Bone mineral density during long-term treatment with Norplant implants and depot medroxyprogesterone acetate. A cross-sectional study of Thai women.

This cross-sectional study compares bone mineral density (BMD) in long-term Norplant implants and depot medroxyprogesterone acetate (DMPA) users. The objectives of this study were to evaluate and compare the bone mineral density between women using these contraceptives. Forty-one current users of Norplant implants and 50 DMPA users participated in the study. The BMD was measured by dual energy x-ray absorptiometry in the nondominant distal and ultradistal forearm. Serum estradiol was measured by microparticle enzyme immunoassay technique. The demographic characteristics were similar in both groups. The mean durations +/- SD of DMPA and Norplant implants were 59.14 +/- 30.73 and 31.1 +/- 11.2 months, respectively. The BMD of long-term Norplant implant and DMPA users was similar. The serum estradiol in the Norplant implant group was significantly higher than in DMPA users. However, the serum estradiol level in DMPA users ranged into normal for the follicular phase, which is higher than for postmenopausal women. This study suggests that two long-acting progestogen contraceptives do not differ with respect to their impact on BMD in long-term users.