Selection and performance of the levonorgestrel-releasing intrauterine system.

BACKGROUND: The levonorgestrel-releasing intrauterine system (LNg IUS) is a hormonal contraceptive that is used in the uterine cavity. To determine whether the reasons for choosing LNg IUS vs. copperreleasing intrauterine devices (Cu IUDs) differ and whether their performances are comparable, we carried out a retrospective study in Finland during the first years of LNg IUS use. METHODS: Gynecological and contraceptive histories of 626 LNg IUS and 626 Cu IUD users and the performance of the device were reviewed from patient records. RESULTS: Women who accepted the LNg IUS were more likely than Cu IUD acceptors to have a history of menstrual bleeding of 6 days or more (44.4% vs. 28.4%), heavy bleeding (44.8% vs. 8.4%) and moderate or severe dysmenorrhea (15.9% vs. 7.5%). In both groups, 70% of the women had used Cu IUDs earlier. However, the LNg IUS acceptors had had more side effects during previous use of CU IUDs (58.2% vs. 28.8%). They also reported more side effects that resulted in discontinuation of a previous Cu IUD (39.4% vs. 10.1%). However, the 12-month life-table continuation rates of 80.6 (SE 1.9)% vs. 83.4 (SE 1.8)% were alike. Cu IUD users discontinued the current method more often because of problems of bleeding and unwanted pregnancy. Among those women who had previously discontinued a hormonal method because of hormonal side effects, there were no differences in the continuation rates of the two groups. CONCLUSIONS: LNg IUS can be successfully used by women who cannot use a CU IUD or who have experienced hormonal side effects with oral contraceptives.