Numerous studies have tested associations between maternal smoking during pregnancy and subsequent problems of the offspring. However, most such studies have assessed a narrow range of problems at relatively young ages. A team of Dutch researchers tested relations between prenatal exposure to tobacco smoke and the CBCL Internalizing and Externalizing scores of a general population sample of 396 children at ages 5, 10 to 11, and 18 years (Ashford et al., 2008).
Because maternal smoking may be associated with other risk factors, the researchers used latent growth curve modeling that controlled for maternal illness before and during pregnancy, pregnancy duration, complications during pregnancy, child birth weight, and maternal psychopathology, which was assessed via the Young Adult Self-Report (the predecessor of the Adult Self-Report). In addition, to control for associations between different kinds of problems, prediction of Internalizing scores from maternal smoking was tested with scores for Externalizing, Social Problems, and Attention problems partialed out.
Analogously, prediction of Externalizing scores from maternal smoking was tested with scores for Internalizing, Social Problems, and Attention Problems partialed out. It was found that both Internalizing and Externalizing scores were similarly elevated among 5- to 18-year-olds whose mothers smoked during pregnancy. In other words, the apparent effects of maternal smoking did not diminish as the children grew older. The authors concluded that ” . . . even after controlling for the co-occurrence of internalizing and externalizing problems, prenatal exposure to smoking was related to increased levels of both internalizing and externalizing problems from ages 5 to 18 years” (p. 785). Effect sizes were in the small to medium ranges. The authors did not control for postnatal exposure to tobacco smoke, which may be nearly impossible to control for because mothers who smoke during pregnancy are also likely to smoke after their children are born. Nevertheless, the results add to the evidence for the harmful effects of tobacco smoke on a variety of problems over a broad age span.
Reference: Ashford, J., van Lier, P.A.C., Timmermans, M., Cuijpers, P., & Koot, H.M. (2008). Prenatal smoking and Internalizing and Externalizing problems in children studied from childhood to late adolescence. Journal of the American Academy of Child and Adolescent Psychiatry, 47, 779-787.