WASHINGTON, DC—Approximately half of women with epilepsy of reproductive age take folic acid supplements, according to an analysis presented at the 67th Annual Meeting of the American Epilepsy Society. The figure is cause for concern because enzyme-inducing antiepileptic drugs (AEDs) are associated with folic acid deficiency, which increases the risks of fetal loss and of neural tube defects among offspring, said Andrew G. Herzog, MD. Furthermore, data indicate that women with epilepsy have a higher risk of unintended pregnancy than women in the general population.
Physicians have known about the risks associated with folic acid deficiency and the association between AEDs and folic acid deficiency for approximately 30 years, but folic acid supplementation has not increased during that time. “It may be time for a campaign by epilepsy organizations, pharmaceutical companies, and health care providers to encourage use of folic acid by women with epilepsy,” said Dr. Herzog, Professor of Neurology at Harvard Medical School in Boston. The results of such a campaign should be monitored, he added.
The Epilepsy Birth Control Registry
The results come from an interim analysis of data from the Epilepsy Birth Control Registry. The web-based survey gathers information about demographics, epilepsy type, AED use, contraceptive use, reproductive status, and folic acid supplementation from women with epilepsy of reproductive age. Dr. Herzog and colleagues based their interim analysis on data from the first 650 women who completed the survey, 414 of whom were considered to be at risk of pregnancy.
The outcomes of the study were the proportions of women who used folic acid overall, and stratified by demographics, seizure type, AEDs, risk of pregnancy, contraceptive type, and whether respondents had visited a health care provider during the year before responding to the survey. Statistical analysis determined the relative frequency of folic acid use, and the researchers identified predictors of folic acid use through stepwise binary logistic regression.
Supplementation Was Lowest Among Women Most at Risk
Among all women in the sample, the rate of folic acid use was 42.9%. The rate of folic acid use was 46.3% among women at risk of pregnancy and 46.1% among women at risk of pregnancy who took contraceptives. The only group for which the rate of folic acid use was more than 50% was women with epilepsy at risk of pregnancy who did not take contraception and were actively seeking pregnancy. The population most at risk—women with epilepsy at risk of pregnancy who took no contraception and were not seeking pregnancy—had the lowest reported rate of folic acid use (25%). Women with epilepsy at risk of pregnancy who took AEDs had a higher rate of folic acid use (47%) than women with epilepsy who were not taking an AED (26.7%).
Education level and AED category emerged as the two significant predictors of folic acid use. Women with a college degree were 25% more likely to use folic acid than women without a degree. The researchers found no significant difference in the relative frequency of folic acid use between women with epilepsy who did (44.4%) and those who did not (39.6%) see a health care provider during the year before the survey.
Women with epilepsy who took valproate used folic acid significantly less often than women with epilepsy who took enzyme-inducing drugs, glucuronidated drugs, or nonenzyme-inducing drugs. This finding was surprising because valproate, a folic acid antagonist, is associated with the highest frequency of neural tube defects of all AEDs, said Dr. Herzog. A potential explanation for this result is that significantly fewer women receiving valproate in the sample had college degrees (29.5%) than women receiving other AEDs (50.3%). It remains unclear whether AED type is a factor in the rate of folic acid use, or whether the finding results from the characteristics of the sample, concluded Dr. Herzog.
—Erik Greb