Pregnant And Obese? Your Son’s IQ And Development Will Suffer

We all want to give our children every advantage in life. Good health is crucial. We want our children to grow up strong and healthy.

Positive emotional health is important, too. We want them to be well-adjusted and ready to take on the challenges of life.

Of course, when it comes to taking on life’s challenges, we want to make sure our children are intelligent, well-educated and capable of making sound and positive decisions.

It seems that sons born to obese mothers may be behind the 8 ball on that last part, the intelligence factor. If mom is obese while pregnant, it can impact her child’s development, especially motor skills and in particular for boys, IQ.

Researchers working out of Columbia University Mailman School of Public Health and the University of Texas at Austin have published a study in BMC Pediatrics that says just that. Severely obese pregnancies lead to lagging motor skills in preschoolers and lower IQ during middle childhood for boys. Their work revealed that the differences are comparable to the impact of lead exposure in early childhood.

While no IQ differences were noted in girls, what the researchers found regarding motor skills for all children and IQ development for boys born to mothers who were obese during pregnancy is profound. They studied 368 mothers and their children during pregnancy and then when the kids turned 3 and 7 years old. All came from similar socioeconomic circumstances and neighborhoods.

The scientists found that the children of mothers who were obese during pregnancy had lower motor skills at age 3. When they measured the children again at age 7, they found that maternal obesity was linked to lower IQ scores for the boys – by 5 or more points – compared to sons born to normal-weight mothers.

“What’s striking is, even using different age-appropriate developmental assessments, we found these associations in both early and middle childhood, meaning these effects persist over time,” said Elizabeth Widen, assistant professor of nutritional sciences at UT Austin and a co-author. “These findings aren’t meant to shame or scare anyone. We are just beginning to understand some of these interactions between mothers’ weight and the health of their babies.”


While previous research has linked certain pre-natal dietary practices, such as eating more of certain fatty acids found in fish, was linked to higher IQ scores for those children, it’s not clear why prenatal obesity would negatively effect children’s motor skills and boys IQ later. It’s possible that the metabolic symptoms of obesity – metabolic stress, hormonal disruptions, high levels of glucose and insulin and inflammation – may also affect fetal development. Dietary and behavioral differences may also be factors.

In order to ensure the accuracy of results, the researchers controlled for a number of factors that may have otherwise given the children a prenatal developmental advantage. While diet and breastfeeding habits were not included in controls, marital status, race, ethnicity, mother’s education level and IQ and whether the child was born prematurely were included. Also included was whether the children were exposed to toxic chemicals like high air pollution levels during gestation.

They also followed up and accounted for whether the child’s home environment was nurturing. Researchers looked at parental interaction with their children and whether the child was provided with books and toys. Nurturing home environments were found to reduce the negative impacts of prenatal maternal obesity.

According to Widen and senior author Andrew Rundle, DrPH, associate professor of Epidemiology at Columbia Mailman School, while the results showed that the effect on IQ was smaller in nurturing home environments, it was still there.

This isn’t the first time that research has indicated that boys may be more vulnerable to developmental problems in utero than girls. Earlier studies on prenatal maternal lead exposure found lower IQ performance in boys, but not girls, whose mothers were exposed to lead while carrying their children. A 2019 study indicated that in mothers who had been exposed to fluoride during pregnancy were more likely to have sons who scored lower on an IQ assessment.

The affect of prenatal exposures and conditions on IQ is important, since childhood IQ is a key predictor of education levels, socio-economic status and professional status later in life. It’s widely believed that there is the potential for the impact of these developmental disturbances to last into adulthood.

Based on their findings, the researchers offered some common-sense advice to obese or overweight women who get pregnant. It includes the old saw about eating a well-balanced diet rich in vegetables and fruits. Solid advice for anyone.

They also suggest taking a prenatal vitamin, staying active and making sure to get enough fatty acids such as the kind found in fish oil. (I advise my clients, pregnant or not, to take Krill Oil. The best is JayLab Pro Omega Icon.)

After the children are born, suggests the research team, a nurturing home environment matters. Regular doctor visits (both pre- and postnatal) are also important, and weight gain should be addressed. The doctor should be able to provide guidance on both the mother’s health and the baby’s development. If he or she can’t, perhaps finding a new doctor should be part of the prenatal plan.

Keep the faith and keep after it!

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Journal Reference – Elizabeth M. Widen, Amy R. Nichols, Linda G. Kahn, Pam Factor-Litvak, Beverly J. Insel, Lori Hoepner, Sara M. Dube, Virginia Rauh, Frederica Perera, Andrew Rundle. Prepregnancy obesity is associated with cognitive outcomes in boys in a low-income, multiethnic birth cohort. BMC Pediatrics, 2019

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