Immediate start of hormonal contraceptives for contraception.

Health care providers often tell women to wait until the next menses to begin hormonal contraception. The intent is to avoid contraceptive use during an undetected pregnancy. An alternative is to start hormonal contraception immediately with back-up birth control for the first seven days. Immediate initiation was introduced with combined oral contraceptives (COCs), and has expanded to other hormonal contraceptives. At the time of the initial review, how immediate start compared to conventional menses-dependent start was unclear regarding effectiveness, continuation, and acceptability. The immediate-start approach may improve women's access to, and continuation of, hormonal contraception.