Clinical Edge

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Efficacy of a Levonorgestrel 52-mg IU System

Obstet Gynecol; ePub 2018 Dec 4; Teal, et al

In a cohort of US females, a levonorgestrel (LNG) 52-mg intrauterine system (IUS) showed high 5-year contraceptive efficacy and low hormonal adverse effect rates, according to a phase 3 study. Researchers enrolled 1,751 nulliparous and parous females aged 16‒45 years and desiring contraception to receive a novel LNG 52-mg IUS at 29 centers in the US. Participations had scheduled follow-up visits 4 times during the first year; every 6 months after year 1. The primary outcome was pregnancy rate at enrollment through 60 months. Among the findings:

  • The 1,751 enrollees included 1,600 females aged 16‒35 years and 151 aged 36‒45 years.
  • Successful IUS placement occurred in 1,714 (97.9%) participants.
  • 495 participants finished 5 years and 176 had entered the seventh year of IUS use at the time of data evaluation.
  • The cumulative life-table pregnancy rate was 0.92% through 5 years.
  • Discontinuation for adverse events occurred in 322 (18.8%) participants, most commonly related to expulsion.


Teal SB, Turok DK, Chen BA, Kimble T, Olariu AI, Creinin MD. Five-year contraceptive efficacy and safety of a levonorgestrel 52-mg intrauterine system. [Published online ahead of print December 4, 2018]. Obstet Gynecol. doi:10.1097/AOG.0000000000003034.