The clinical research to date on the effects of 3 types of hormonal contraceptives, i.e. depot medroxyprogesterone acetate ('Depo-Provera'), levonorgestrel subdermal implants ('Norplant'), and oral contraceptives, on bone mineral density in premenopausal women is reviewed. The large variance in results across studies for each method is in part due to differences in research design, techniques for measuring bone mineral density, age of the study participants and type of oral contraceptive preparation. However, the balance of the evidence leans toward a positive effect of oral contraceptives on bone mineral density in women of all age. On the other hand, few observations have yet been published on the effects of the new progestin oral contraceptives on bone mineral density. The few extant data suggest a positive impact of levonorgestrel subdermal implants on bone mineral density in women of all ages. Although the findings are preliminary, it appears that depot medroxyprogesterone acetate may exert a negative effect on bone mineral density. More specifically, caution should be exercised in prescribing long term depot medroxyprogesterone acetate (e.g. >5 years) especially in young adolescents (e.g. <16 years old) who may not have yet reached peak bone mass.
