Bone mineral density in adolescent females using depot medroxyprogesterone acetate

Study objective To examine bone mineral density (BMD) on a semi-annual basis among control subjects and adolescent females receiving depot medroxyprogesterone acetate (DMPA) injection or oral contraceptives. Design Non-randomized prospective study. Setting Teenage pregnancy prevention intervention clinic. Participants Adolescent females who were new users of DMPA injection (N = 58, age12–21) or the oral contraceptive pill (N = 71, age 11–19) and normal menstruating girls (N = 19, age 15–18). Interventions Baseline and 6-monthly measures of lumbar vertebral BMD using dual-energy X-ray absorptiometry over a 2-year period. Main outcome measures comparison of percent change on BMD over time between DMPA users, pill users, and normal menstruating girls. Results There was no difference on group characteristics at baseline except for the ethnicity between the controls and the DMPA grouup. There was a statistically significant decrease in BMD between DMPA users and controls at 6 months (−3.02% change, P = 0.014) 12 months (−3.38% change, P = 0.001) 18 months (−4.81% change, P<0.001) and 24 months (−6.81% change, P = 0.010). There was no statistical difference between pill users and controls. Conclusion There is a relationship between DMPA use and a decrease in BMD compared to normal menstruating controls that seems to persist up to 24 months.