Cigarette smoking has, fortunately, declined in recent years, but roughly 11% to 12% of pregnant women continue to smoke.1 Women who smoke are more likely to experience infertility, premature rupture of the membranes, placental abruption, and placenta previa during pregnancy than women who do not smoke. Infants born to mothers who smoke are at greater risk of stillbirth, preterm birth, low birth weight, and sudden infant death syndrome.

Another harmful effect has been added to the list: congenital heart defects. A population-based, case-control study suggests that women who smoke in the periconceptional period (from 1 month before pregnancy to the end of the first trimester) are more likely to give birth to infants with septal heart defects than control mothers, and the risk increases with the number of cigarettes smoked.2 Women who smoke 25 or more cigarettes per day are more likely to deliver infants with right-sided obstructive heart defects, such as pulmonary valve stenosis, than nonsmoking mothers.2

Congenital heart defects are not the only birth defects found to be associated with maternal smoking. Studies have confirmed an increased incidence in orofacial clefts, omphalocele, gastroschisis, clubfoot, hydrocephaly, microcephaly, and polydactyly/syndactyly/adactyly in the offspring of smoking mothers.3

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