Women initially choosing injectable contraception had pregnancy rates similar to oral contraception and significantly worse than intrauterine or implantable contraception. This according to a study that provided reversible contraception to 9,252 women at 2 to 3 years of follow-up. Researchers found:
• During 20,017 woman-years, 615 unintended pregnancies were identified.
• Despite switching and discontinuation, women choosing an intrauterine or implantable contraception at baseline were much less likely to have an unintended pregnancy vs women selecting other methods.
• In intent-to-use (ITU) analysis, pregnancy rates were 5.3, 5.5, 2.0, 1.7 and 1.9 per 100 woman-years for women initiating oral, injectable, implantable, copper and hormonal intrauterine contraception at baseline, respectively.
• Adjusted hazard ratio for injectable compared to hormonal intrauterine contraception was 2.4.
• Delaying initiation of intrauterine or implantable contraception increased unintended pregnancies by 60% (aHR=1.6).
• In as-used analysis, pregnancy rates were 6.7, 1.6, 0.2, 0.6, and 0.2 per 100 woman-years for women using oral, injectable, implantable, copper, and hormonal intrauterine contraception, respectively.
Citation: Reeves MF, Zhao Q, Secura GM, Peipert JF. Risk of unintended pregnancy based on intended compared to actual contraceptive use. [Published online ahead of print January 21, 2016]. Am J Obstet Gynecol. doi: 10.1016/j.ajog.2016.01.162.