Mom’s pregnancy weight may increase risk of autism, developmental disorders

A mother’s weight and metabolic conditions during pregnancy are not just potentially harmful to herself – new research suggests these factors can play a key role in her child’s development as well.

A major study conducted by researchers at the University of California, Davis MIND Institute revealed that mothers who are diabetic or obese while pregnant had a significantly increased risk of having a child with autism or developmental delays compared to pregnant women of normal weight without diabetes.

While previous studies have been conducted on a possible link between diabetes and a risk of autism, the authors said this is the first study to expand on maternal metabolic conditions to include both obesity and hypertension.  According to the researchers, the results bring the scientific community one step further in understanding how a child’s environment plays a role in the progression of developmental disabilities.

“This study was investigating environmental conditions that could affect the developing child during the gestational period,” said Dr. Irva Hertz-Picciotto, a professor of public health sciences at UC Davis and senior author of the study.  “Usually when you think of environment you think of pollution or chemicals, but environment is very broad.  Anything that is not genetic, we consider environmental – so this can include infections, diet, and nutrition.  It also includes the health of the mother, because while the fetus is developing, that’s the environment that it’s in.”

Hertz-Piciotto and her colleagues examined 1,004 mother and child pairs.  Each pair was separated into one of three groups depending on if the child had autism, developmental delays, or was developing normally.  Once categorized, the researchers conducted lengthy interviews with the children’s mothers about their medical conditions during pregnancy, cross-checking the mother’s answers with medical records from their physicians.

Compared to women of normal weight, the women who were obese during pregnancy were 1.66 times more likely to have a child with autism. The likelihood that these women had children with developmental delays was even higher – more than double the chance.

Mothers who were diabetic during their pregnancies had a 2.33 times greater chance of having a child with a developmental disorder than moms without the condition.  While these women also had a greater chance of having autistic children, the results were not statistically significant.

Even if children with obese mothers weren’t autistic or did not have a developmental problem, they still had a likelihood of being behind in their classes.

“We also looked at all of the children and looked at their scores in terms of language development,” Hertz-Piciotto said.  “We did different measures of intellectual capacity and found that in general, moms who had these [weight and metabolic] conditions - their children tended to score a little bit lower.  So, it might indicate a general dampening of how the brain is developing.”

The results of this study are significant considering the increase in America’s obesity rates.  According to the Centers for Disease Control and Prevention (CDC), more than 60 percent of women of childbearing age in the U.S. are overweight, while more than 31 percent of them are obese.  Obesity during pregnancy is becoming a very common condition, affecting one in five women.

And obesity isn’t the only condition on the rise.  The CDC recently released an estimate that autism spectrum disorders (ASD) affect one in 88 children in the United States – the highest prevalence to date.

With such staggering statistics, scientists are frequently trying to reduce these figures.  While maintaining a healthy weight during pregnancy will not completely remove the risk of having an autistic or developmentally challenged child, the researchers suggest that eliminating one potential factor could possibly save a child from living with a learning disorder.

“The causes of autism are multi-factorial, there isn’t going to be one umbrella cause,” Hertz-Piciotto said.  “Not every obese mom has a child who develops autism, so it’s probably in combination with other factors.   But we do have a lot of adaptive mechanisms, so if you take away one possible cause, maybe the baby’s body is able to handle it.”

Hertz-Piciotto hopes that this research will encourage the creation of a progressive study, in which researchers follow women throughout their pregnancies while taking blood samples each step of the way.  A progressive study would help to truly establish whether or not there is a causal relationship between a mother’s weight and developmental delay.

But until then, Hertz-Piciotto cautions women to be more attentive to their diet and health during those nine months of pregnancy – just in case.

“It’s beneficial to her health, and it’s beneficial to her children as well,” Hertz-Piciotto said.  “That prenatal gestational period – plan for it, and put yourself in the best health at the start.”