NEW ORLEANS – based on a retrospective study presented at the annual meeting of the American Epilepsy Society.
Data recorded in the 2010-2014 Epilepsy Birth Control Registry indicates a 9.2% infertility rate and a 22.5% impaired fecundity rate among American women with epilepsy. Both rates are higher than the general population infertility rate of 6.0% and the 12.1% rate of impaired fecundity cited by the Centers for Disease Control and Prevention.
However, differences between the study of women with epilepsy and the study of the general population may limit the validity of this comparison, said Devon B. MacEachern, clinical and research coordinator at Neuroendocrine Associates in Wellesley Hills, Mass.
It is likewise uncertain whether use of antiepileptic drugs (AEDs) affects women’s fertility or fecundity.
The Epilepsy Birth Control Registry collected data from an Internet-based survey of 1,144 community-dwelling women with epilepsy aged 18-47 years. Participants provided information about demographics, epilepsy, AEDs, reproduction, and contraception.
The researchers focused on rates of infertility, impaired fecundity, and live birth or unaborted pregnancy among 978 American women, and additionally examined whether these outcomes were related to AED use.
Infertility was defined as the percentage of participants who had unprotected sex but did not become pregnant by 1 year. Impaired fecundity was the percentage of participants who were infertile or did not carry a pregnancy to live birth. The study excluded from the impaired fecundity analysis the 41 respondents whose only outcomes were induced abortions. The 18% of pregnancies that terminated as induced abortions were excluded from the live birth rate analysis.
In all, 373 registry participants had 724 pregnancies and 422 births between 1981 and 2013. The women had an average of 2.15 pregnancies at a mean age of 24.9 years (range, 13-44 years). In addition, 38 women (9.2%) tried to conceive, but were infertile. Of 306 women with a first pregnancy, 222 (72.5%) had a live birth. Among 292 women with two pregnancies, 260 (89.0%) had at least one live birth, and 180 (61.6%) had two live births.
Of the 373 women, 84 (22.5%) with pregnancies had impaired fecundity. The risk of impaired fecundity tended to be higher among women on AED polytherapy than among women on no AED (risk ratio, 1.74).
The ratio of live births to pregnancy (71.0%) was similar among women on no AEDs (71.3%), those on AED monotherapy (71.8%), and those on polytherapy (69.7%). The live birth rate was 67.5% for women taking enzyme-inducing AEDs, 89.1% for women taking glucuronidated AEDs, 72.8% for women taking nonenzyme-inducing AEDs, 63.3% for women taking enzyme-inhibiting AEDs, and 69.7% for women on polytherapy. Lamotrigine use was associated with the highest ratio of live births to pregnancies at 89.1%; valproate use was associated with the lowest ratio of live births to pregnancies at 63.3%.
The investigation was funded by the Epilepsy Foundation and Lundbeck.