By Maria Cendejas

A new study says that children born to women who smoke during pregnancy are not at increased risk for autism,  Healthday News reports.

Smoking during pregnancy has been considered a possible cause of autism in children due to known links between smoking and behavioral disorders and obstetric complications, but the previous studies on how smoking during pregnancy affects risk of autism had mixed results.

Researchers examined data from about 4,000 Swedish children with autism and with a control group of 39,000 children without the condition.  The results showed that 19.8% of the children in the autism group and 18.4 % of those in the control group had mothers who smoked during pregnancy. The difference was not statistically significant.

The study was published online in December 2011 in the Journal of Autism and Developmental Disorders.

"We found no evidence that maternal smoking during pregnancy increases the risk of autism spectrum disorders. Past studies that showed an association were most likely influenced by social and demographic factors such as income and occupation that have associations with both the likelihood of smoking and with the rate of autism spectrum disorders," study leader Dr. Brian Lee, an epidemiologist at the School of Public Health at Drexel University in Philadelphia. 

Lee said,“ The findings help reassure mothers who smoked during pregnancy that their behavior likely didn't cause their child's autism and crosses off another suspect on the list of possible environmental risk factors for ASD."

He reminded women that smoking during pregnancy is unhealthy and has known risks for their children.

The study results do not suggest that pregnant women can smoke during pregnancy without causing any health issue.  They suggest that smoking during pregnancy is not the cause for autism.

Smoking during pregnancy is more than unhealthy to the baby and pregnant woman.  International Agency For Research On Cancer (IARC) has classified environmental tobacco smoke as carcinogenic to humans based on sufficient evidence in humans. The U.S. National Toxicology Program has classified it as known to be a human carcinogen since the 9th RoC (2000).  This means that smoking may not cause any acute disease, but increases risk for cancer to say the least.

The rate of autism has been on the rise.  A couple of decades ago, autism was rare.  But one out of 100 children today may be diagnosed with this mental condition.