Women who smoke in pregnancy may be more likely to have a child with high-functioning autism, such as Asperger’s disorder, according to preliminary findings from a study by researchers involved in the US autism surveillance program of the Centers for Disease Control and Prevention (CDC).

"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, PhD, MPH, lead author of the study and assistant professor in the University of Wisconsin-Milwaukee’s Joseph J. Zilber School of Public Health. “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.”

The study was published in the journal Environmental Health Perspectives.

Smoking during pregnancy is still common in the United States despite its known harmful impacts on babies. The researchers found that 13% of mothers whose children were included in the study had smoked during pregnancy.

The population-based study compared smoking data from birth certificates of thousands of children from 11 states to a database of children diagnosed with autism maintained by the CDC’s Autism and Developmental Disabilities Monitoring Network (ADDMN). Of the 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,” says Kalkbrenner. “But it does say that if there is an association, it’s between smoking and certain types of autism,” implicating the disorders on the autism spectrum that are less severe and allow children to function at a higher level. That connection, she adds, needs further study.

Because autism involves a broad spectrum of conditions and the interplay of genetics and environment is so complex, no one study can explain all the causes of autism, she adds. “The goal of this work is to help provide a piece of the puzzle. And in this we were successful.”

Source: University of Wisconsin-Milwaukee