While there may be a decrease in the total number of bleeding days women experience with
continuous-dosed COCs (no menstrual withdrawal week), these regimens frequently result in an
increased number of “breakthrough” or non-scheduled bleeding days. Breakthrough bleeding is
among the main reasons cited for discontinuation of combined COCs dosed traditionally (3
weeks of active pill, 1 week of placebo) or continuously, and may offset the perceived
benefit of fewer withdrawal bleeding events for many women taking continuous-dosed COCs.
The exact mechanisms responsible for breakthrough bleeding patterns during hormonal
contraception are unknown and may be related to the pill formulation. This study is to
determine whether progestin type or estrogen dose influences bleeding patterns, side
effects, or satisfaction with combined oral contraceptives (COC) dosed continuously.
- Age > 18 to 49 years old
- Good general health
- No medical contraindications to combined COC therapy.
- In addition, all participants were required to have taken cyclic COCs for at least
three months at the time of enrollment, in order to avoid common transition bleeding
with the initiation of COCs.