You may have heard that too little weight gain during pregnancy—or too much—can genetically program a fetus for future obesity. Or that being obese can increase a pregnant woman’s risk of gestational diabetes, blood clots and miscarriage. Now researchers at Wake Forest University have found yet another danger associated with excess weight and pregnancy: It could negatively affect a developing baby’s brain.
In a new study published in the journal Pediatrics, researchers looked at cognitive development problems in premature babies. Of the 921 premature infants studied, about 11% were still cognitively impaired at age 2. And those children whose mothers were obese pre-pregnancy were twice as likely to have these cognitive issues as the babies born to normal-weight mothers.
“This study shows that obesity doesn’t just affect the mother’s health, but might also affect the development of the baby,” said Dr. Jennifer Helderman, an assistant professor of pediatrics at Wake Forest University.
It’s not exactly clear why obese mothers were more likely to have cognitively-impaired babies, but the leading theory involves inflammation, according to Helderman. Obesity has been linked to inflammation, and inflammation can damage the brain. Whether obesity-related inflammation in moms can be passed to fetuses remains unknown.
While it may seem counterintuitive to make a big weight-loss push before getting pregnant (what, lose weight just to gain it all back?) it could actually be very important, for both maternal and fetal health. “We’re not saying that weight loss or that maintaining a healthy weight is easy,” Helderman told Time, “but for mothers who are interested in doing everything they can for a healthy pregnancy and a healthy baby, this might be one area they want to target.”