Epilepsy Drug in Pregnancy Raises Spina Bifida Risk
But Experts Say Pregnant Women With Epilepsy Need to Weigh Risks and Benefits of Carbamazepine
Dec. 2, 2010 -- Babies born to women who take the antiseizure drug carbamazepine have a more than twofold increased risk for the birth defect spina bifida, a study shows.
But researchers say the drug still has less risk of birth defects overall than the epilepsy drugs valproic acid.
Researchers reviewed birth outcomes among almost 4 million babies born in Europe between 1995 and 2005, including almost 100,000 who had major birth defects and 2,680 whose mothers took carbamazepine during the first three months of their pregnancies.
They concluded that spina bifida was the only major birth defect associated with exposure to carbamazepine, known by the brand names Carbatrol, Epitol, Equetrol, and Tegretol.
Spina bifida is a neural tube defect that occurs when the fetus’s spine fails to close properly during the early weeks of pregnancy.
The study was published online today in the journal BMJ Online First.
Risks of Valproic Acid
Last June, the researchers reported a sixfold increase in spina bifida risk in babies born to women who took the epilepsy drug valproic acid, sold as Depacon, Depakene, Depakote, and Stavzor.
Valproic acid was linked to a higher risk for several birth defects, including cleft palate, extra fingers and toes, and hypospadia -- a condition in which a male’s urinary opening develops in the wrong part of the penis or in the scrotum.
The new findings bolster recent guidelines from the American Academy of Neurology recommending that women avoid valproic acid, if possible, during pregnancy.
Since switching antiseizure drugs during or just before pregnancy is not recommended, many neurologists try to avoid prescribing valproic acid to their female patients during their childbearing years.
But this is not always possible, says study researcher Lolkje de Jong-van den Berg, who is a professor in pharmacoepidemiology at the University of Groningen in the Netherlands.
“If carbamazepine is effective for controlling seizures it is clearly the best choice,” she tells WebMD. “But this is not always the case. In some cases, valproic acid may be the only effective option.”
She points out that while the relative risk for birth defects is elevated, the overall risk in children born to women who take antiseizure drugs -- including valproic acid -- is still quite low.