Menopausal bone loss in long-term users of depot medroxyprogesterone acetate contraception.

Abstract

The purpose of this study was to determine the rate of early postmenopausal bone loss in women who had used depot medroxyprogesterone acetate contraception through to menopause. Bone mineral density at the lumbar spine and femoral neck was assessed prospectively over 3 years in 15 women who reached a natural menopause and who did not undergo hormone replacement therapy and in 16 long-term users of depot medroxyprogesterone acetate who discontinued depot medroxyprogesterone acetate only on reaching menopause. Of the latter, 5 women subsequently underwent hormone replacement therapy. Early menopausal bone loss was rapid in the control group (6% from both sites over 3 years), but the users of depot medroxyprogesterone acetate (who did not take hormone replacement therapy) showed little change in bone mineral density. Between-group differences were statistically significant at years 2 and 3 at both sites (P <.03-<.002). In the users of depot medroxyprogesterone acetate who underwent hormone replacement therapy, bone mineral density increased significantly (P <.03) at the lumbar spine and was stable at the femoral neck. Women who use depot medroxyprogesterone acetate through to menopause have attenuated rates of bone loss from the lumbar spine and femoral neck, presumably because they have already lost the estrogen-sensitive component of bone.