Babies born to mothers exposed to antiepileptic drugs (AEDs) are at increased risk for major congenital malformations, cognitive impairment and fetal death. For the millions of women with epilepsy, maintaining the safest drug that will successfully prevent seizures during pregnancy remains a primary consideration. The recent development of collaborative international registries to examine the differential and dose-dependent effects of the expanding number of old and new AEDs, have shed light upon potential differences during pregnancy. Valproic acid appears to be associated with the highest risk of overall, as well as AED-specific, birth defects, becoming more evident as doses exceed 1000 mg/day. Lamotrigine may be less teratogenic to humans than other AEDs, although orofacial clefts have recently been reported. The effects of polytherapy appear to carry greater risks compared with monotherapy. Limited data exist for many of the newer AEDs. Furthermore, AED effects may persist during postnatal development. Although no class 1 outcome data are available, prepregnancy counseling to optimize patient-specific treatment is recommended for women of childbearing potential with epilepsy.