LOS ANGELES ― Many people of childbearing potential may not realize that their antiseizure medications (ASM) can raise the risk of birth defects or make their birth control less effective, suggests a study presented at the American Epilepsy Society Annual Meeting. Additionally, some birth control methods can make ASMs less effective.
People of childbearing potential were surveyed regarding what ASMs they take, if they were either pregnant or planning to become pregnant, or what birth control method they used. When asked about the safety of their ASMs for pregnancy or whether their ASMs and birth control interfered with one another (drug-drug interaction), nearly two-thirds answered at least one question wrong. Only about a third were receiving care that aligned with their reproductive goals.
ASMs that increase the risk of birth defects include valproic acid, topiramate, carbamazepine, phenobarbital and phenytoin. However, no ASM is as dangerous ― for the fetus or the person who is carrying it ― as uncontrolled seizures, the researchers note. People who want to become pregnant should be prescribed ASMs that are less risky but only if they effectively control their seizures.
ASMs that can make hormonal contraceptives such as pills, patches and rings less effective include carbamazepine, phenytoin, phenobarbital, higher doses of topiramate and oxcarbazepine. Hormonal contraceptives can make ASMs such as lamotrigine, valproate, zonisamide and rufinamide less effective. Those who don’t want to become pregnant should take an appropriate ASM that doesn’t make their birth control method less effective and vice versa.
“Neurology and reproductive health care providers should collaborate to provide the safest and most effective care for their patients of reproductive age who are taking anti-seizure medications,” said Sarah Betstadt, MD, MPH, senior author of the study and associate professor of obstetrics and gynecology at the University of Rochester Medical Center, New York. “This collaboration can help patients navigate their reproductive choices while minimizing drug-drug interactions that may reduce the effectiveness of seizure medications and/or birth control methods.”
For the study, 107 people aged 18-49 who were taking ASMs were surveyed about their reproductive intentions: six said they were pregnant or planning to become pregnant and 69 said they were using a barrier, hormonal or implant form of contraception, which could interfere with their ASM or vice versa. The remainder were either abstaining, using other forms of contraception or not using any contraception. Only 36% were receiving care in alignment with their reproductive goals, eg. they were taking folic acid if they were pregnant or planning to become pregnant or using a highly effective contraceptive if not.
Based on the answers to the survey, the researchers determined many people did not have adequate knowledge of the potential risks of their ASMs.
- 67.3% answered at least one question incorrectly regarding whether the ASM they were taking increased the risk of birth defects or their ASM reduced the effectiveness of their contraceptive or vice versa
- 56.1% of those who planned to become pregnant answered at least one question incorrectly regarding the birth defect risk of their ASMs
- 36.2% of those using a barrier, hormonal or implant contraceptive answered at least one question incorrectly regarding whether their ASM decreased birth control effectiveness
- 36.2% of those using a barrier, hormonal or implant contraceptive answered at least one question incorrectly regarding their birth control’s effect on their ASM’s effectiveness
- 72.9% said they did not want more education about their ASM regarding the risks of birth defects or its interaction with their birth control
- 29.2% of those who answered at least one question incorrectly said they wanted more education
“Survey participants may not have known that their answers were wrong and so did not feel they needed more information,” said Dr. Betstadt. “Many neurologists do not learn about birth control in their training, even though they know that ASMs may have some risks in pregnancy. We hope this study raises awareness for patients and encourages health care providers from neurology and reproductive health care to work together to ensure the best care for these patients.”
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