Findings from a UK study confirm previous reports linking smoking during pregnancy with an increased risk of cleft lip. In contrast with some earlier study findings, the researchers also found that the risk of cleft palate was also heightened.

The study, which is reported in the Cleft Palate-Craniofacial Journal, involved a comparison between 190 children with orofacial clefts and 248 children without these birth defects.

Dr. J. Little, from the University of Aberdeen, and colleagues found that 80 mothers of infants with clefts and 59 mothers in the control group smoked during the first trimester.

The investigators calculate that maternal smoking during the first trimester of pregnancy increased the odds of cleft lip with or without cleft palate by 1.9-fold and the risk of cleft palate by 2.3-fold.

For both types of cleft, the risk was directly related to the amount smoked, the researchers point out.

Although there was evidence that passive smoking also raised the risk of orofacial clefts, the study did not have sufficient statistical power to confirm or refute this association.

In light of these findings, the authors comment, “It may be useful to incorporate information on the effects of maternal smoking on oral clefts into public health campaigns on the consequences of maternal smoking.”

Cleft Palate Craniofacial Journal, July 2004.