Interestingly, the same 2 percent prevalence of autism is exactly what Roberts found for the children of women who had been abused in childhood.
Roberts' team collected data on more than 50,000 women who took part in the Nurses' Health Study II.
Although not many of these women experienced severe abuse as children, many were moderately abused, the researchers found.
In fact, only about 2 percent of the women said they had experienced severe abuse, yet even the women in the top 25 percent of those who experienced moderate levels of abuse had a 60 percent chance of having a child with autism, they noted.
To be sure abuse was a critical factor, Roberts' group looked at other risk factors known to be associated with autism, including diabetes during pregnancy, high blood pressure during pregnancy (preeclampsia) and smoking.
Although the abused women did have a higher risk of experiencing one of these other risk factors, it accounted for only 7 percent of their increased odds of having a child with autism, the investigators found.
The researchers speculate that the long-lasting effects of abuse on their immune system and stress-response system might be responsible.
Another expert, Dr. Roberto Tuchman, director of the autism and neurodevelopment program at Miami Children's Hospital Dan Marino Center, thinks the importance of this study is that it pinpoints another group of children who might be at risk for autism.
"The study has identified an at-risk population," he said. "This is a population we should be more aware of as being in need of early identification and intervention."
For more on autism, visit the U.S. National Library of M
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