Epilepsy, antiepileptic drugs, and the risk of spontaneous abortion.

The possible effect of in utero antiepileptic drug (AED) exposure on the incidence of spontaneous abortion was evaluated among pregnancies of women with epilepsy and the wives of men with epilepsy. The proportion of pregnancy outcomes terminating in spontaneous abortion, the gestational age-specific rates of spontaneous abortion, and the cumulative risks of spontaneous abortion were determined. The gestational age-adjusted rate ratio for spontaneous abortion of 0.80 (95% confidence interval 0.45-1.40) was not increased for the pregnancies of women with epilepsy compared with those of the wives of men with epilepsy. Among women with epilepsy the rate ratio for in utero exposure to AED exposure was 1.14 (0.52-1.47) and was consistent with no effect of AED on fetal loss. The cumulative risk of spontaneous abortion of 18% for AED exposed pregnancies was also similar to risks reported in nonepilepsy populations. Thus, neither epilepsy nor in utero AED exposure was found to be associated with recognized fetal loss.