Nearly 1 in 2 women of childbearing age who have epilepsy report an increase in seizures around the time of their monthly menstrual period. Seizures occurring predominantly around the time of menstruation are referred to as catamenial epilepsy. Studies reveal that the premenstrual and ovulatory phases are associated with the highest seizure frequencies. The premenstrual period consists of a few days before the period begins, and the ovulatory phase starts mid-cycle.

The hormonal changes associated with the menstrual cycle are the most likely cause of changes in seizure frequency. The brain contains numerous nerve cells that are directly affected by estrogen and progesterone, the main sex hormones in women. Studies in animals have shown that high doses of estrogen can cause or worsen seizures, whereas high doses of progesterone can act like an antiepileptic drug.

If you are a woman of childbearing potential and it appears that your seizures are associated with your menstrual cycle, your doctor might recommend further tests, such as blood hormone levels and a pelvic ultrasound. In addition, he or she might slightly increase the dosage of your antiepileptic drugs before the time of increased seizure frequency, assuming that you have regular cycles. Other strategies could include taking an additional antiepileptic drug such as lorazepam for several days around the most vulnerable time of the menstrual cycle, or using hormones such as progesterone, depending on the results of blood tests. Your doctor might recommend that you consult with an endocrinologist or gynecologist.

Tips for managing hormone-sensitive seizures

• Make sure you track your menstrual period on your seizure calendars. The first day of your menstrual cycle would be counted as day 1. Then keep track of the menstrual cycle day on each calendar day. When your menstrual period begins again, your menstrual cycle day would be day 1 again.
• Note when your seizures occur. When you report them to your doctor, let him or her know what menstrual cycle day they occurred on. For example, in some women, seizures occur only during the last week before your menses begins. Others may notice that they occur in the middle of the cycle as well as right before their menses.
• Record on your Seizure Plan any hormonal treatment or other 'as needed' medicines that may be used during your menses or your high-risk time. This will serve as a great reminder of when to take the medicines.
• Record the use of hormonal treatment or other 'as needed' medicines on your seizure diary. This will help you know if the treatment helped or not.

Topic Editor: Steven C. Schachter, MD and Patricia O. Shafer, RN, MN.
Last Reviewed: 9/30/08