Patterns of seizure occurrence in catamenial epilepsy.

The pattern of seizure occurrence was analysed over 44 menstrual cycles in 12 epileptic women who considered they had menstrually related seizures. Two peaks in the daily seizure rate were apparent. A significant increase in seizures occurred during the days of menstrual flow and the two days preceding it, with a second peak in the four days at midcycle. The lowest seizure rate was in the late phase of the menstrual cycle. Daily salivary progesterone levels were assayed in 11 women, and 12 ovulatory and eight anovulatory cycles were identified on this basis. No increase in seizures occurred at midcycle if ovulation did not occur, but the perimenstrual increase took place irrespective of ovulatory status.