Objective: To compare bleeding patterns after immediate vs. conventional oral contraceptive (OC) initiation.
Design: Randomized controlled trial.
Setting: University-based clinic.
Patient(s): One hundred thirteen women initiating combination OCs.
Intervention(s): Participants received a 4-month supply of a monophasic 35-microg ethinyl E(2) (EE) OC and a bleeding diary, were randomized to immediate or conventional OC start, underwent monthly telephone follow-up, and after 90 days returned the diary and completed an exit interview.
Main outcome measure(s): Total number of bleeding-spotting days, using the World Health Organization 90-day reference period method. Comparisons were made by trial assignment (immediate vs. conventional) and cycle day of OC initiation (day 8+ vs. days 1-7).
Result(s): There was no significant difference in the number of bleeding-spotting days (mean difference: -0.5 days; 95% CI: -3.4 to 2.3) or any other bleeding parameter between the immediate and conventional starters, or days 1-7 and day 8+ starters.
Conclusion(s): Immediate start of OCs does not induce bleeding patterns different from conventional starting regimens. Concern about adverse bleeding patterns should not be considered a justification for instructing women to wait until menses before starting OCs.