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Obstet Gynecol. 2015 Mar;125(3):599-604. doi: 10.1097/AOG.0000000000000690.

Use of the etonogestrel implant and levonorgestrel intrauterine device beyond the U.S. Food and Drug Administration-approved duration.

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Division of Clinical Research, Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine, St. Louis, Missouri.



To evaluate the effectiveness of the contraceptive implant and the 52-mg hormonal intrauterine device (IUD) in women using the method beyond the current U.S. Food and Drug Administration (FDA)-approved duration of 3 and 5 years, respectively.


Women willing to continue using their implant or 52-mg levonorgestrel IUD beyond the FDA-approved duration were followed prospectively for contraceptive effectiveness. Unintended pregnancy rate per 100 women-years was calculated. Implant users are offered periodic venipuncture for analysis of serum etonogestrel levels. The Kruskal-Wallis test was used to compare the etonogestrel levels across body mass index (BMI) groups.


Implant users (n=237) have contributed 229.4 women-years of follow-up, with 123 using the etonogestrel implant for 4 years and 34 using it for 5 years. Zero pregnancies have been documented, for a failure rate of 0 (one-sided 97.5% confidence interval [CI] 0-1.61) per 100 women-years. Among 263 levonorgestrel IUD users, 197.7 women-years of follow-up have been completed. One pregnancy was confirmed, for a failure rate of 0.51 (95% CI 0.01-2.82) per 100 women-years. Among implant users with serum etonogestrel results, the median and range of etonogestrel level at 3 years of use was 188.8 pg/mL (range 63.8-802.6 pg/mL) and 177.0 pg/mL (67.9-470.5 pg/mL) at 4 years of use. Etonogestrel levels did not differ by BMI at either time point (3 years: P=.79; 4 years: P=.47).


Preliminary findings indicate the contraceptive implant and 52-mg hormonal IUD continue to be highly effective for an additional year beyond the FDA-approved 3 and 5 years. Serum etonogestrel levels indicate the implant contains adequate hormone for ovulation suppression at the end of both 3 and 4 years of use.



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