Evidence about extending the duration of oral contraceptive use to suppress menstruation

Introduction: For many years, individual women and doctors have experimented with extending the duration of active oral contraceptive (OC) pills between pill-free intervals (long OC) to control menstruation. The U.S. approval of an OC with 84 active days and 7 pill-free days in 2003 has attracted considerable media attention. In this review we consider the published evidence on the effectiveness, side effects, and risks of menstrual suppression with long OC. Methods: We performed a systematic review of published literature on long OC, up to April 2003. Results: Ten papers were located; two were randomized trials comparing long OC to standard OC; the remaining studies were single-group observational studies. Women on long OC schedules had fewer days of scheduled bleeding during days without pills but more days of unscheduled bleeding and spotting than those on standard OC. These problems were worse for women new to OC and diminished over time. Women on long OC were more likely to discontinue due to poor control of bleeding; women on standard OC were more likely to stop because of problems with headaches. Women on long OC and standard OC both showed increases in physiological factors related to clotting, with a nonsignificant tendency for those on long OC to be more affected. No studies considered the effects of long OC on breast tissue, breast density, endometrial safety, or adolescent maturation and reproductive development. No systematic data were available on the return to reproductive function and fertility after taking long OC. There were no placebo-controlled trials and no information on how long OC compares to normal, unmedicated menstrual cycles. Therefore we believe scientific evidence for safety of long OC use is presently lacking.