BACKGROUND: Assess weight variations in Brazilian users of the 20 µg/day levonorgestrel-releasing intrauterine system (LNG-IUS, Mirena®) for comparison with a cohort of users of the TCu 380A intrauterine device (IUD) and a cohort of users of the injectable contraceptive, depot-medroxyprogesterone acetate (DMPA) over a period of five years. METHODS: A total of 163 users of the LNG-IUS, who had the device inserted in 1998, were admitted to the study. At the time of enrollment, each woman was matched by weight (± 1kg) and age (± 1year) to a woman using a TCu 380A IUD and to another woman using DMPA. All women were followed up for a period of five years. Each year weight was measured and the body mass index (BMI, kg/m²) was calculated. RESULTS: Age of the LNG-IUS users was 27.0 ± 6.7 years (mean ± SD), while age of the copper IUD users was 28.0 ± 6.6 years and that of DMPA users was 26.9 ± 6.5 years. Weight recorded at the onset of the study was 62.9 ± 0.8 kg, 62.8 ± 0.8 kg, and 62.5 ± 0.9 kg (Mean ± SD) for users of the LNG-IUS, the copper IUD, and DMPA, respectively. The BMI of women was initially 25.0 (±0.3), 26.4 (±0.3), and 25.5 (±0.4), (Mean ± SD), for users of the LNG-IUS, copper IUD, and DMPA, respectively. Weight increases of 3.1 kg, 4.9kg and 8.2kg were observed at the end of the fifth year among users of the LNG-IUS, copper IUD, and DMPA, respectively (p = 0.009). Increase of the BMI was also observed among all groups (final BMI was 26.3 ± 0.7, 28.5 ± 0.8 and 28.7 ± 1.3 for users of the LNG-IUS, copper IUD and DMPA, respectively). Multivariate analysis showed that there was a significant association between weight increase and length of use of the contraceptive method and of the DMPA. CONCLUSION: The use of a LNG-IUS during five years caused no significant weight increase and the difference in weight was of the same magnitude as that of copper IUD users.
Weight; Levonorgestrel intrauterine system; Body mass index
