Fetal valproate syndrome (FVS) is caused by exposure to the anticonvulsant drug (AED) valproic acid (trade name Depakene, Depakote, among others). Valproic acid is a pre¬ natal teratogen, and a small percentage of women who take the drug in the first trimester of pregnancy will have off-spring with one or more signs of the syndrome. The effects, particularly craniofacial, of prenatal exposure to valproate are so similar to those of several other AEDs, including carbamazepine, hydantoin, mysoline, and phenobarbital, as to have led to the general descriptive term fetal antiepileptic drug syndrome.