Immediate start of hormonal contraceptives for contraception: A systematic review

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 immediately with back-up birth control for the first seven days. The immediate-start approach may improve women's access to, and continuation of, hormonal contraception. We examined randomized controlled trials of immediate-start hormonal contraception for differences in effectiveness, continuation, and acceptability. We searched computerized databases for trials of immediate-start hormonal contraceptives, and contacted researchers to find other studies. We included trials that examined immediate start versus conventional start of hormonal contraception and trials that compared immediate start of different hormonal contraceptive methods with each other. The Peto odds ratio was calculated for the dichotomous variables. Five studies were included. Method discontinuation, bleeding patterns, and side effects were similar between immediate and conventional start groups. A large trial of immediate versus conventional start of oral contraceptives showed pregnancy rates were similar. In a study of depot medroxyprogesterone acetate (DMPA), immediate start resulted in fewer pregnancies than a 'bridge' method before DMPA. More women in the immediate-DMPA group were very satisfied versus those with a 'bridge' method. A trial of immediate ring versus immediate oral contraceptives showed fewer bleeding problems and side effects with the ring. Limited evidence is available regarding whether immediate start of hormonal contraception reduces unintended pregnancies or increases method continuation. More studies with better follow up are needed for immediate versus conventional start of the same hormonal contraceptive.