Secondhand Smoke and the Unborn Baby

Secondhand smoke during pregnancy linked to child behavioral problems

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) So it's pretty clear that smoking while pregnant is a bad idea. But what if it's just those around you who are smoking? Does that affect unborn babies too? Possibly.

A recent study found exposure to secondhand smoke during pregnancy is linked to behavioral problems in the children later on.

Children whose mothers were exposed to secondhand smoke were twice as likely to act out with behavioral issues.

"Pregnant? Avoid secondhand smoke."

The study, led by Jianghong Liu, from the School of Nursing at the University of Pennsylvania, aimed to uncover any possible links between secondhand smoke during pregnancy and child behavior issues. The researchers looked at data from 646 mothers and their children enrolled in a study group in China.

First, the researchers assessed how much tobacco smoke the women had been exposed to at home, at work and at other common places during their pregnancy. Then the researchers assessed the children's behavior at age 5 to 6.

Overall, 37 percent of the women reported exposure to secondhand smoke while they were pregnant. More of the children of these women had notable behavior problems compared to the children of women who were not exposed to secondhand smoke.

Overall, 25 percent of the kids born to moms who were around secondhand smoke while pregnant had problems with acting out and overall behavioral issues, compared to 16 percent of the children whose moms were not around tobacco smoke during pregnancy.

However, once the researchers took into account the children's gender and parent demographics, such as income, mental health history, job and level of education, the link to overall behavioral problems evened out.

The only association the researchers found after adjustments was between secondhand smoke during pregnancy and higher rates of "externalizing" behavioral problems in the children. Externalizing problems refer to behavior issues like acting out, aggression, rule-breaking and hyperactivity.

But the researchers did not find that the behavior problems got worse based on how much secondhand smoke their mothers were exposed to. The link was simply an association between exposure during pregnancy to secondhand smoke (on a regular basis) and behavioral difficulties in the children as grade schoolers.

“The key message for pregnant women is to protect their growing fetus from exposure to secondhand smoke," said Dr. Liu in a release about the study.

The study was published November 23 in the journal Neurotoxicology. The research was funded by the National Institute of Environment Health Sciences. The authors declared no conflicts of interest.

Reviewed by: 
Review Date: 
December 6, 2012
Last Updated:
December 11, 2012