Weight change at 12 months in users of three progestin-only contraceptive methods

Background Concerns about weight gain may influence contraceptive use. We compared the change in body weight over the first 12 months of use between women using the etonogestrel (ENG) implant, the levonorgestrel intrauterine system (LNG-IUS) or depot medroxyprogesterone acetate (DMPA) with women using the copper intrauterine device (IUD). Study Design This was a substudy of the Contraceptive CHOICE Project, a prospective cohort study of 9256 women provided no-cost contraception. Women who had been using the ENG implant, LNG-IUS, DMPA or copper IUD continuously for at least 11 months were eligible for participation. We obtained body weight at enrollment and at 12 months and compared the weight change for each progestin-only method to the copper IUD. Results We enrolled a total of 427 women: 130 ENG implant users, 130 LNG-IUS users, 67 DMPA users and 100 copper IUD users. The mean weight change (in kilograms) over 12 months was 2.1 for ENG implant users [standard deviation (SD)=6.7]; 1.0 for LNG-IUS users (SD=5.3); 2.2 for DMPA users (SD=4.9) and 0.2 for copper IUD users (SD=5.1). The range of weight change was broad across all contraceptive methods. In the unadjusted linear regression model, ENG implant and DMPA use were associated with weight gain compared to the copper IUD. However, in the adjusted model, no difference in weight gain with the ENG implant, LNG-IUS or DMPA was observed. Only Black race was associated with significant weight gain (1.3 kg, 95% confidence interval=0.2-2.4) when compared to other racial groups. Conclusions Weight change was variable among women using progestin-only contraceptives. Black race was a significant predictor of weight gain among contraceptive users.