Study: Mom’s weight may be factor in autism

Posted at 6:40 AM, Apr 09, 2012
and last updated 2012-04-09 21:34:03-04

By Val Willingham
(CNN) -- A mother's weight and diabetic condition may increase the risk of her unborn child developing a neurodevelopmental disorder, such as autism, according to a new study published in this week's journal Pediatrics.

Researchers with the UC Davis MIND Institute in California found that mothers-to-be who were obese were 67% more likely to have a child with autism as opposed to normal-weight mothers without diabetes or hypertension. And a pregnant woman who is obese doubles her child's risk of having another developmental disorder (poor communication skills, lack of attention) compared to a child born to a mother at healthy weight.

The study included 1,004 mother-and-child pairs who were enrolled in the Childhood Autism Risks from Genetics and the Environment Study (CHARGE). Most of the families were from Northern California, with a small group living in Los Angeles. The children were between 24 and 60 months old; 517 children had autism; 172 with other developmental disorders; and 315 were developing normally. The participants were enrolled between January 2003 and June 2010.

When it came to women with diabetes, researchers discovered they had more than two times the chance of having a child with developmental delays as opposed to those without diabetes.

"I was surprised at how strong the obesity effect was on new-born children and their cognitive development," said Dr. Irva Hertz-Picciotto, professor of Epidemiology and a researcher at the MIND Institute . "And we didn't just look at weight," she continued. "We looked at diabetes, and hypertension in mothers to see how those conditions affected their children. It was pretty significant."

The study also found that children with autism who were born to diabetic mothers had greater deficits in communication skills than the children with autism born to healthy mothers. Yet, many children who were not diagnosed with autism, but had diabetic mothers, also showed some signs of socialization problems as well as poor communication skills, compared to the non-autistic children of healthy women.

"Over a third of U.S. women in their childbearing years are obese and nearly one-tenth have gestational or type 2 diabetes during pregnancy," said Paula Krakowiak, a biostatician with the MIND Institute. "Our finding that these maternal conditions may be linked with neurodevelopment problems in children raises concerns and therefore may have serious public-health implications."

For more than a decade researchers have been looking for a genetic cause for autism. But new research suggests multiple genetic mutations make a child susceptible for the disorder. But in recent years, scientists have also been looking for environmental triggers that push these genetically susceptible children over the edge. As the search for these triggers continues, this research seems to suggest obesity may be one of those triggers in some cases.

Its authors say this is the first study to examine associations between neurodevelopmental disorders and maternal metabolic conditions. According to the Centers for Disease Control and Prevention, more than 60% of U.S. women of childbearing age are overweight, 34% are obese, and 16% have metabolic syndrome, a precursor to diabetes. Nearly 9% of U.S.women of childbearing age are diabetic, and more than 1% of U.S. pregnancies are complicated because the mother has high blood pressure.

Obesity is a major risk factor for diabetes and hypertension and can increase insulin resistance and inflammation in the body. Study authors suggest in women with diabetes, unregulated sugar in the body can result in prolonged fetal exposure to high glucose levels which doctors say can affect brain development in unborn children.

"The fetus depends on the mother for nutrients," noted Dr. Hertz-Picciotto. "So at certain times in the fetal development if sugar levels or other nutrients are too high or too low, the imbalance can affect the fetus, especially when it comes to the brain."

But Hertz-Picciotto said there was good news from this study.

"The best thing about this is a lot of this can be modified," she said. "If you are thinking about getting pregnant, watch your weight and if you have diabetes have your doctor keep a close eye on you so you keep your glucose under control while you're carrying your baby."