Long-term contraception with the levonorgestrel 20 mcg/day (LNg 20) and the Copper T 380Ag intrauterine devices: A five-year randomized study

Abstract 

An intrauterine device, releasing approximately 20 μg/day of levonorgestrel (LNg 20), used by 1124 women, was studied in a randomized trial of five years duration in comparison with the Copper T, model TCu 380Ag, in 1121 women. At five years, the gross cumulative pregnancy rate of 1.1±0.5 per 100 among users of the LNg 20 devices was not significantly different from the rate of 1.4±0.4 per 100 experienced by users of the Copper T 380Ag. The steroid-releasing IUD had significantly higher termination rates for expulsion and amenorrhea, a significantly lower termination rate for other menstrual problems and pain, and a lower continuation rate. The five-year continuation rate among women using the TCu 380Ag was 40.6 per 100 as compared with that of 33.0 per 100 among women randomized to the LNg 20 device (P < .001). Terminations attributed to amenorrhea with the LNg device primarily account for differences in continuation.

These two Intrauterlne devices are the most effective long-term, reversible IUDs yet reported in the literature. No other contraceptive methods have exhibited such low long-term pregnancy rates in randomized comparative trials.

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