REAL-WORLD CONTRACEPTIVE FAILURE RATES OF MULTIPLE METHODS OVER THREE YEARS: FINDINGS FROM THE HER SALT LAKE CONTRACEPTIVE INITIATIVE — A PROSPECTIVE COHORT STUDY

Objectives

The HER Salt Lake Contraceptive Initiative provided no-cost contraceptive options for up to three years at four family planning clinics in Salt Lake County, UT. In this analysis, we assess real-world contraceptive failure rates as reported by HER Salt Lake participants.

Methods

Survey data were collected at nine time points over 36 months to assess user experiences, including switching, discontinuation, and pregnancy experiences among individuals using the implant, copper IUD, hormonal IUD, pills, ring, injectable, and nonhormonal behavioral methods. We calculated incidence ratios and 95% confidence intervals for contraceptive failures at 1, 2, and 3 years, as well as cumulative incidence failure rates based on reported person-years among continuers for each of these methods.

Results

Among 4,278 individuals, there were 91 unintended pregnancies that occurred while contracepting. Hormonal IUDs had the overall lowest cumulative incidence failure rate (incidence rate (IR), 0.006/person-year; 95% CI, 0.004–0.011), followed by the implant (IR, 0.008/person-year; 95% CI, 0.005–0.016), copper IUD (IR, 0.011/person-year; 95% CI, 0.006–0.019), injectable (IR, 0.014/person-year; 95% CI, 0.006–0.025), ring (IR, 0.019/person-year; 95% CI, 0.007–0.044), pills (IR, 0.022/person-year; 95% CI, 0.016–0.031) and nonhormonal behavioral methods (IR, 0.05/person-year; 95% CI, 0.016–0.148).

Conclusions

Three-year failure rates in real-world settings are rarely published. The HER participants received their preferred methods and reported lower typical-use failure rates across methods compared to currently published information. While participation in research may influence behaviors, data from contraceptive initiatives that prioritize patient preference add important context when discussing contraceptive effectiveness over time. Our findings provide encouraging data for contraceptive access initiatives committed to offering the full range of contraceptive options and support the effectiveness of all methods.