Utah researchers have found a connection between autism and pregnancies in which the mother is 35 and older, or having her first child, or whose baby presents breech.
In a study to be published in the May issue of Pediatrics, the Utahns said the three seperate risk factors may provide clues to the causes of autism spectrum disorders, marked by problems communicating, difficulty with social interactions and unusual or repetitive activities.
But parents whose infants were born under such circumstances shouldn't worry their children will become autistic, said Deborah Bilder, lead author of the study and a psychiatrist who treats autistic children at the University of Utah Neurobehavior Home Program.
For example, "The vast majority of children who are born breech are completely healthy," she said in an interview.
Parents might take heart in knowing researchers are hunting for the underlying cause for the disorder, particularly in Utah, with its higher than average rate of autism.
"Ultimately, what we want to come up with is something we can treat, something we can prevent. We're far from that," said Bilder, noting that the new study is one step toward that goal.
South Jordan mother Amanda Patten, 35, wasn't aware of the research. But she's interested because she has two sons with autism, and their new 3-month old brother presented breech. She had already planned to carefully monitor whether her youngest was meeting his milestones. The study will make her even more vigilant, she said.
To parents who are worried, she tells them to trust their instincts: "Really push it with their pediatricians and make sure they're heard."
Bilder, along with Judith Zimmerman, Judith Miller and William McMahon, who all work in the U.'s psychiatry department, came to the study's conclusions by analyzing the birth certificates of 132 Utah 8-year-olds who were diagnosed with autism in 2002. Those records were compared to 13,200 Utah children without the diagnosis.
Other researchers have found the same connections between birth characteristics and autism -- and others, including low birthweight and advanced paternal age -- but the Utahns say their study is stronger because it included children with more types of autism. Still, they believe it needs to be replicated.
The study says the risk factors they found are "difficult to explain" on their own. Some explanations include:
» An overrepresentation of first-born children because their parents were reluctant to have another child;
» Changes to the genome as women age, providing further evidence of a genetic predisposition to autism;
» Some autistic children have neuro-muscular abnormalities present before birth that also prevent them from entering the birth canal head first.
"Something that may be causing the breech can also be causing the development of autism," said Bilder, who said researchers could use the findings to look for other similarities among autistic children who presented breech to find the cause.
