pregnancy had a significantly increased risk of having a baby with birth defects. The risks differed for specific problems.
- The risk of spina bifida was more than two times as high for obese pregnant women, and the overall risk of neural tube defects was nearly twice as high.
- The risk of cardiovascular defects was 30% higher.
- The risk of cleft lip and cleft palate, either singly or together, was about 20% higher.
- The risk of hydrocephaly (an abnormal buildup of fluid in the brain) was 60% higher.
- Limb reduction abnormalities were 30% higher.