Objective: To evaluate the possible association between all kinds of drug treatments during pregnancy and isolated cleft lip with or without cleft palate (CL/P) and posterior cleft palate (PCP) in the offspring.
Setting: The dataset of the large population-based Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996, was evaluated.
Participants: One thousand three hundred seventy-four cases with isolated CL/P and 601 with PCP, plus 38,151 population controls (without birth defects) and 20,868 malformed controls with other defects.
Intervention: In this observation case-control study the data collection was based on prospective medical records particularly prenatal logbook, retrospective maternal data via a self-reported questionnaire, and home visits of nonresponding mothers.
Main outcome measures: Isolated CL/P and PCP associated with drug treatments during pregnancy.
Results: An increased risk for isolated CL/P was found in cases born to mothers treated with amoxicillin, phenytoin, oxprenolol, and thiethylperazine during the second and third month of pregnancy, i.e., the critical period of isolated CL/P. Risk of isolated PCP was increased in mothers with oxytetracycline and carbamazepine treatment during the third and fourth month of pregnancy, i.e., the critical period of PCP.
Conclusions: This study confirmed the orofacial cleft (OFC) inducing effect of phenytoin, carbamazepine, oxytetracycline, and thiethylperazine and suggested a possible association between OFCs and oxprenolol and amoxicillin. However, drugs may have only a limited role in the origin of isolated OFCs.