Seizures in women of childbearing age commonly show patterns of exacerbation that involve hormones as a factor. Investigators reported the favorable outcome of a multicenter randomized, double-blinded, placebo-controlled phase III clinical trial of progesterone therapy in reducing these perimenstrually exacerbated (catamenial) seizures. Results of the NIH-sponsored study are being presented during the American Epilepsy Society's 65th annual meeting here at the Baltimore Convention Center. (Abstract 3.191)

Progesterone is a naturally occurring steroid known to dampen neuronal excitability and seizures. The purpose of the clinical trial was to compare progesterone versus placebo in lessening seizures in women with partial epilepsy.

"We found that progesterone can provide a clinically important benefit for a substantial portion of women with catamenial seizures," says lead investigator Andrew G. Herzog, M.D., M.Sc., of Harvard University. "And, the level of perimenstrual seizure exacerbation is a significant predictor of women most likely to benefit from this hormonal therapy."

The proportion of responders to progesterone therapy increased relative to the increased level of perimenstrual seizure exacerbation; whereas, no significant difference in responder rate was observed in women with seizures that did not show substantial perimenstrual exacerbation, i.e threefold or greater increase in average daily seizure frequency.

The clinical trials were conducted at the Beth Israel Deaconess Medical Center and Brigham and Women's Hospital Boston, Thomas Jefferson Hospital, Philadelphia, University of Southern California's Keck School of Medicine, and the University of Maryland, Department of Neurology.