There is, however, another option for female astronauts and that’s not having periods at all. Properly called medically induced amenorrhea, it's possible to suppress menstruation by messing with the body’s natural hormones, which is what some birth control methods do. The combined oral contraceptive pill is taken daily. For 21 days the pills contain an active ingredient that suppresses ovulation and thins the uterine lining. The fourth week is 7 days of a placebo pill that allows the body to go through withdrawal bleeding, which is different than menstruation. Taking the active pill for a full month, or many months, completely stops any bleeding (though there might be light spotting).