Robert L. Barbieri, MD reviewing McNicholas C et al. Am J Obstet Gynecol 2017 Jan 29.

The etonogestrel implant and the 52-mg LNG-IUD continued to be highly effective beyond the FDA-approved timeframes.

The most effective reversible contraceptives are the etonogestrel subdermal implant and the 52-mg levonorgestrel intrauterine device (LNG-IUD). The FDA has approved the etonogestrel implant (Nexplanon) and the 52-mg LNG-IUD (Mirena) for 3 and 5 years of use, respectively. To investigate contraceptive effectiveness beyond these timeframes, researchers conducted a manufacturer-supported observational study involving 291 women who had already used the implant for 3 years and 496 who had used the LNG-IUD for 5 years.

During the 2-year study, no pregnancies occurred in the implant group. The calculated failure rate was 0 per 100 women-years (one-sided 97.5% confidence interval, 0–1.48) in year 4 of use and 0 per 100 women-years (one-sided 97.5% CI, 0–2.65) in year 5 of use. Two pregnancies occurred in the LNG-IUD group. The calculated failure rate in year 6 of use was 0.25 per 100 women-years (95% CI, 0.04–1.42) and in year 7 of use was 0.43 per 100 women-years (95% CI, 0.08–2.39).

CITATION(S):

McNicholas C et al. Prolonged use of the etonogestrel implant and levonorgestrel intrauterine device — two years beyond FDA-approved duration. Am J Obstet Gynecol 2017 Jan 29; [e-pub]. 

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