Table 1 Changes in oral contraceptives done to increase efficacy, improve safety, get better control of bleeding and obtain decreased bleeding

Introduction of biphasic and triphasic COCP regimens

Continuous COCP regimens

Change from 21–7 to 24–4 COCP regimens [less pill free days, less days of unopposed estrogen]

Addition of 2 days of estrogen during “pill free period” to control bleeding 24–2-2 regimen

Lower estrogen dose

Increased progestin dose

Use of various new progestins

Various other COCP regimens

High dose progestin-only pills