Impact of combined and progestogen-only contraceptives on bone mineral density.

Sex steroids are major determinants of bone mass, and hormonal contraceptives may affect bone mineral density (BMD) in women. Combination contraceptives probably have no impact on BMD, except perhaps when started within 3 years after the menarche. Progestogen-only contraceptives are being increasingly used. Injectable medroxyprogesterone acetate, a potent inhibitor of gonadotropin release, can induce bone loss, most notably in young women. Other progestogens are used in lower doses that have weaker antigonadotropin effects. Levonorgestrel and etonorgestrel implants have unclear effects on BMD but are probably safe. The impact of high- and low-dose oral progestogens on BMD has not been investigated, although no adverse effects would be expected.