This study will measure and compare hormone levels in women with catamenial epilepsy (epilepsy in which seizures are more frequent during menstrual periods), women with seizures not related to their menstrual cycle, and normal control subjects. It will determine whether there are differences among the three groups in their hormone levels or in how fast the levels change. It will also examine what relationship, if any, exists between hormone changes and seizures in women with catamenial epilepsy. The hormones under study include the gonadal hormones estrone, estradiol and progesterone, and the neuroactive steroids allopregnanolone, pregnenolone, and dehydroepiandrosterone.