Long-acting injectable progestin contraception and risk of type 2 diabetes in Latino women with prior gestational diabetes mellitus.

OBJECTIVE To investigate the impact of a long-acting injectable progestin, depo-medroxyprogesterone acetate (DMPA), compared with combination oral contraceptives (COCs) on the risk of diabetes in Latino women with prior gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS An observational cohort study of 526 Hispanic women with prior GDM who were not diabetic in their postpartum visit during January 1987 to October 1997 and who elected DMPA (n = 96) or COCs (n = 430) as initial contraception were followed for a maximum of 9.2 years with a median follow-up of approximately 12 months. Oral glucose tolerance tests were performed and choice of contraception method was recorded at each visit as part of routine clinical care. RESULTS Annual diabetes incidence rates were 19% in the DMPA group and 12% in the COC group, with an unadjusted hazard ratio (HR) of 1.58 (95% CI 1.00-2.50; P = 0.05) for DMPA compared with COCs. Adjustment for baseline imbalances reduced the HR to 1.18 (0.67-2.28; P = 0.57). Additional adjustment for weight gain during follow-up, which was on average 1.8 kg higher in the DMPA group (P < 0.0001), reduced the HR to 1.07. DMPA interacted with baseline serum triglyceride levels and, separately, with breast-feeding to increase the diabetes risk. CONCLUSIONS DMPA use was associated with an increased risk of diabetes that appeared to be explained by three factors: 1) use in women with increased baseline diabetes risk, 2) weight gain during use, and 3) use with high baseline triglycerides and/or during breast-feeding.