By Sharon Kirkey, Postmedia News

Women who are obese during pregnancy are significantly more likely to have a child with autism than healthy-weight mothers, according to the latest research into the sobering risks of obesity during pregnancy.

A study of more than 1,000 children and their mothers published in the journal Pediatrics provides evidence that obesity and diabetes during pregnancy may be risk factors for autism spectrum disorder and other neurodevelopmental problems in childhood.

Conducted by researchers at the University of California, Davis, the study found obese women were 67-per-cent more likely to have a child with autism compared to healthy-weight mothers — a finding the authors warn could have severe health implications given ever-rising rates of obesity.

Obese mothers were also twice as likely to have a child with another developmental disorder.

Expressed another way, 21.5 per cent of the mothers of children with autism — and 23.8 per cent of mothers of children with another developmental disorder — were obese, compared to 14.3 per cent of mothers of normally developing children. Mothers with diabetes were found to have nearly twice the risk of having a child with developmental delays as healthy mothers.

In the U.S., nearly 60 per cent of women of child-bearing age (20-39) are overweight; one-third are obese, the research team wrote.

In Canada, 29 per cent of women are overweight, and 23 per cent are obese, according to Statistics Canada. Obesity rates have been climbing fastest for women aged 25-34, nearly doubling in the past 25 years.

Meanwhile, incidence of autism spectrum disorder, or ASD, appears to be increasing as well. About one in 110 children has the disorder.

Paula Krakowiak, the study’s lead author and a PhD candidate in epidemiology with the university’s MIND Institute, wondered whether there is a connection.

While autism’s cause is unknown, studies suggest its “pathogenesis” — the chain of events leading to the disorder — likely begins in the womb, she wrote. For the study, Krakowiak’s team analyzed data from roughly 1,000 children between the ages of two and five born in California between January 2003 and June 2010.

Of the children, 517 had autism; 172 had other developmental disorders and 315 children were developing normally.

The researchers conducted telephone interviews with the mothers and gathered information from their medical records, taking age at delivery, education level and other factors into account.

Overall, obesity, diabetes and high blood pressure were more prevalent among mothers of children with autism or other developmental disorders than the “control” group of normally developing children.

“That in itself was a surprising finding,” said Krakowiak.

However, the study does not prove cause and effect. Krakowiak stressed more research is needed to prove whether there is an association between obesity and other metabolic conditions during pregnancy and autism.

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