Older epilepsy drugs such as phenobarbital, phenytoin, valproate and carbamazepine can double or triple the risk of birth defects if a pregnant woman ingests them during the first trimester of pregnancy. But going without them can lead to seizures that also endanger the fetus, so managing a pregnancy in an epileptic woman has generally involved walking a fine line between controlling seizures and reducing developmental problems. But a new generation of epilepsy drugs are thought to reduce the risk of birth defects, and a major new study from Denmark confirms that speculation.
The newer drugs, which include lamotrigine, oxcarbazepine, topiramate, gabapentin and levetiracetam, appear to cause no increase in birth defects, the researchers reported in the Journal of the American Medical Assn. The findings are also good news for pregnant women who take the new drugs for treatment of bipolar disorder, migraine or neuropathic pain syndrome. About half of all prescriptions for the drugs are thought to be for these purposes.
Epidemiologists Ditte Molgaard-Nielson and Anders Hviid of the Statens Serum Institut in Copenhagen used Denmark’s extensive health registries to study all live births in the country from January 1996 through September 2008. Of 837,795 live births, they identified 19,960 children that were diagnosed with a major birth defect — a 2.4% rate. Among the 1,532 women who had taken any of the five new drugs for epilepsy, 49 infants were diagnosed with a major birth defect — a 3.2% rate.
But the team found that many of those women with an affected pregnancy had initially been taking one of the older drugs and had switched to one of the new drugs only after their pregnancy had been confirmed. When the researchers took this into account, the team concluded that there was no increased risk of birth defects associated with the new drugs. The team cautioned, however, that the results did not include enough women who had taken either gabapentin or levetriacetam to reach any conclusions about risk associated with them. Also, the study did not monitor abortions or miscarriages that might have been associated with use of the drugs. Nonetheless, the team said, the results should provide great confidence for expectant mothers who suffer from epilepsy or any of the other disorders.
The study provides new support for the idea that, with careful and informed medication selection, women with epilepsy and neuropsychiatric disorder have the opportunity to have successful pregnancies with antiepileptic drugs that are safe for the developing baby, said Dr. Page Pennell, chair of the professional advisory board of the Epilepsy Foundation. “The progress in this area of research has been tremendous from just a few decades ago when women with these disorders were discouraged from having a family of their own,” she said.