Bone mineral density in young women with long-standing amenorrhea: Limited effect of hormone replacement therapy with ethinylestradiol and desogestrel

To assess bone mineral density (BMD) at different skeletal sites in women with hypothalamic or ovarian amenorrhea and the effect of estrogen-gestagen substitution on BMD we compared BMD of 21 amenorrheic patients with hypothalamic or ovarian amenorrhea with that of a control population of 123 healthy women. All amenorrheic patients were recruited from the outpatient clinic of the Division of Gynecological Endocrinology at the University of Berne, a public University Hospital. One hundred and twenty-three healthy, regularly menstruating women recruited in the Berne area served as a control group. BMD was measured using dual-energy X-ray absorptiometry (DXA). At each site where it was measured, mean BMD was lower in the amenorrheic group than in the control group. Compared with the control group, average BMD in the amenorrheic group was 85% at lumbar spine (p<0.0001), 92% at femoral neck (p<0.02), 90% at Ward's triangle (p<0.03), 92% at tibial diaphysis (p<0.0001) and 92% at tibial epiphysis (p<0.03). Fifteen amenorrheic women received estrogen-gestagen replacement therapy (0.03 mg ethinylestradiol and 0.15 mg desogestrel daily for 21 days per month), bone densitometry being repeated within 12–24 months. An annual increase in BMD of 0.2% to 2.9% was noted at all measured sites, the level of significance being reached at the lumbar spine (p<0.0012) and Ward's triangle (p<0.033). In conclusion BMD is lower in amenorrheic young women than in a population of normally menstruating, age-matched women in both mainly trabecular (lumbar spine, Ward's triangle, tibial epiphysis) and mainly cortical bone (femoral neck, tibial diaphysis). In these patients, hormone replacement therapy resulted in a limited recovery of BMD. Therefore, early hormone replacement therapy is mandatory for young amenorrheic women to minimize bone loss.