During pregnancy, use of the antiepileptic drug valproic acid has been associated with worse outcomes–including fetal loss, impaired growth, major congenital malformations, increased risk of developmental problems, and autism–compared with all other antiepileptic drugs. A new Epilepsia study has found that when human placentas are exposed to valproic acid, they express lower levels of transporters for compounds essential for fetal growth and development (such as glucose and folic acid).
The findings suggest that valproic acid's effects on the placenta may be involved in the adverse developmental outcomes seen in fetuses exposed to the drug.
"Despite the risk, there are cases in which valproic acid may be the only drug that can control seizures in pregnant women," said senior author Dr. Sara Eyal, of the Hebrew University of Jerusalem, in Israel. "We continue our studies to understand why some fetuses are adversely affected by valproic acid whereas others are not."