Eligible subjects will be hemodynamically stable, menstruating women aged 12-55, who have bone marrow failure, or are undergoing chemotherapy and/or stem cell transplantation for other diseases with platelet levels less than 50,000/ microliter and present with heavy menstrual bleeding which is expected to last at least 2 weeks. Subjects will be randomized to either continuous OCP (Lo-ovral) 1 tablet twice daily or placebo twice daily for one week. All subjects will receive platelet transfusions to keep platelet levels above 20,000 per microliter throughout the study. After one week, all subjects who continue to bleed will receive continuous OCP 1 tablet twice daily. Those who have stopped bleeding will receive continuous OCP 1 tablet daily. Treatments will be compared for the proportion who stop vaginal bleeding 7 and 14 days after starting treatment.