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Long-acting contraception associated with low failure

Clinical Question:
How do the failure rates of long-acting reversible contraception methods compare with the pill, patch, and ring?

Bottom Line:
The contraceptive failure rate with intrauterine devices (IUDs) and implants is much lower than failure rates with contraceptive pills, patches, and rings. The IUD and implant failure rate was similar to that of depot medroxyprogesterone acetate (DMPA). The absolute difference in this study was approximately 4 pregnancies per 100 women-years of use. (LOE = 2b)

Winner B, Peipert JF, Zhao Q, et al. Effectiveness of long-acting reversible contraception. N Eng J Med 2012;366(21):1998-2007.  [PMID:22621627]

Study Design:
Cohort (prospective)


Outpatient (primary care)

This was a prospective cohort study that enrolled 9256 women aged 14 to 45 years with a stated purpose of promotion of long-acting contraceptive methods (IUDs and implants). Eligible women were either not using a contraceptive method or were willing to change, did not want to become pregnant in the next year, were sexually active with a male partner or planning to become so within the next 6 months. Women were read a script that asserted that IUDs and implants were the most effective contraceptive method and they were counseled regarding the effectiveness, risks, and benefits of all reversible methods. Women then chose a method which was provided at no cost for 2 to 3 years, depending on the time of enrollment. Women could discontinue or switch methods as often as they wished. Women were interviewed at 3 months and 6 months, then every 6 months throughout the follow-up period. Periods of long-acting contraception were compared with use of pill, patch, ring, and DMPA. Periods of use of other methods, such as condoms or diaphragms, were excluded. Participants who thought they were pregnant were asked to come in for a urine pregnancy test. Contraceptive failure was defined as pregnancy occurring during use, but not if the participant stated that she had discontinued the method. If an IUD had been expulsed, pregnancy was considered to be a contraceptive failure if the woman was not aware of the expulsion. Use was measured in months and then expressed in woman-years. Overall failure rates with pill, patch, or ring were 4.8%, 7.8%, and 9.4% in years 1, 2, and 3, respectively. Failure rates with IUD or implant were 0.3%, 0.6%, and 0.9% in years 1, 2,and 3, respectively. Failure rates with DMPA were similarly low at 0.1%, 0.7%, and 0.7%. Overall failure rates per 100 woman-years were 4.6 with the pill, patch, or ring; 0.2 with DMPA; and 0.3 with an IUD or implant. The calculated hazard ratio for failure of long-acting methods compared with pill, patch, or ring after adjustment for age, education level, and number of previous unintended pregnancies was 22 (95% CI, 14-35). In subgroup analysis, women younger than 21 years using the pill, patch, or ring were twice as likely to have an unintended pregnancy as older women using those methods.


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