ObjectivesTo assess the effect of oral contraception started on the first day of menses and the fifth day following its onset, on women's compliance and the incidence of early breakthrough bleeding.MethodsOral contraceptives (OCs) containing 30μg ethinylestradiol and 75μg gestodene were prescribed to 100 consecutive, healthy women for whom OCs were found to be the most suitable method of contraception. In the first 50 women, OCs were started on the first day of menses (day 1 group), while in the remaining 50 women, OCs were started on the fifth day after the onset of menses (day 5 group).ResultsThe day 5 group had better compliance and a reduced incidence of breakthrough bleeding. No differences were observed between the two groups regarding age, parity and gravity.ConclusionStarting an OC regimen should include initiation on the fifth day following the onset of menses. This regimen might increase patient compliance and lower the incidence of breakthrough bleeding.