UC Davis Health System, Associated Press
In this undated photo provided by the UC Davis Health System, Irva Hertz-Picciotto is shown. Irva Hertz-Picciotto, a researcher at the University of California, Davis, is leading a study into what sparks autism disorders. More than $1 billion has been spent over the past decade searching for autism’s causes.

Related article: After $1B, experts see progress on autism's causes

Women who are obese during pregnancy may be more likely to have a child with autism, according to new research published Monday online in the journal Pediatrics. And babies born to women with diabetes could be more apt to have a child with other developmental delays.

The researchers, from the University of California-Davis MIND Institute, are careful to note that the study doesn't prove that obesity or diabetes cause autism spectrum disorders (ASDs) or other developmental delays. But they say it provides yet another reason to be concerned by the increasing level of obesity in America.

The Associated Press called this one of the first studies linking autism and obesity. It said that women typically face a 1 in 88 chance of having a child with autism and the study results "suggest that obesity during pregnancy would increase that to a 1 in 53 chance."

Previous research had noted links between obesity in pregnancy and stillbirths, preterm births and some birth defects. Other studies had documented an association between maternal diabetes and general developmental impairments, but the UC Davis researchers were interested in connections between autism and metabolic disorders during pregnancy, including hypertension, diabetes and obesity. They found that moms who were obese were 67 percent more likely to have autistic children than moms who were not overweight.

"The brain is quintessentially susceptible to everything that's happening in the mother's body," Irva Hertz-Picciotto, senior author of the study and chief of the division of environmental and occupational health in public health sciences at UC Davis, told the Wall Street Journal. But "no one factor is going to be responsible for any one child's case. This is not a 'blame the mom' thing."

The researchers also found that children of moms with diabetes who had autism "had greater deficits in language comprehension and production and adaptive communication" than children with autism spectrum disorders who were born to healthy moms. The children of diabetic moms who had no sign of autism "exhibited impairments" in socialization and in language comprehension and production seen less often in children without autism born to healthy moms, according to a UC Davis release that accompanied the study.

More than one-third of American women of childbearing age are obese and almost 10 percent have gestational or type 2 diabetes during pregnancy, said Paula Krakowiak, one of the researchers. "Our finding that these maternal conditions may be linked with neurodevelopmental problems in children raises concerns and therefore may have serious public health implications. ... It suggests that fetal exposure to elevated glucose and maternal inflammation levels adversely affect fetal development."

According to the Centers for Disease Control and Prevention, anyone with a body mass index of 30 or higher is considered obese. More than 60 percent of women of childbearing age are overweight, while 34 percent are actually obese. It says 16 percent have metabolic syndrome.

For the study, the researchers looked at 1,004 mother/child pairs from different backgrounds in California who were enrolled in the Childhood Autism Risks from Genetics and the Environment Study. The children were 2-5 years old. Of those, 517 children had ASD, 172 had some other developmental disorder and 315 were developing with no apparent disorder.

Dr. Daniel Coury, chief of developmental and behavioral pediatrics at Nationwide Children's Hospital in Columbus, Ohio, told Lindsey Turner of the Associated Press that the results "raise quite a concern." He said obesity rates and autism rates in America have occurrred in tandem and that may not be coincindence. But he said if the link holds, it would be "only one of many contributing factors."

The researchers didn't find any difference based on race, ethnicity, educational attainment or health insurance status. The National Institutes of Health helped fund the research.

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