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

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.