Adding low-dose estrogen to the hormone-free interval: impact on bleeding patterns in users of a 91-day extended regimen oral contraceptive

Abstract

Background A cross-study analysis of contraceptive clinical trials for two different 91-day oral contraceptive (OC) regimens was performed to examine the impact on bleeding patterns when supplementing the 7-day hormone-free interval with 10 mcg ethinyl estradiol (EE) daily. Study Design Two separate 1-year Phase 3 clinical programs were conducted using similar study designs. The percentages of subjects reporting bleeding and spotting using electronic diaries for each 91-day cycle were compared. Results Scheduled bleeding with the EE regimen was less than that reported with the regimen utilizing placebo during Days 85–91, with significant differences noted for all four 91-day cycles. Unscheduled bleeding decreased more quickly with the 91-day regimen containing low-dose EE in place of placebo, with significant differences noted during the third cycle. Conclusions This cross-study comparison suggests that the administration of low-dose estrogen in place of placebo in a 91-day extended regimen OC improves the bleeding profile.