But it's unlikely these factors cause the neurological condition, experts say,,,,
MONDAY, April 27 (HealthDay News) -- Children of older mothers and children who have breech deliveries are almost twice as likely to develop autism spectrum disorders (ASD), U.S. researchers report.
The findings confirm those of other studies and support the idea that much of autism has a genetic base, researchers say.
"A child with breech is twice as likely as a child who did not present as breech to develop autism," said lead researcher, Dr. Deborah Bilder, an assistant professor of psychiatry at the University of Utah School of Medicine.
A breech presentation occurs when the infant presents with the legs and buttocks first instead of the head. These children are usually delivered by cesarian section.
For mothers 35 and older, the risk that their child will develop ASD is 1.6 times greater than for children of younger women, and for women having their first child, the risk is 1.8 times higher than if she has delivered before, Bilder said.
The absolute risk for autism in any child is still relatively small, Bilder stressed. "I don't think there is good reason right now to instill worry in moms over 34 who are already concerned with other genetic issues," she said. "But I do think this is a finding to pursue further, because this suggests a potential genetic cause for autism."
There is no doubt that ASD runs in families, Bilder said. "I see a lot of families with autistic children, particularly in Utah where families are larger," she said.
But there may be other causes of autism, Bilder said. "We are also looking at environmental issues -- prenatally," she said.
The report is published in the May issue of Pediatrics.
For the study, Bilder's team collected data on eight-year-olds born in Utah in 1994 who were diagnosed with ASD in 2002 via the Autism and Development
All rights reserved