Study finds link between autism and obesity during pregnancy


Pregnant women might now have one more good reason to watch their diet and exercise: A new study links autism and developmental delays in young children to metabolic conditions, like obesity and diabetes, in their mothers.

The findings, published in Monday’s edition of the journal Pediatrics, found that women who had diabetes or hypertension or were obese were 1.61 times as likely as healthy women to have children with autism spectrum disorders. They also were 2.35 times as likely to have children with developmental delays.

Child development experts said the findings were interesting but that it would be premature to suggest that the results could help explain the dramatic rise in diagnosed cases of autism over the last decade.

Last month, the Centers for Disease Control and Prevention reported that the autism rate among 8-year-olds in the U.S. had risen to 1 in 88, from 1 in 110 a few years earlier. Some of the change reflects a growing awareness of the disorder that leads to more diagnoses. Whether there is an actual increase in affected children is a source of great debate.

Several studies since the 1990s have indicated that there may be a link between diabetes in mothers and developmental delays in children. To further investigate this connection, a team of researchers led by UC Davis epidemiologist Paula Krakowiak looked at 1,004 California children ages 2 to 5 who were followed as part of an ongoing study of autism. Among them, 517 had autism spectrum disorders, 172 had developmental delays and 315 had shown typical development.

The study, called Childhood Autism Risks from Genetics and Environment, included data on the body mass index of the children’s mothers and whether they had conditions such as high blood pressure, Type 2 diabetes or gestational diabetes.

The researchers found that women who were obese were 1.67 times as likely as women who were not obese to have children with autism spectrum disorders, even after controlling for factors such as the mothers’ education, ethnicity and age when they gave birth.

In addition, obese mothers were slightly more than twice as likely to have children with developmental delays, meaning they lagged behind their peers in multiple areas on tests evaluating visual, motor, language and social skills.

Mothers who had Type 2 or gestational diabetes during pregnancy were 2.33 times as likely to have children with developmental delays.

The authors did not find a statistically significant relationship between diabetes and autism rates, however.

Other researchers were quick to point out that the study merely reported an association; it did not prove that obesity or diabetes contributed to autism.

“There’s a temptation to say, ‘Gee, we’ve got increased incidence of obesity and increased incidence of autism — there must be a strong connection between the two,’ ” said Andrew Adesman, chief of developmental and behavioral pediatrics at Steven and Alexandra Cohen Children’s Medical Center of New York, who was not involved in the study. “We really need to be careful of reading into it.”

Irva Hertz-Picciotto, an environmental epidemiologist at UC Davis and senior author of the paper, agreed that it would be “premature” to say that obesity in mothers caused autism in children. But if future work does back up the findings, she added, “the good part is, it’s modifiable. It can be controlled.”