Three-year Efficacy and Safety of a New 52-mg Levonorgestrel-releasing Intrauterine System

Objective: To assess 3-year data on the efficacy and safety of a new 52-mg levonorgestrel intrauterine contraceptive (LNG20) designed for up to 7 years use.

Study Design: Nulliparous and parous women aged 16-45 years at enrollment with regular menstrual cycles and requesting contraception were enrolled in an open-label, partially randomized trial to evaluate LNG20. The primary outcome was pregnancy rate for women aged 16-35 years calculated as the Pearl Index. Women aged 36-45 years received LNG20 for safety evaluation only. All participants had in-person or phone follow-up approximately every 3 months during the study.

Results: A total of 1600 women aged 16-35 years and 151 women aged 36-45 years agreed to LNG20 placement, including 1011 (57.7%) nulliparous and 438 (25.1%) obese women. Successful placement occurred in 1714 (97.9%) women. Six pregnancies occurred, four of which were ectopic. The Pearl Index for LNG20 was 0.15 (95% CI 0.02-0.55) through Year 1, 0.26 (95% CI 0.10-0.57) through Year 2, and 0.22 (95% CI 0.08-0.49) through Year 3. The cumulative life-table pregnancy rate was 0.55 (95% CI 0.24-1.23) through 3 years. Expulsion was reported in 62 (3.5%) participants, most (50 [80.6%]) during the first year of use. Of women who discontinued LNG20 and desired pregnancy, 86.8% conceived spontaneously within 12 months. Pelvic infection was diagnosed in 10 (0.6%) women. Only 26 (1.5%) LNG20 users discontinued due to bleeding complaints.

Conclusion: The LNG20 intrauterine system is highly effective and safe over 3 years of use in nulliparous and parous women.

Implications Statement: A new 52-mg levonorgestrel-releasing intrauterine system is effective and safe for nulliparous and parous women for at least 3 years.