Almost 14% of adolescent girls gave birth before age 18 and 18% of all births worldwide are of adolescents’ girls.1,2 It is estimated that the worldwide adolescent pregnancy rate is 46 births per 1,000 girls, and Latin America and the Caribbean region accounted for the second highest rate in the world, estimated at 66.5 births per 1,000 girls aged 15-19 years. Despite the high numbers, since 2000 a decline of global adolescent birth rate was observed by over 50% among girls aged 10-14 and by over 30% among girls aged 15-19.3 The number of adolescent pregnancies has been decreasing over the years, though not in all settings. In Brazil the proportion of adolescent births was 18% despite a 17% decrease in the year 2015 compared to 2014.4 Pregnancy in adolescence is associated with morbidities, including a higher risk of premature birth, low birth weight, perinatal depression, and hypertensive syndrome when compared to adult women.5 The decline in pregnancy in adolescents is largely due to better access to and use of contraceptive methods,5 although there are still many barriers, mainly in accessing long-acting reversible contraceptive (LARC) methods (implants and intrauterine devices (IUDs),6 leading to millions of unplanned pregnancies.5

The most common IUDs currently in use worldwide include the Tcu380A, with a 380-mm Cu surface and effective for up to 10-12 years after placement,7 various brands of IUDs that contain 52 mg of levonorgestrel, releasing 20 µg/day of the steroid, and two which contain 19.5 mg and 13.5 mg and release 13 and 8 µg/day, respectively, with the same high contraceptive efficacy as the levonorgestrel 52 mg IUD (almost 0.2/100 women-years).8, 9, 10

The contraceptive effectiveness of IUDs is independent of user, age and parity11 and is more effective than short-acting contraceptives such as pills, injectables, patches or vaginal rings, which require periodic attention from women.8 IUDs have some characteristics like few side effects, ease of insertion, even in adolescents, and they may be placed in a single-visit consultation without the need for additional tests, even in the immediate postpartum period.12, 13, 14, 15 Copper-IUDs present high continuation and satisfaction rates16 and non-contraceptive benefits like the reduced risk of cervical and endometrial cancer.17 In addition, the levonorgestrel 52 mg IUD is approved as treatment for women with heavy menstrual bleeding and several studies have shown that this IUD reduces dysmenorrhea (an important benefit among adolescents), provides endometrial protection during estrogen therapy after the menopause,18 and in some cases induces amenorrhea.

Despite the benefits of IUD use, there are barriers posed by many healthcare providers for use in adolescent girls and nulligravidas, and the pain at IUD placement is one of the barriers to use, both from providers and adolescents. However, there is evidence that they were possible to place in adolescents and nulligravidas.8,12 We proposed a hypothesis that because the levonorgestrel 19.5 mg IUD is smaller and thinner than both the TCu380A and the levonorgestrel 52 mg IUDs, the expulsion rate could be lower and the continuation rate could be higher in adolescents when compared to the other two IUDs. As contribution to the body of evidence regarding the use of different IUDs in adolescents, we conducted a randomized clinical trial (RCT) with the primary objectives to assess clinical performance, reasons for discontinuation and continuation rate, and secondary objectives to assess satisfaction with the IUD, dysmenorrhea, and bleeding patterns up to one year after IUD placement of three models of IUDs in adolescents.