The vast majority of women with epilepsy are able to get pregnant, with relatively few issues, new research shows.

“There has been the notion and some evidence in the past that fertility is reduced in women with epilepsy compared with the general population, but what these findings suggest is that 90% of women with epilepsy can get pregnant,” study investigator Andrew G. Herzog, MD, professor and director, Neurology, and Neuroendocrine Unit, Beth Israel Deaconess Medical Center, Wellesley, Massachusetts, told Medscape Medical News

The study was presented here at the American Epilepsy Society (AES) 72nd Annual Meeting 2018.

Registry Data

The researchers used retrospective data from a web-based epilepsy birth control registry. Any woman with epilepsy can complete the online survey and get educational materials on safe and effective contraception.

From this registry, researchers had reproductive data on 978 women aged 18-47 years with epilepsy. This included demographic, epilepsy, anti-epilepsy drug (AED), contraceptive, and reproductive data.

The investigators analyzed three outcomes:

• Infertility rate: The percentage of women who had unprotected sex but did not achieve pregnancy after 1 year.
• Impaired fecundity rate: The percentage of women who were infertile or did not carry a pregnancy to live birth, excluding abortions.
• Live birth rate: The percentage of pregnancies that resulted in live births, excluding abortions.

A total of 411 women attempted to become pregnant. Of this group, 373 had 724 pregnancies resulting in 445 live births.

The mean age at pregnancy was 24.9 years, but women who became pregnant ranged in age from 14 to 44 years.

Some 72.6% of the women had a live birth at first pregnancy and 89.0% had at least one live birth in their first two pregnancies.

Of the 411 women, 38 tried but were unable to become pregnant at the end of 1 year, for an infertility rate of 9.2% (95% CI, 6.7 – 12.4). In contrast, the infertility rate among the general population is 6.4%, as estimated by the Centers for Disease Control and Prevention (CDC).

About 20.7% of the women had impaired fecundity, which included the 38 individuals who were infertile and 46 pregnancies that did not result in a live birth.

Impact of AEDs Unclear

Investigators also examined the potential impact of AEDs on fertility. They compared no AED to monotherapy and polytherapy, and no AED to specific classes of AED, including enzyme-inducing, non-enzyme-inducing, enzyme inhibitory, and glucuronidated drugs.

They found that for women on any AED, the rate of infertility was twice that of those not taking an AED (10.3% vs 4.2%), although the sample sizes in this interim analysis were too small to be statistically significant, said Herzog.

Devon MacEachern, BS, who presented the data at a Platform Session during the meeting, said the study would need more than double the participants in the any AED category for the study to be adequately powered to make meaningful conclusions about the potential impact of AEDs on fertility.

The impaired fecundity rate was also almost two times greater for women on any AED than for those not taking an AED (22.2% vs 13.9%; relative risk [RR], 1.79; 95% CI, 0.94 – 3.11; P = .08).

Comparisons of various individual monotherapies to polytherapy were not significant.

In addition, the live birth rate was similar for women on any AED (73.9%) compared with those not taking an AED (79.1%).

However, when investigators examined the impact of specific drugs on fertility, the analysis showed that women on lamotrigine had a significantly higher live birth rate than their counterparts on valproate (89.1% vs 63.3%; RR, 1.41; 95% CI, 1.05 – 1.88; P = .02).

Physicians have numerous issues to discuss with their female patients with epilepsy during office visits. These include seizure management, safety and risks of individual AEDs, as well as contraception, which is “often not adequately addressed,” said Herzog.

A limitation of the study is that the information was self-reported. Also, the women who completed the registry surveys were younger and better educated than the general population, and minority women were under-represented.

Following MacEachern’s presentation, one delegate asked whether the fertility of the women’s partners may have contributed to fertility failure rates.

The “downfall” of this study, and of a CDC general population study, is that they don’t determine whether the male or female contributed to the infertility, she said.

Good News for Patients

Commenting on the study for Medscape Medical News, session co-chair, Kelly Knupp, MD, Pediatric Neurology and Epilepsy Program, Children’s Hospital Colorado, said the results are “good news” for patients.

“The fear of many teenage girls with epilepsy is that they can’t have babies.”

The higher infertility rate among women with epilepsy uncovered by the study is something “we worry about in terms of what that means in a bigger population and something [physicians] have to be cognizant of.”

However, as information in the database is self-reported, “we have to be a little cautious because it doesn’t represent the entire population,” she said.