Although several epidemiological studies suggest that smoking cigarettes while pregnant is a risk factor for cleft lip/palate, most of them are small-scale efforts that have not clearly established an association. The present authors used the US Natality database from 1996 and a case-control design to analyze approximately 3,891,000 live births. The 2207 infants with cleft/lip palate were compared with twice this number of control infants lacking congenital defects.Maternal factors associated with anomalies included being nonblack and having less than a high-school education, diabetes, and pregnancy-associated hypertension. Affected infants were more likely to be males. The case and control subjects did not differ in terms of when prenatal care began. Multivariate logistic regression analysis adjusting for both infant and maternal variables yielded a significant association between any degree of cigarette smoking during pregnancy and an increased risk of cleft/lip palate. The adjusted odds ratio was 1.34. Maternal diabetes and pregnancy-related hypertension also were risk factors. Black mothers, older women, and those with more than a high school education were less likely to have an affected infant. A birth weight exceeding 4000 gm seemed to be protective, whereas a weight less than 2500 gm was a risk factor. Some dose-response relationship was evident; the odds ratio was 1.69 when mothers smoked 1 pack or more per day. The relationship persisted when other control infants with anomalies not found to be associated with smoking were analyzed.Maternal cigarette smoking during pregnancy is significantly associated with cleft lip/palate deformity in the newborn infant, and a dose-response effect contributes to the causative status of this association. The risk level is modest, but the many women in the United States who smoke while pregnant means that thousands of children potentially could be affected. Obviously expectant mothers who smoke should be warned of this risk.Plast Reconstr Surg 2000;105colon;485ndash;491
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