Mother's environmental tobacco smoke exposure during pregnancy and externalizing behavior problems in children

While the impact of active maternal smoking during pregnancy on child health has been well investigated, the association between maternal passive smoking, or environmental tobacco smoke (ETS), or second-hand smoke, and behavioral development of offspring is less clear. This study examines the association between maternal ETS exposure during pregnancy and child behavior problems.

Cross-sectional data of 646 mother-child pairs from the Jintan China Cohort Study were used in the analyses. Mother's exposure to tobacco smoking at home, the workplace, and other places during pregnancy (for the determination of maternal ETS exposure) and children's behaviors (via Child Behavior Checklist) were assessed when the children were 5-6 years old. Logistic regression models were constructed to examine associations between maternal exposure to ETS during pregnancy and internalizing and externalizing behavior problems, adjusting for potential cofounders including child sex and parental characteristics.

37% of mothers reported ETS during pregnancy. Children of mothers exposed to ETS during pregnancy had higher scores for externalizing and total behavior problems, with 25% of children whose mothers were exposed to ETS compared to 16% of children of unexposed mothers. After adjusting for potential confounders, ETS exposure was associated with a higher risk of externalizing behavior problems in offspring of exposed mothers (OR=2.08, 95% confidence interval [CI] 1.27-3.43). Analysis after multiple imputations and sensitivity analysis further verified the association, but no dose-response relationship was found. ETS exposure, however, was not associated with internalizing or total behavior problems.

This study suggests that maternal ETS exposure during pregnancy may impact child behavioral development, particularly externalizing behaviors.