UC Davis

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.