Secondhand smoke puts pregnant women at increased risk for having a baby with a cleft lip, says a review of published research that appears in the journal PLoS One.
Authors from Canada, Egypt and the United Kingdom reviewed 14 studies on the topic. After adjusting for other factors that could affect risk, the authors found that women exposed to secondhand smoke had a 50% greater risk of having a baby with cleft lip, or cleft lip and palate, compared with women who were not exposed to secondhand smoke.
Past research has shown an increased risk for cleft lip and palate in the babies of pregnant women who smoked. The risk found in those studies is about the same as the risk this study found for secondhand smoke.
A previous research review found that women exposed to secondhand smoke had a 23% greater risk of stillbirth and a 13% greater risk of having a baby with a physical malformation.