Avoid Excess Pregnancy Weight to Protect Your Unborn Baby’s Brain

Are you trying to get pregnant or expecting? Keep your weight at a health level. Obesity in pregnancy has health risks and may harm a developing baby’s brain.

If you are hoping to be pregnant soon, or already expecting, you likely know that weight gain is a normal part of pregnancy. However, gaining too much weight, or being significantly overweight to begin with, carries several health risks for pregnant women and, also, their babies.

Now, there’s even more reason for moms-to-be to work with their doctors to get and keep their weight at a healthy level.

Research from the NYU Grossman School of Medicine has found obesity in pregnancy could hinder the development of babies’ brains as early as the second trimester, potentially raising the risk of the children developing attention-deficit hyperactivy disorder (ADHD) and possibly autism. 

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Obesity in pregnancy carries risks

The majority of Americans are now overweight, and nearly half — 43 percent — are in the obese category, according to the Centers for Disease Control and Prevention (CDC). So, it’s no surprise that many women are significantly overweight when they are pregnant, increasing the odds of several health problems for both moms and babies.

For example, gaining more than the recommended amount of weight in pregnancy, or being obese when you become pregnant, is associated with having a baby who is born too large, which can lead to delivery complications, including a need for a cesarean delivery. There’s an increased risk for a baby born to an obese mom to develop obesity during childhood, too.

Gestational diabetes, a form or diabetes that only occurs during pregnancy, is more likely to occur if a woman is overweight. Studies also link excess weight during pregnancy with the development of preeclampsia (marked by extremely high blood pressure and sometimes kidney and liver damage), a condition potentially life-threatening to both a pregnant woman and her unborn child.

Because obesity rates are soaring in the U.S., it’s crucial to investigate other ways being significantly overweight while pregnant may impact a woman’s unborn child’s health over time. To that end, researchers at NYU Grossman School of Medicine zeroed in on the effects of expectant moms’ obesity on fetal brain development.

How a mom’s excess weight may affect an unborn baby’s brain

Previous studies have revealed a link between obesity in pregnancy and brain development, but they looked at cognitive function in children after birth. The NYU research, published in the Journal of Child Psychology and Psychiatry, however, is believed to be the first to document changes in fetal brain activity in the womb (as early as six months into pregnancy) in order to investigate the earliest possible negative effects of excess maternal weight on a developing baby’s brain.

The researchers recruited 109 women who were between six and nine months’ pregnant for the study. The women had body mass indexes (BMIs, a measure of body fat based on height and weight) ranging from 25 to 47. According to the National Institutes of Health, women with BMIs of 25 or more are considered overweight; BMIs of 30 or higher indicate obesity.

Using MRI imaging, the researchers measured and mapped fetal brain activity, specifically, the communication between large numbers of neurons (brain cells) clustered together in different parts of the brain.

In all, the researchers investigated 197 groups of metabolically active nerve cells in the fetal brain and then, using millions of computations, divided those groups into 16 meaningful subgroups of connections between groups of neurons. Next, the NYU team looked for any associations between the study volunteers’ weight and how the groups of neurons communicated with each other.

The results showed a statistically strong link between pregnant women who were obese and changes in two brain areas of their unborn babies — the prefrontal cortex and anterior insula. These regions of the brain are crucial to decision-making and behavior. Previous brain research has shown disruption in brain activity in these parts of the brain is linked to ADHD, autism, and overeating.

“Our findings affirm that a mother’s obesity may play a role in fetal brain development, which might explain some of the cognitive and metabolic health concerns seen in children born to mothers with higher BMI,” said researcher and NYU associate professor of child and adolescent psychiatry Moriah Thomason, PhD.

Bottom line? Avoid excess weight during your pregnancy

If you are overweight and trying to get pregnant, it makes sense to work with your doctor to get your weight under control before conceiving. But if you are already pregnant and overweight don’t panic. Do recognize, however, the importance of following your doctor’s nutrition advice and work to avoid any additional excess weight gain.

The investigators caution their research wasn’t designed to draw a direct line between fetal brain activity changes associated with overweight moms-to-be and any thinking or behavioral problems in toddlers or older children. The NYU team does, however, plan to follow the study participants over time to see if, in fact, children who showed brain activity changes before birth develop ADHD, behavioral problems, and other health problems.

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