Oral contraceptive use and bone.

Sex hormones play a key role in bone homeostasis, and oral contraceptive (OC) use may affect bone mass in women. However, the nature of the association between OC use and bone remains controversial. This paper critically reviews studies on OC use and bone published between January 2009 and August 2010. Studies of OC use and bone mass mainly focus on adolescents or young adults and showed mixed results. Weak evidence suggests that OC use has no effect or a beneficial effect on bone mass, except in women commencing OCs shortly after menarche, and a consistently negative effect on bone turnover markers. A limited number of studies have examined the effect of ultra-low-dose OC (20 μg ethinyl estradiol) on bone mass in adolescents or young adults, and present conflicting results. The lack of randomized trials indicates that further high-quality prospective studies are required to investigate the effect of OC use on bone mass, particularly the optimal dose and timing of initiation of OC use in adolescents requiring contraception.