Asthma or allergies in an expectant mother may increase the likelihood that her child will exhibit symptoms of autism, according to a Kaiser Permanente study featured in the Archives of Pediatrics and Adolescent Medicine's February issue.
The study also looked at the assumed association between autoimmune diseases such as lupus, diabetes, rheumatoid arthritis and Addison's disease and autism in the children of mothers with those conditions.
"With the exception of psoriasis, we did not find an association between autoimmune diseases in mothers and autism," says study author Lisa A. Croen, PhD, of Kaiser Permanente's Division of Research in Oakland, CA. "What we did find was a two-fold increase in autism among children of asthmatic mothers or women with allergies, particularly if their symptoms were medically diagnosed in the second trimester of pregnancy."
This association between a mother's asthma and allergies and a child's autism has not been reported in the medical literature previously, says Dr. Croen, and requires replication in further studies. Even with the increase in risk, Dr. Croen cautions that the risk of autism is still small, less than 1% even in children of women with asthma during pregnancy.
The study looked at more than 88,000 children born within the Kaiser Permanente population of Northern California between January 1995 and June 1999. From that group, 420 children between 3 and 7 years old were identified with diagnoses of autism. Those children were compared with a control group, children without a diagnosis of autism spectrum disorders.
Dr. Croen and her associates at Kaiser Permanente, the Department of Health Services in Oakland, CA, and the University of California at Davis found no association between autoimmune diseases in pregnant women and an increased risk of autism in their children, with the exception of psoriasis, which was associated with a doubling of risk. Asthma and allergies in expectant mothers were associated with 50% increase in risk of autism in their children.