title: 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.
  
  
  METHODS
  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.
authors.affiliation: Department of Obstetrics and Gynecology, University of Florida College of Medicine-Jacksonville, Jacksonville, FL 32209, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kaunitz
authors.forename: David J
authors.initials: DJ
authors.lastname: Portman
authors.forename: Howard
authors.initials: H
authors.lastname: Hait
authors.forename: Kathleen Z
authors.initials: KZ
authors.lastname: Reape