Topamax May Raise Risk of Birth Defects
Small Study Shows Increase in Birth Defects When Epilepsy/Migraine Drug Is Used During Pregnancy
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Of the 178 live births that occurred, three babies whose mothers took Topamax alone and 13 whose mothers took Topamax along with other anti-epilepsy drugs had major birth defects.
Four of the babies had cleft palates or cleft lips, which was 11 times higher than would be expected among women not taking epilepsy medication. Four male babies had genital birth defects, with two of these classified as major birth defects.
The birth defect rate was highest among women who took Topamax in combination with the epilepsy drug valproate, which has been linked to birth defects in numerous studies and epilepsy databases.
NYU professor of neurology Jacqueline A. French, MD, tells WebMD that the birth defect rate among women taking Topamax alone was within the realm of what has been seen with epilepsy drugs considered safer than valproate. French is a spokeswoman for the American Academy of Neurology.
"It was somewhat surprising that the rate was so high when Topamax was used with valproate," she says. "But the risk associated with valproate is well known, and this drug is already avoided whenever possible during pregnancy."
French tells WebMD that the study was too small to accurately assess the risk to babies born to mothers who take Topamax alone.
Kara Russell, a spokeswoman for Topamax manufacturer Ortho McNeill Neurologics, expressed similar concerns. "The sample sizes in this study were small, so more work needs to be done to really understand the results," she tells WebMD.
"We continue to support studies to provide clarity on the use of our drug in this population," she adds. "But it is really hard to reach a conclusion based on the small sample sizes in this study."
Three major databases currently track birth defects among babies born to women taking epilepsy drugs, but only one has so far provided information on Topamax, French says.
"We should know more soon when the other databases report on this drug," she says.
Like Shinnar, French emphasizes that for pregnant women with epilepsy, uncontrolled seizures have proven to be a much greater risk to the fetus than any epilepsy drug, including valproate.