Purpose of review: This report critically reviews recent original research articles that pertain to bone mineral density in young adult women utilizing injectable depot medroxyprogesterone acetate or oral contraceptives.
Recent findings: Some evidence indicates that depot medroxyprogesterone acetate and ultra-low dose oral contraceptives (containing 20 microg ethinyl estradiol) may interfere with the large increases normally observed in adolescence; however, the same degree of bone loss (or lack of bone gain) associated with these drugs is not so impressive in young adult women who would typically be experiencing small changes in bone mass. Data obtained from young adult women show that low dose (30-40 microg ethinyl estradiol) oral contraceptives seem to be more protective of bone than ultra-low dose oral contraceptives. The few extant data suggest that there may be substantial increases in bone mass after discontinuation of depot medroxyprogesterone acetate; no information is available regarding the response of bone after discontinuation of oral contraceptives. As the clinical risk for fracture is usually several decades later, several exogenous factors such as diet and exercise may exert overriding influences on later bone health. Moreover, without contraception, the clinical outcome may be unwanted pregnancy and its potential impact on bone health.
Summary: Recent findings suggest that depot medroxyprogesterone acetate and ultra-low dose oral contraceptives may interfere with achieving optimal peak bone mass in very young women; however, there may be substantial recovery after cessation of these methods and overriding long-term influences on bone health imposed by a myriad of lifestyle factors.