Calendar 'Rhythm' Method Undermined
By Wide Cycle Ranges
The calendar method of fertility control may be dependable for only 30% of women in menacme, a Georgetown University study indicates.Menstrual cycle length was so variable among 2,316 women studied that only three in ten had menstrual cycles that varied consistently by less than eight days, said Franklin T. Brayer, MD, of Georgetown's Center for Population Research and Department of Community Medicine and International Health.If a woman is to use the calendar rhythm method with any success, eight to ten days is the generally accepted limit for her menstrual cycle to vary over a several-month period, Dr. Brayer said.In this study, data on 30,655 cycles were obtained from the 2,316 women, predominantly Roman Catholic, in the United States and Canada. Each woman was followed for at least ten cycles. No cycles were recorded within six months postpartum.