Pregnant women who smoke may be at higher risk for having a child with high-functioning autism, such as Asperger’s disorder, according to preliminary study findings by researchers involved in the U.S. Autism Surveillance Program of the Centers for Disease Control and Prevention.
“It has long been known that autism is an umbrella term for a wide range of disorders that impair social and communication skills,” says Amy Kalkbrenner, assistant professor in the University of Wisconsin-Milwaukee’s Joseph J. Zilber School of Public Health, lead author of the study.
“What we are seeing is that some disorders on the autism spectrum, more than others, may be influenced by a factor such as whether a mother smokes during pregnancy.”
Despite the well-known harmful impact on babies, smoking during pregnancy is still common in the U.S. About 13 percent of mothers in the study had smoked during pregnancy.
The population-based study looked at smoking data from birth certificates of thousands of children from 11 states and compared it to a database of children diagnosed with autism from the CDC’s Autism and Developmental Disabilities Monitoring Network (ADDMN).
Out of 633,989 children born in 1992, 1994, 1996 and 1998, 3,315 were identified as having an autism spectrum disorder at age 8.
“The study doesn’t say for certain that smoking is a risk factor for autism,” Kalkbrenner says. “But it does say that if there is an association, it’s between smoking and certain types of autism,” pointing toward disorders on the autism spectrum that are less severe and allow children to function at a higher level.
That connection needs further study, she adds.
Because of the wide spectrum of conditions and complex interplay of genetics and environment in autism, no one study can explain all cases of autism, said Kalkbrenner. “The goal of this work is to help provide a piece of the puzzle. And in this we were successful.”
The study is published in the journal Environmental Health Perspectives.