PIP: In order to determine whether the loss in bone density seen in users of depot medroxyprogesterone acetate is reversible, a comparative study was undertaken in three groups of women. Group 1 consisted of 14 women who had used the contraceptive for at least 3 years and then discontinued use. Group 2 was 22 longterm users, and Group 3 contained 18 women who had never used the drug and served as controls. Estrogen production resumed in all of the Group 1 women after discontinuation. Two bone density measurements were taken twice in each woman. At first measurement, lumbar spine density was an average of 9% lower in Groups 1 and 2 than in controls. At the second measurement, however, lumbar spine density had significantly increased in Group 1 while it remained the same for the other groups. No significant changes in femoral neck density were observed. Additional measurements in 8 women from Group 1 taken 2 years after discontinuation revealed a further significant increase in lumbar spine bone density. Thus, it was concluded that bone density loss is reversible, even in cases where women experience a significant weight loss after discontinuation.