Antiepileptic drug therapy in pregnancy II: fetal and neonatal exposure.

The issue of how much an antiepileptic drug (AED) crosses the placenta and relative safety of lactation in mothers receiving AEDs are common clinical questions. Educating potential mothers with epilepsy regarding available information is warranted so that informed decisions and any needed neonatal monitoring is performed. Unfortunately, there is still limited data regarding the degree in which anticonvulsants cross the placenta and penetrate into breast milk. There is a greater appreciation of the factors that influence AED passive transfer across the placenta and into breast milk, as well as factors that ultimately influence neonatal AED distribution. In general, women with epilepsy can have healthy babies even with significant placental exposure and can breast-feed their babies safely with some cautions. Phenobarbital and primidone should be avoided in parents wishing to breast-feed. For the AEDs ethosuximide, levetiracetam, lamotrigine, topiramate, and zonisamide, there is a potential for significant breast milk concentrations; however, there are no firm guidelines on whether lactation is safe. In all cases, parents should be counseled to monitor their child for side effects and the need for routine monitoring.