Bone mineral density in young, hypothalamic oligoamenorrheic women treated with oral contraceptives

To evaluate whether decreasing doses of ethinyl estradiol affect bone loss related to hypothalamic amenorrhea.

Sixty-four women with hypothalamic oligoamenorrhea were allocated to two therapy groups: group A (n = 24) received an OC containing 0.030 mg of ethinyl estradiol (EE) and 0.15 mg of desogestrel. Group B (n = 22) received an OC containing 0.020 mg of EE and 0.15 mg of desogestrel. Eighteen women who did not wish to use hormonal therapy constituted the control group (C). Calcium, phosphate and osteocalcin were measured basally and at 6 and 12 months of follow-up. Bone mineral density at the lumbar spine was determined before initiation of the study and at 12 months by dual energy X-ray absorptiometry.

Serum calcium, phosphate and osteocalcin were significantly reduced by both active treatment regimens, whereas no differences were observed in the control group. Bone mineral density at 12 months showed an increase in both therapy groups (A, 2.4%; B, 2.5%), while group C showed a significant decrease (1.2%, P < .05).

Both doses of EE were equally effective in preventing bone loss related to hypoestrogenism in hypothalamic oligoamenorrheic subjects.