Combined effects of cigarette smoking and alcohol consumption on perinatal outcome

An increase in various congenital abnormalities associated with cigarette smoking and the use of alcohol during pregnancy has been reported in many studies. These exposures also increase the risk of pregnancy complications such as abruptio placentae, unexplained stillbirth, preterm labor and intrauterine growth restriction. However, very few studies have addressed the combined effect of smoking and drinking on pregnancy outcomes.

In this review, the adverse effects of smoking or drinking on pregnancy were obtained from publications in which both substances were addressed in the same study population. A special effort was made to find studies in which the combined effect of these substances was investigated.

Preterm labor occurred more frequently in women who drank and smoked during pregnancy. This increased odds ratio was more than the sum of the effects of either smoking or drinking, indicating that the use of both substances by the same woman has a synergistic effect that increases the risk of preterm labor. This synergistic effect was also found for low birth weight and growth restriction.

As most of the women who drink during pregnancy also smoke cigarettes, attention should be given to the prevention or reduced use of both substances during pregnancy.