Expulsion and continuation rates of the 52 mg levonorgestrel intrauterine system in adolescents and adult women.

Objective: To compare the continuation rates, expulsion, and other reasons for discontinuation of the hormonal intrauterine device with 52 mg of levonorgestrel (52 mg LNG-IUD) in adolescents and adult women.

Methods: We conducted a retrospective cohort study that included 393 women in whom we placed a 52 mg LNG-IUD and followed up to 5 years. We created two retrospective cohorts, one with 131 adolescents (aged between 12 and 19 years) and the other with 262 women aged ≥20 years. Each adolescent was paired with two adult women who had the same parity and who had a 52 mg LNG-IUD inserted on the same day. We used the Mann-Whitney test to compare numerical variables in both groups, the Kaplan-Meier method, and the log-rank test to compare the continuation, expulsion and other reasons for IUD discontinuation of the two groups.

Results: Age of the adolescents and adult women were mean ± SD 18.1 (±1.1) and 31 (±6.8) years, respectively (p = 0.015). Continuation rates by the fifth year of use were 55.6/100 women-years (W-Y) and 70.3/100 W-Y among adolescents and adult women (p = 0.106); and expulsion rates were 8.4/100 and 6.0/100 W-Y, respectively (p = 0.463). Adolescents had a lower continuation rate during 3 to 5 years of follow-up (p = 0.011) and a high rate of removals due to bleeding/pain (18.5 ± 5.7/100 W-Y vs 6.4/100 ± 2.1 W-Y, p = 0.039).

Conclusion: Adolescents who used the 52 mg LNG-IUD showed a lower continuation rate 3-5 years after device placement than adult women. The expulsion rates were similar in both groups.