Do Skinnier Moms Have Smarter Kids?

see larger photo

While it's true that overweight moms-to-be may have a few extra health concerns to contend with during pregnancy, should worrying about their child's future I.Q. scores be one of them?

That what's a new report from the UK—which says children born to overweight mothers may score slightly lower on I.Q. tests than kids with thinner moms—seems to imply. The study, conducted by University College London's Institute for Child Health, involved nearly 20,000 children who were tested on verbal ability, number skills and reasoning skills at the age 5 and again at age 7. IQ scores were about 1.5 points lower if the mom was overweight before becoming pregnant, and 3 points lower for children of moms whose weights were considered obese.

There are plenty of reasons why it's important for women to be as healthy as possible before becoming pregnant—and this includes maintaining a healthy weight. Overweight and obese moms may be more likely to develop gestational diabetes, high blood pressure, and more often deliver by c-section compared to other women.

But intelligence? It's an attention-getting headline, for sure. But, digging a little deeper, researchers admit they don't really know how—or even if—weight is involved. In this particular study, a difference of a few I.Q. points could be explained away as the result of the mothers' education or income levels. Or it could be due to a nutritional deficiency during pregnancy that ever-so-slightly affected the babies' brain development. If this is the case, the problem seems to be more about prenatal diet than what the scale says.

"Observational studies like this can never prove cause-and-effect," Dr. Ryan Van Lieshout, assistant professor of psychiatry and behavioral neurosciences at McMaster University in Hamilton, Ontario, tells HealthDay, after looking over the study results.

As lead author Emre Basatemur explains, "The association observed in our study accounts for a small amount of the overall variation seen in children's cognition." In other words, there are much bigger things out there that affect I.Q.

Holly Kipp, a plus-sized mom from Texas, lost some weight before becoming pregnant a few years ago, but still was considered overweight when she learned she was expecting. However, she didn't let this stop her from doing everything she could to have a healthy baby.

"I was overweight, yes, and I knew that this would put me at risk for gestational diabetes and some other complications, so very early on I tried my best to eat healthy and keep my pregnancy weight gain right at what my doctor and I discussed. My pregnancy was textbook and my son was born with a perfect 10 on his Apgar scores," she remembers.

And now that he's 6 years old and in first grade?

"He's straight As," says Kipp. "And reading at a third-grade level already."