Newswise — In women with epilepsy, having a longer or shorter menstrual cycle reduces ovulation, and lack of ovulation increases seizure frequency, according to research that will be presented at the American Academy of Neurology 58th Annual Meeting in San Diego, Calif., April 1 " 8, 2006.
"Ovulation rates are lower among women with epilepsy than in the general population," said the study's lead author Andrew Herzog, MD, M.Sc, FAAN, of the Harvard Neuroendocrine Unit at Beth Israel Deaconess Medical Center in Boston, Mass. "It has been suggested that these low ovulation rates may be due in part to menstrual cycles that are longer or shorter than normal, and that lack of ovulation may in turn correlate with increased frequency of seizures, but prospective data are lacking in this population."
To test these hypotheses, the researchers studied menstrual cycle length, ovulation occurrence, and seizure frequency in 100 women during the baseline phase of a larger multi-center study on the use of progesterone for modulation of seizures. Over a three-month period the women recorded menstrual cycle length and seizure occurrence. A rise in progesterone during the middle of the cycle signaled ovulation. The frequency of seizures during cycles with ovulation and cycles where no ovulation occurred was compared in the 30 women who had at least one of each type of cycle during the study.
Ovulation occurred in 90 percent of 26-32 day cycles, but declined steeply when cycles were either longer or shorter, occurring in less than 40 percent of either 23- or 35-day cycles. Seizures occurred on average about every four days in ovulatory cycles, and every three days in anovulatory cycles.
"These results support the hypothesis that seizure frequency is affected by ovulation," said Herzog, "and ovulation is correlated with cycle length."
This study was supported by the National Institutes of Health.
The American Academy of Neurology, an association of more than 19,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer disease, epilepsy, multiple sclerosis, Parkinson disease, and stroke.
For more information about the American Academy of Neurology, visit http://www.aan.com.
Editor's Note: Dr. Herzog will present this research during a scientific poster session between 3:00 p.m. and 7:00 p.m. on Thursday, April 6 in the Sails Pavilion of the San Diego Convention Center.
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