Women with Epilepsy: A Handbook of Health and Treatment Issues (Chapter 12)

Epilepsy and the menstrual cycle (Excerpt)

Patricia O. Shafer and Andrew G. Herzog

What changes in menstrual cycles occur in women with epilepsy?

One-third to one-half of women with temporal lobe epilepsy report menstrual cycle problems. These include going several months without menstruation (amenorrhea), having menstrual cycles longer than 35 days (oligomenorrhea), or unusually long (greater than 32 days) or short (less than 26 days) times between menstrual periods. Ovulation does not occur (anovulatory cycles) and, therefore, progesterone is not secreted during the second half of the cycle (inadequate luteal phase cycle) in approximately 35% among women in the general population (Cummings et al., 1995). Women with the above-listed menstrual disorders are more likely to have anovulatory and inadequate luteal phase cycles. These cycles usually result from abnormal hormone secretion and are associated with increased seizure frequency.

Some of these menstrual cycle problems are the result of distinct reproductive endocrine disorders, which involve the production of abnormal quantities of reproductive hormones. Polycystic ovarian syndrome (PCOS) and hypothalamic amenorrhea are examples of reproductive endocrine disorders that are thought to occur more frequently in women with partial epilepsy. Exactly how frequently these problems occur is not yet known; however, Herzog et al. suggest that PCOS (which involves the occurrence of menstrual disorders, excess hair growth, and small cysts in the ovaries associated with elevated serum levels of androgens – masculizing hormones) occurs in about 20% of women with temporal lobe epilepsy, as compared to 5% of the general population. Hypothalamic amenorrhea (characterized by menstrual disorders, including loss of menses, associated with low pituitary FSH and LH as well as low estrogen levels) occurs in about 12% of women with temporal lobe epilepsy, as compared to 1.5% of the general population. Both of these epilepsy-related conditions are associated with inadequate luteal phase cycles, which can result in infertility and increased seizure occurrence.

Some researchers believe that certain seizure medications may contribute to menstrual cycle problems. It is not unusual for women who change medications to experience a change in their menstrual periods. This type of change is often temporary, and once their body gets used to the new medicine, the menstrual periods become more regular. Other women notice changes that persist for a period of time and can be bothersome. We know that some medications taken for mood or thought disorders, such as depression, may affect menstrual cycles. Sodium valproate, used for both seizures and mood disorders, has been associated with long periods of time without menstruation and possibly with a greater chance of developing PCOS. It is not definitely known whether the medication makes a woman more likely to have this condition, or if the underlying seizure disorder is the cause. Other medications have not been studied exclusively for their effect on menstruation in women with epilepsy.

-- Excerpted from "Women with Epilepsy: A Handbook for Health and Treatment Issues" edited by Martha J. Morrell, MD and Kerry L. Flynn, M.A. Published by Cambridge University Press, 2003. It is available for purchase in our marketplace.