Objective To compare bone mineral density(BMD) between users of intramuscular depot medroxyprogesterone acetate(DMPA) and nonhormonal control subjects.Methods The study included 87 women aged between 19 and 24 years using DMPA(DMPA group) for 24 months and 83 same-age women using nonhormonal contraception as control group. BMD of the lumbar spine and femoral neck were measured using dual-energy X-ray absorptiometry, comparing mean BMD changes in DMPA group with the control.Results After 24 months of DMPA treatment, as compared with baseline, the mean BMD in lumbar spine and femoral neck were decreased by 2.67% and 2.71%, respectively.The mean lumbar spine and femoral neck BMD in DMPA group at 24 months were not significantly different compared with baseline(P=0.080 and P=0.076, respectively). In comparison, in control group, there was a trend toward increasing BMD. After 24 months of observation, the mean percentage changes from baseline in lumbar spine and femoral neck BMD were increased by 1.24% and 1.30%, respectively. There was no significantly difference compared with baseline(P=0.436 and P=0.373, respectively).Mean BMD at the spine and femoral neck did not differ significantly between DMPA users and nonusers over 12 months(P=0.153 and P=0.140, respectively), but the BMD at both anatomical sites was significantly lower in DMPA group than in the controlafter 24 months of treatment(P=0.012 and P=0.008, respectively).Conclusion The use of DMPA for short-term(≤12-month) had no significant effects on BMD at spine and femoral neck, but long-term exposure to DMPA had significant loss in BMD in women aged between 19 and 24 years. Objective To compare bone mineral density (BMD) between users of intramuscular depot medroxyprogesterone acetate (DMPA) and nonhormonal control subjects. Methods The study included 87 women aged between 19 and 24 years using DMPA (DMPA group) for 24 months and 83 same-age women using non-hormonal contraception as control group. BMD of the lumbar spine and femoral neck were measured using dual-energy X-ray absorptiometry, comparing mean BMD changes in DMPA group with the control. Results after 24 months of DMPA treatment, as compared with baseline , the mean BMD in lumbar spine and femoral neck were decreased by 2.67% and 2.71% respectively.The mean lumbar spine and femoral neck BMD in DMPA group at 24 months were not significantly different compared with baseline (P = 0.080 and P = 0.076 , respectively) in control group, there was a trend toward increased BMD. After 24 months of observation, the mean percentage changes from baseline in lumbar spine and femoral neck BMD were increa sed by 1.24% and 1.30%, respectively. There was no significant difference compared with baseline (P = 0.436 and P = 0.373, respectively) .Mean BMD at the spine and femoral neck did not differ significantly between DMPA users and nonusers over 12 months (P = 0.153 and P = 0.140, respectively), but the BMD at both anatomical sites was significantly lower in DMPA group than in the controlafter 24 months of treatment (P = 0.012 and P = 0.008, respectively) .Conclusion The use of DMPA for short-term (≤12-month) had no significant effects on BMD at spine and femoral neck, but long-term exposure to DMPA had significant loss in BMD in women aged between 19 and 24 years.