Abstract: We found 22 eligible studies that included a total of 11,450 women. With 6 NRS added to this update, the review includes 17 NRS and 5 RCTs. By contraceptive method, the review has 16 studies of depot medroxyprogesterone acetate (DMPA), 4 of levonorgestrel-releasing intrauterine contraception (LNG-IUC), 5 for implants, and 2 for progestin-only pills. Comparison groups did not differ significantly for weight change or other body composition measure in 15 studies. Five studies with moderate or low quality evidence showed differences between study arms. Two studies of a six-rod implant also indicated some differences, but the evidence was low quality. Three studies showed differences for DMPA users compared with women not using a hormonal method. In a retrospective study, weight gain (kg) was greater for DMPA versus copper (Cu) IUC in years one (MD 2.28, 95% CI 1.79 to 2.77), two (MD 2.71, 95% CI 2.12 to 3.30), and three (MD 3.17, 95% CI 2.51 to 3.83). A prospective study showed adolescents using DMPA had a greater increase in body fat (%) compared with a group not using a hormonal method (MD 11.00, 95% CI 2.64 to 19.36). The DMPA group also had a greater decrease in lean body mass (%) (MD -4.00, 95% CI -6.93 to -1.07). A more recent retrospective study reported greater mean increases with use of DMPA versus Cu IUC for weight (kg) at years 1 (1.3 vs 0.2), 4 (3.5 vs 1.9), and 10 (6.6 vs 4.9). Two studies reported a greater mean increase in body fat mass (%) for POC users versus women not using a hormonal method. The method was LNG-IUC in two studies (reported means 2.5 versus -1.3; P = 0.029); (MD 1.60, 95% CI 0.45 to 2.75). One also studied a desogestrel-containing pill (MD 3.30, 95% CI 2.08 to 4.52). Both studies showed a greater decrease in lean body mass among POC users. We considered the overall quality of evidence to be low; more than half of the studies had low quality evidence. The main reasons for downgrading were lack of randomizations (NRS) and high loss to follow-up or early discontinuation. These 22 studies showed limited evidence of change in weight or body composition with use of POCs. Mean weight gain at 6 or 12 months was less than 2 kg (4.4 lb) for most studies. Those with multiyear data showed mean weight change was approximately twice as much at two to four years than at one year, but generally the study groups did not differ significantly. Appropriate counseling about typical weight gain may help reduce discontinuation of contraceptives due to perceptions of weight gain.

Plain-language summary: Until 4 August 2016, we did computer searches for studies of a POC compared with another birth control method or no contraceptive. For the initial review, we wrote to investigators to find other trials. The focus was on change in body weight or other body measure of lean or fat mass.  With six new studies in this update, we have 22 studies that included 11,450 women. The groups compared did not differ much for weight change or other body measures in 15 studies. Five studies with moderate or low quality results showed a difference between study groups. Three studies showed differences for users of the injectable ‘depo’ versus no hormonal method. Depo users had a greater weight gain in two studies. In the third study, adolescents had a greater increase in body fat (%) and decrease in lean body mass (%). Two studies showed a greater increase in body fat (%) for users of hormonal intrauterine contraception versus women not using a hormonal method. One also showed a similar difference with a progestin-only pill. Both studies showed a greater decrease in lean body mass with POC use.  We found little evidence of weight gain when using POCs. Mean weight gain at 6 or 12 months was less than 2 kg (4.4 lb) for most studies. The groups using other birth control methods had about the same weight gain. Good counseling about typical weight gain may help women continue using birth control.