Smoking during pregnancy-it's bad behavior

By Lorraine Cichowski and Judy Silberg

RICHMOND, Va. – For years, researchers have documented the dangers of smoking during pregnancy -- smaller babies, premature deliveries, infant deaths and sudden death syndrome, to name just a few risks associated with smoking by pregnant women. 

But a pregnant mother’s smoking can’t necessarily be blamed directly for causing behavioral problems later in her adolescent children, as some studies have suggested.

Researchers at Virginia Commonwealth University say her own antisocial behavior may cause a mother to smoke during pregnancy, and that antisocial tendency is passed on to her children, causing subsequent conduct problems.

The study, reported in the Jan. 15 issue of Biological Psychiatry, challenges previous findings that suggested exposure to smoke in the womb causes adolescents, particularly boys, to have conduct disturbance – a repetitive and persistent pattern of serious misbehavior that causes problems in the child’s school and family life. It can include fighting, physical cruelty to people and animals, deliberate destruction of property by fire or other means, lying, theft and other belligerent, threatening or disobedient behavior.

“Smoking during pregnancy causes many health problems for the fetus and child and is inadvisable. However, our study shows that it does not necessarily have a direct effect on the development of behavioral problems in adolescence,” said Judy L. Silberg, Ph.D., assistant professor of human genetics and a researcher at the Virginia Institute for Psychiatric and Behavioral Genetics at VCU. “The mother’s own symptoms of childhood conduct disturbance are more related to her child’s behavioral problems than her smoking.”

Dr. Silberg and her colleagues used family data collected on 538 adolescent twin boys, aged 12-17, who participated in the Virginia Twin Study of Adolescent Behavioral Development, an ongoing 15-year study designed to understand the role of genetic and social factors in the development of psychiatric problems in children and adolescents. Their statistical analysis found that a child’s tendency to have conduct disturbance was related more to the mother’s own behavioral problems as a youth than it was to the mother’s smoking during pregnancy.

“These results suggest that the observed association between maternal smoking and juvenile conduct disturbance may be explained by the transmission of antisocialism and not the direct effect of smoking itself,” Silberg said.

Silberg said additional research is needed to show whether the antisocial tendency is passed from mother to son genetically or whether it is a result of the family environment.