Use of the anticonvulsant drug valproate during pregnancy may pose a significantly great risk of birth defects than does use of other antiseizure medications.
In the March 22 issue of Neurology, researchers from the North American AED (Antiepileptic Drug) Pregnancy Registry at Massachusetts General Hospital (MGH) report that women taking valproate alone had a fourfold increased risk of having a child with a major malformation, compared with the risk among women taking other anticonvulsants.
"The basic message for women who take valproate is to plan ahead if they want to have children. Discuss the risks with their physician and consider taking alternative drugs," says Lewis Holmes, MD, chief of the Genetics and Teratology Unit at MassGeneral Hospital for Children, director of the registry and senior author of the Neurology paper.
Sold in the U.S. under the brand names Depakote and Depakene, valproate is used to treat seizures, migraines and such psychiatric disorders as bipolar disorder. Earlier studies have suggested a potential risk of birth defects, primarily neural tube defects such as spina bifida, but none had definitively established the level of risk and the types of malformations that most frequently occur.
The North American AED Pregnancy Registry was established in 1996 and has enrolled more than 4,000 women who took anticonvulsant drugs during pregnancy. The current study analyzed information from 149 women who took only valproate while pregnant during the years 1997 to 2003. Of those 149 women, 16 had infants with major birth defects. Three infants had spina bifida, and a wide variety of malformations was seen in the others, including developmental delays.