Antiepileptic medications are among the most commonly prescribed teratogenic drugs among women of childbearing potential. However, determining the exact number of women of childbearing age exposed to antiepileptic medications is difficult. One estimate, based on data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, suggests that from 2005-2007, there were 7 900 000 annual prescriptions for antiepileptic medications among girls and women aged 15 to 44 years, including 926 000 for valproate (12% of all antiepileptic medication prescriptions, irrespective of indication).1 For those treated for epilepsy or seizures, there were 989 000 annual prescriptions, of which 177 000 were for valproate (18% of all prescriptions of antiepileptic medications for epilepsy or seizures).1