Associations between particular types of fetal malformation and antiepileptic drug exposure in utero

Objective - To study associations between patterns of fetal malformation and individual antiepileptic drugs taken during pregnancy. Methods - Multiple variable logistic regression and other statistical analyses of data relating to 1733 fetuses from 1703 pregnancies (147 of which were not exposed to antiepileptic drugs during pregnancy). Results - There were statistically significant (P<0.05) associations between (i) valproate exposure and spina bifida, malformations of the heart and great vessels, digits, skull bones, and brain, but not hypospadias, cleft palate/lip and mouth abnormalities, (ii) topiramate exposure and hypospadias and brain maldevelopments, and (iii) carbamazepine (CBZ) exposure and renal tract abnormalities. Conclusions -The valproate findings are mostly in keeping with the published literature, but the topiramate finding regarding hypospadias and the association between CBZ exposure and various renal tract abnormalities raise questions of organ specific teratogenesis. More extensive data are desirable, particularly in relation to topiramate, which is being used increasingly as a migraine prophylactic in women of childbearing potential.