While the researchers are quick to point out that their study doesn’t conclude that obesity during pregnancy causes autism but that their findings raise a red flag and warrant further research.
Researchers at the University of California, Davis, looked at 1,004 children aged 2 to 5 years enrolled in the CHARGE (Childhood Autism Risks from Genetics and the Environment) study from 2003 to 2010.
Obese mothers were 67% more likely than mothers of normal weight and with no metabolic disorders to have a child with autism, and they were more than twice as likely to have a child with another developmental disorder — a delay in speech delay, perhaps, or a failure to reach developmental milestones at the appropriate age.
Mothers of children who were not developing typically were more likely to be obese: 21.5% of mothers of children with autism and 23.8% of mothers of children with developmental delays were obese, versus 14.3% of moms of typically developing children.
“Our findings raise concerns that these maternal conditions may be associated with neurodevelopmental problems in children and therefore could have serious public health implications.” the study authors wrote in their report published today in the journal Pediatrics.
“It’s hard to say if they’re linked,” said study author Irva Hertz-Picciotto, professor of public health sciences at the University of California at Davis. “It might be there’s some environmental factor that contributes both to the obesity epidemic and to the rise in autism cases. Or it could be the increase in obesity is, in fact, contributing to the increase in autism. But it’s certainly not going to account for all of it.”
Hertz-Picciotto and colleagues have also linked autism to poor maternal nutrition, antidepressant use and closely spaced pregnancies.
How obesity and diabetes during pregnancy might predispose the developing fetus autism is unclear, but theories include overexposure to glucose, insulin and inflammation.
“This study doesn’t tell you anything about the origin of autism. What it does tell you are things associated with autism,” said Dr. Susan Hyman, associate professor of pediatrics at the University of Rochester Medical Center. “We would not advocate treating the hypothetical causes of autism, but we would recommend women of childbearing years to eat healthy and exercise and take care of themselves, not only for the fetus but so they can see their children grow up.”
Hyman said autism is a complex condition thought to emerge from an interaction of multiple genetic and environmental influences.
Dr. Ari Brown, an Austin, Texas-based pediatrician, said the study is one more piece in the puzzle of autism spectrum disorders, a collection of conditions with varying symptoms and, quite likely, multiples causes.
“I think we’re just beginning to unravel some of the mysteries of autism spectrum disorders. And I don’t think we’re going to find just one answer because it’s not just one disease,” Brown said. “But it’s really important for women prior to do a preconception visit with their doctor and talk about attaining ideal body weight prior to becoming pregnant. Being overweight or obese can lead to a variety of health problems for mom and baby.”