Effects of the long-term use of depot medroxyprogesterone acetate as hormonal contraceptive on bone mineral density and biochemical markers of bone remodeling.

PURPOSE AND METHOD

Our objective is to evaluate the effects of the long-term use of depot medroxyprogesterone acetate (DMPA) as a method of contraception on bone mineral density (BMD) and bone remodeling. Forty women (21-44 years old) who used DMPA for contraception for <1, 1-2 and >5 years, in addition to 20 age-matched healthy women (nonusers), participated in this study. Lumbar spine BMD (LS-BMD) was measured by dual-energy X-ray absorptionmetry. Serum osteocalcin (OC), a bone formation marker, was measured by enzyme amplification sorbent immunoassay. Urinary deoxypyridinoline (DPD), a bone resorption marker, was determined by enzyme immunoassay.

RESULTS

Serum OC and urinary DPD levels in women who used DMPA for <1, 1-2 and >5 years were significantly increased compared to the corresponding levels in nonusers. The increase of both biomarkers was more pronounced with longer duration of use. LS-BMD was significantly decreased in women on long-term DMPA use compared to LS-BMD in nonusers. The mean percentage decrease of LS-BMD in women who used DMPA for 1-2 and >5 years was 9% and 11.8%, respectively. LS-BMD was negatively correlated with serum OC and urinary DPD in women who used DMPA. On the other hand, LS-BMD and bone turnover were not significantly different between women who used DMPA for <1 year and nonusers.

CONCLUSION

Long-term use of DMPA (>2 years) had a significant adverse effect on BMD and induced increased bone turnover, as evidenced by a significant increase in biochemical indices of bone formation and resorption. The measurement of LS-BMD and of biomarkers of bone turnover may be recommended in women aged above 40 years and who used DMPA for a long duration (2-5 years).