The obesity epidemic may be contributing to the rising number of children diagnosed with autism, according to a study published Monday.

Researchers said mothers who are obese are significantly more likely to have a child with autism or another developmental abnormality. The finding adds to the increasingly complex picture of possible factors that contribute to the disorders.

About half the risk of autism, a condition characterized by poor social skills and repetitive behaviors, is genetic, researchers believe, while the rest stems from factors including older parental age, premature birth or failure to take prenatal vitamins.

The new findings come in the wake of the announcement last month by the U.S. Centers for Disease Control and Prevention that autism-spectrum disorders, as the range of abnormalities is now called, affect one in 88 U.S. children, up from one in 110 in a 2009 report.

The link between obesity and developmental disorders is particularly worrisome because obesity has become so prevalent. About a third of U.S. women of reproductive age are considered obese, the authors said.