A recent study published in Epilepsia, a journal of the International League Against Epilepsy (ILAE), determined that women with secondarily generalized tonic-clonic seizures had a higher number of seizures during anovulatory cycles (when an egg is not released) than during ovulatory cycles (when an egg is released). According to the study, reproductive hormones could affect the occurrence of generalized tonic-clonic seizures.
There has been medical evidence showing that estradiol and progesterone, two sex hormones, have neuroactive properties that can affect seizures. Hormone levels in the blood differ depending on whether or not an egg is released during menstrual cycles; anovulatory cycles have higher estradiol-progesterone ratio levels during the second half of the menstrual cycle compared to ovulatory cycles. Previous studies, including ones by Andrew Herzog, M.D., M.Sc. of Beth Israel Deaconess Medical Center in Boston, MA and colleagues, have determined that anovulatory cycles occur more commonly in women with epilepsy than in the general population.
To expand on their earlier research, Dr. Herzog and colleagues, including Page B. Pennell, M.D. the chair of the Epilepsy Foundation’s Professional Advisory Board, used data collected from the Progesterone Trial Study—an investigation of progesterone therapy for difficult to control focal onset seizures. Ninety-two of the 281 women who completed a 3-month baseline phase had both anovulatory and ovulatory cycles. Researchers found that in these women, the average daily seizure frequency for secondarily generalized tonic clonic seizures was 30% greater during anovulatory cycles than during ovulatory cycles. Average daily seizure frequency did not differ significantly for the less severe types of seizures (complex partial, simple partial, or combining all types of seizures).
"Our results showed that generalized tonic-clonic seizure frequency during anovulatory cycles correlate with proportional increases in estradiol-progesterone level ratios, suggesting sex hormones contribute to seizure incidence," concluded Dr. Herzog. "Efficacy results from the phase 3 clinical trial of a progesterone supplement that generated the data for the current study are forthcoming, and may provide a much needed treatment option to control seizures in women with epilepsy."