Women who experienced physical, emotional or sexual abuse as children are more likely to have a child with autism than are women who were not abused, according to data from the Nurses Health Study II.
Those who experienced the most serious abuse had the highest likelihood of having a child with autism — 3.5 times higher than women who were not abused, reported researchers with the Harvard School of Public Health.
“Our study identifies a completely new risk factor for autism,” Andrea Roberts, PhD, the studys lead author and a research associate in the HSPH Department of Social and Behavioral Sciences, said in a news release. “Further research to understand how a womans experience of abuse is associated with autism in her children may help us better understand the causes of autism and identify preventable risk factors.”
The study, published March 20 on the website of JAMA Psychiatry (formerly the Archives of General Psychiatry), is described as the first to explore the relationship between a mothers exposure to childhood abuse and risk of autism in her children.
The authors examined data from more than 50,000 women enrolled in the Nurses Health Study II. They found it was not only women exposed to the most serious levels of abuse who had a higher risk of having a child with autism, but also a large number of women who experienced moderate abuse.
Women in the top 25% of abuse severity were 60% more likely to have a child with autism compared with women who did not experience abuse. These results suggest that childhood abuse is not only very harmful for the person who experiences it, but also may increase risk of disabilities in the next generation, the authors said.
Delving further, the researchers looked at nine pregnancy-related risk factors to investigate whether those factors were linked to a higher risk of having a child with autism in women who were abused as children. These nine risk factors — including gestational diabetes, preeclampsia and smoking — previously have been associated with an increased likelihood of having a child with autism.
The researchers found that women who had experienced abuse as children had a higher risk for each of the pregnancy-related risk factors that was examined. Surprisingly, however, those risk factors accounted for only 7% of the increased likelihood of having a child with autism among women who were abused.
Given that these factors accounted for so little of the association between a mothers experience of abuse and the risk of autism in her children, the authors speculated that other factors may play a role. One possibility is that long-lasting effects of abuse on womens biological systems, such as the immune system and stress-response system, are responsible for increasing their likelihood of having a child with autism.
More research is needed to tease out the mechanisms involved in the link between maternal childhood abuse and autism, the authors said.
The study abstract is available at http://archpsyc.jamanetwork.com/article.aspx?articleid=1666655.