While it is important to gain a healthy amount of weight during pregnancy, studies have shown that during pregnancy, obesity — when an individual's body mass index is 30 or higher — can have especially negative impacts for mothers. Now, new research suggests that is also harmful to babies. Findings from a new study even link obesity during pregnancy with birth defects.
The study, published by The BMJ, pulled from a large sampling of over 1 million women in order to observe the correlation, and potential causation, between weight during pregnancy and risk of birth defects. According to the study's findings, 3.4 percent of women who were classified as underweight or found to be within the healthy weight range during their pregnancies went on to give birth to babies with malformations. Of the women placed in the overweight group, 3.5 percent gave birth to babies with congenital defects.
Researchers then further divided women placed in the "obese" range into the three categories based on body mass index. The class 1 group, those who had BMIs between 30 and 45, had a 3.8 percent rate of babies with congenital defects. The rate of defects increased to 4.2 percent among the second obesity class, moms with BMIs between 35 and 40. Finally, in the obesity class 3 group, made up of mothers with BMI ratings of over 40, offspring had a 4.7 rate of birth defects.
There is good news for moms who struggle to maintain a healthy weight during their pregnancies. The new findings suggest that even small changes to BMI can positively impact the health of babies, easing a bit of the pressure to drop large amounts of weight while pregnant.
This study is not the first to suggest a connection between being overweight during pregnancy and birth defect rates. The risk of spina bifida is twice as high for children of obese women as for those with mothers within a healthy weight range, according to a February 2009 study published in the Journal of the American Medical Association. Similarly, the risks of a baby having a cleft lip, heart defects, or hydrocephalus is substantially higher.
Being obese while pregnant has also been linked to a number of health risks for moms, many of which can complicate pregnancies: It can increase a woman's risk of contracting gestational diabetes, preeclampsia, and infection, and can also increase the risk of pregnancy loss or need for a c-section.
The recent findings on obesity and birth defects are further reason to consult your doctor while pregnant to best gauge what your goal weight-gain should be. Because when women continue to learn about the factors contributing to their fetus' health during pregnancy, they're empowered to make smarter decisions about their own health, too.