Epilepsy Rx While Pregnant: Does Dose Matter?

Valproate for epilepsy taken in smaller doses during pregnancy can reduce risk for birth defects

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) Researchers have discovered a link between a common epilepsy medication and a specific birth defect in newborn babies. The study sheds light on how women taking epileptic medications during pregnancy can reduce their chance of having a baby with physical deformities.

Epilepsy is a neurological disorder characterized by recurring seizures.

The researchers found that women taking high doses of the epileptic medication valproate (brand name Depakote) had a greater risk of giving birth to a baby with spina bifida than those who took lower doses.  Spina bifida is a birth defect in which a fetus's spine fails to fully develop during early pregnancy.

Over the years, many women with epilepsy feared having a baby since valproate was the only medication that could help prevent their seizures. However, these researchers found that women can reduce their chances of giving birth to a baby with spina bifida by taking smaller doses of valproate during the first three months of pregnancy.

"Discuss your medications with a doctor before getting pregnant."

From this study, Frank Vajda, MD, FRCP, epilepsy specialist and founder of the Australian Pregnancy Register, and colleagues aimed to determine the risk of birth defects among babies born to mothers who were taking valproate while pregnant.

The data was collected between 1999 and 2012 from the Australian Pregnancy Register, an organization dedicated to evaluating the risks of anti-epileptic medications on newborn babies, based at The Royal Melbourne Hospital. The data included more than 1,700 pregnant women with epilepsy.

Of that group of women, 436 took valproate. The average dose for pregnant women taking valproate was 1,367 milligrams per day. Approximately 54 of the 435 pregnant women taking valproate at this dose gave birth to babies with malformed features.

Nearly 80 percent of all instances of spina bifida were linked to valproate.

During the last five years of research, the amount of valproate taken by pregnant women decreased to an average 870 milligrams per day. The researchers found the amount of babies born with spina bifida decreased among pregnant women taking valproate at this dose.

The amount of babies born with other physical deformities other than spina bifida remained the same. 

Dr. Vajda explained the significance of these findings: “We always knew that epilepsy drugs were responsible for the high levels of fetal malformations but we never knew how much dosage played a role until recently,” Dr. Vajda said.

However, Terence O'Brien, MD, epilepsy specialist and co-author of this study, stated that taking smaller amounts of valproate while pregnant did not reduce the risk for other birth defects, such as cleft palates and heart defects. 

This study was published August 2 in the Neurology and was funded by Royal Melbourne Hospital. The authors declared no conflicts of interest.

Review Date: 
August 26, 2013
Last Updated:
August 27, 2013