American women are taught, and doctors generally assume, that the “normal” pattern of the reproductive cycle is to menstruate every 28 days, plus or minus a few. Of course certain things, such as pregnancy, can interrupt that cycle but the general assumption has been that on average women bleed thirteen times a year for their entire reproductive life. Indeed, the 28 day oral contraceptive regimen was intentionally designed to mimic a “normal” reproductive cycle. The Sahel reg