Six-year contraceptive efficacy and continued safety of a levonorgestrel 52 mg intrauterine system

Carolyn L. Westhoff, Lisa M. Keder, Angelina Gangestad, Stephanie B. Teal, Andrea I. Olariu, Mitchell D. Creinin

Research output: Contribution to journalArticle


Objective: To assess 6-year contraceptive efficacy and safety of a levonorgestrel 52 mg intrauterine system (IUS). Study Design: We assessed pregnancy rates through 72 months in women aged 16–35 years at enrollment and safety in all participants (aged 16–45 years, n = 1751) in an ongoing 10-year phase-3 trial. Results: Over six years, nine pregnancies occurred (none in year 6) for a life-table pregnancy rate of 0.87 (95% CI 0.44–1.70). Adverse event rates remain low through 6 or more years of use. Two expulsions occurred in year 6. Conclusion: This levonorgestrel 52 mg IUS is a highly effective and safe contraceptive over 6 years of use. Implications: The levonorgestrel 52 mg IUS shows high 6-year contraceptive efficacy and a low rate of adverse events through 6 or more years of use.

Original languageEnglish (US)
StateAccepted/In press - Jan 1 2019



  • Efficacy
  • Intrauterine system
  • Levonorgestrel
  • Liletta
  • Safety

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynecology

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