Conference Coverage
PHILADELPHIA—Women with epilepsy often have an increased number of seizures when taking a hormonal contraceptive, according to data presented at the 69th Annual Meeting of the American Epilepsy Society. The information was collected from an online survey of 1,144 women with epilepsy.
Women who used hormonal contraception reported having an increased number of seizures while on the contraceptive about 4.5 times more often than did women who used nonhormonal contraception. The risk for an increased number of seizures with hormonal contraception seemed greatest for women treated with valproate.
Until now, “valproate was generally accepted as okay to use” by women also taking a hormonal contraceptive, but the new findings suggest that if a woman of childbearing age with epilepsy needs valproate for seizure control, she would be better off using a nonhormonal form of contraception such as an intrauterine device, said Andrew G. Herzog, MD, Professor of Neurology at Harvard Medical School in Boston and Director of the Neuroendocrine Unit of Beth Israel Deaconess Medical Center in Wellesley, Massachusetts.
Andrew G. Herzog, MD
Dr. Herzog highlighted the need for a form of contraception appropriate for most younger women on valproate because of the drug’s potential teratogenic effects, but he also stressed that the risk of increased seizures does not appear to affect a majority of women. The survey results showed that, overall, 28% of women with epilepsy reported an increased seizure frequency when using a hormonal contraceptive.
“The first goal of a neurologist is to get seizures under control, and you go with the [antiepileptic drugs] that work,” said Dr. Herzog. Once an effective regimen is found, the physician can address other issues, such as adverse effects and the potential for an adverse interaction with a hormonal contraceptive. Valproate can be the antiepileptic drug of choice because it is one of the most effective agents for controlling seizures in patients with primary generalized epilepsy, said Dr. Herzog.
A Large, Community-Based Survey
Internet-based surveys are subject to biases, and the current survey appeared to attract a preponderance of responses from women who were better educated and had higher incomes than the general population. In addition, the researchers collected the data retrospectively. Despite these limitations, the results are notable because they represent the only data set yet reported from a community-based source large enough to allow analysis of the many clinical variables that affect the potential interactions between various contraceptive types, various antiepileptic drug classes, and the diverse number of epilepsy subtypes, said Dr. Herzog. He and his associates are planning a study to collect similar data prospectively, but the results likely would not be available for at least five years, he noted.
The Epilepsy Birth Control Registry enrolled women with epilepsy between ages 18 and 47 who had a history of using at least one form of contraception while on antiepileptic treatment, and the 1,144 women who completed the survey reported a total of 2,712 contraceptive experiences. The survey asked women, “Do you think this method of birth control changed how often you had seizures?” Respondents had the option to reply that their contraceptive method seemed to increase, decrease, or not change their seizure number.
In one of the analyses, Dr. Herzog and his associates compared the responses of women on any form of hormonal contraceptive (eg, combined or progestin pill, hormonal patch, vaginal ring, depot medroxyprogesterone acetate, or implanted hormone) with those of women on any form of nonhormonal contraception (eg, withdrawal, male or female condom, copper or progestin intrauterine device, or tubal ligation).
The results showed that 72% of women on any hormonal contraceptive and 91% of women on any form of nonhormonal contraceptive reported no change in their seizure frequency. The rates of reporting an increased number of seizures were 19% with hormonal contraceptives and 4% with nonhormonal contraceptives, which yielded a relative risk of about 4.5 for an increased number of seizures while on hormonal contraception, compared with nonhormonal contraception, the researchers reported.
Barrier contraception (ie, male or female condoms) had the lowest rate of seizure increase among any of the nonhormonal methods. The risk for greater seizure frequency on hormonal contraceptives of all types was 6.75-fold higher, when compared specifically with barrier contraception.
Hormonal Patch Yielded Greatest Increase in Seizures
In analyses of specific types of hormonal contraceptives, women using a hormonal patch reported a 68% greater incidence of seizure increases, compared with women using combined oral contraceptive pills, which was the hormonal method that produced the fewest episodes of seizure increases. Patients using a progestin-only pill had a 62% higher rate of seizure increases.
