A randomized, multicenter comparison of two intrauterine contraceptive devices (IUDs) was carried out. Nine hundred thirty-seven women were fitted with a copper-releasing IUD, the Nova-T, and 1821 women with an IUD that releases 20 jug of levonorgestrel daily. After 36 months, the cumulative gross rates of amenorrhea and hormonal side effects were significantly higher in the levonorgestrel-IUD users. The cumulative 36-month gross pregnancy rate was 3.7 for the Nova-T and 0.3 for the levonorgestrel IUD (P<.001), demonstrating the levonorgestrel IUD's high contraceptive efficacy. For the first time, a protective effect of the levonorgestrel IUD against pelvic inflammatory disease as compared with the Nova-T was seen statistically. The cumulative 36-month gross rate of pelvic inflammatory disease was 2.0 in Nova-T- and 0.5 in levonorgestrel-IUD users (P<.013). This significantly lowered incidence of pelvic inflammatory disease may help to solve one of the major concerns associated with intrauterine contraception.
(C) 1991 The American College of Obstetricians and Gynecologists