Design. Subjects will undergo baseline monitoring of seizures and menses for two months prior to entry. Upon enrollment into the study, blood (10 ml) will be drawn for determinations of estradiol, estrone, progesterone, allopregnanolone, dehydroepiandrosterone (DHEA) and pregnenolone in all study populations once daily at 08:30 hr on menstrual cycle days, 10, 14, 17, 19 and 21; and three times daily at 08:30, 13:30 and 18:00 starting 5 days before expected menses and continuing for a total of 8 days as well as on menstrual cycle day 6. During 8 days starting 5 days before expected menses interictal spike activity and seizures will also be monitored continuously with EEG. Comparisons of the rates of change of hormone levels and spike and seizure frequency will be made using the time derivatives of fluctuations in hormone levels or hormone level ratios. Comparisons of time series data will be made using nonlinear regression with an arbitrary (cubic spine) model.