Even a Little Overweight is Bad for Baby

Overweight pregnant moms with high blood sugar have higher risk of pregnancy problems

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) If you think being just a little overweight won't present problems for your pregnancy, think again. Addressing your weight could mean a safer delivery for you and your baby.

Although doctors have typically been more concerned about the risks for pregnancies of obese women or women with gestational diabetes, a new study reveals that even being just above average in terms of weight and blood sugar can be just as risky - if not more.

"Get to a healthy weight before getting pregnant."

Boyd Metzger, MD, a professor of medicine-endocrinology at Northwestern University Feinberg School of Medicine and a doctor at Northwestern Memorial Hospital, led the study investigating those women who typically fall through the cracks in terms of caregivers' assessments of their pregnancy risks.

Metzger and colleagues investigated 23,316 women from nine countries who were enrolled in the Hyperglycemia and Adverse Pregnancy Outcome Study.

About 16 percent of the women were obese, and nearly 14 percent had gestational diabetes. Another 6 percent were neither but were overweight and did have higher than normal blood sugar levels.

Each woman took an oral glucose tolerance test between 24 and 32 weeks of pregnancy and had her body mass index - a measure of healthy weight - calculated.

The problems included in the list of adverse pregnancy outcomes were high birth weight of a baby, babies with a high percentage of body fat, C-section, pre-eclampsia (pregnancy-induced high blood pressure) and any birth injuries, such as a newborn's shoulder dislocation.

As with past research, obese women who also had gestational diabetes continued to show the greatest risk of something going wrong during a pregnancy compared to women who are one or the other. These women were more than three and a half times as likely to have babies above the 90th percentile for weight.

Women with gestational diabetes were a little more than twice as likely to have babies that were overweight, and obese women were 1.7 times as likely to have heavier babies.

These three groups of women were also at higher risk for having a C-section, pre-eclampsia or a baby with a high percentage of body fat.

But Metzger's team found that those women cruising just barely under the danger zone typically watched by doctors - overweight with high blood sugar, but neither obese nor gestational diabetic - actually had a higher risk of pregnancy problems than women who were only obese or only had gestational diabetes but not both.

"These are women who have not been on our radar because they don't have gestational diabetes and aren't obese, but our study shows if you are one step away from each of those, you carry some significant risks," Metzger said. "We need to address the combination of overweight and blood sugar of these women as urgently as we do for women who are obese or have gestational diabetes."

Babies with weights in the top 10 percent were classified as an adverse outcome because a larger baby means a larger risk of injury during a vaginal delivery as well as a greater risk of the mother needing a C-section.

Past studies had already shown that obese mothers were more likely to have larger babies, and this study's findings confirmed those of past research.

Obese mothers with gestational diabetes tend to have babies weighing about 0.75 pounds heavier than mothers with normal weight and normal blood sugar levels.

Overweight mothers who had higher blood sugar levels than average had babies that weighed an average of 0.47 pounds more.

The women who had only one condition had large babies as well, but not as large. Obese mothers with no blood sugar issues had babies an average of 0.38 pounds heavier, and normal-sized moms with gestational diabetes had babies an average of 0.36 pounds heavier.

Women who are overweight and/or have higher blood sugar levels can pass along insulin resistance problems or higher blood sugar to their newborns, which puts those children at higher risk for obesity and diabetes.

"The big message from this is when you look at the impact of nutrition, metabolism and weight on pregnancy outcomes, every woman – on her first prenatal visit – should get a prescription for a session with a dietician and an appropriate healthy eating plan for her pregnancy," said Metzger. "This doesn't happen, but it should, and insurance companies should reimburse it."

The study was published in the April issue of Diabetes Care. The research was funded by the National Institutes of Health.

Reviewed by: 
Review Date: 
April 13, 2012
Last Updated:
April 16, 2012