Oral contraceptive use may protect against low bone mass. Henry Ford Hospital Osteoporosis Cooperative Research Group

Effects on bone mineral density of a monophasic combined oral contraceptive containing nomegestrol acetate/17β‐estradiol in comparison to levonorgestrel/ethinylestradiol

“…The effect of oral contraceptives on BMD is an area of active investigation, with some studies reporting increased BMD in users of EE‐containing COCs (4–7,10,24), some reporting no change (8,9,11) and some reporting decreased BMD (3,11,12). One strength of the present study was that it was a prospective randomized interventional trial.…”

Effect of oral contraceptives and hormone replacement therapy on bone mineral density in premenopausal and perimenopausal women: a systematic review

“…Ten (three cohort, [16][17][18] seven cross sectional [19][20][21][22][23][24][25] ) showed a positive effect, 29 (four RCTs, [26][27][28][29] nine cohort, 30-38 15 cross sectional, [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] one case series 54 ) showed no effect, and seven (four cohort, [55][56][57][58] three cross sectional [59][60][61] ) showed a negative effect. All of the RCTs showed no effect on BMD, as measured by either dual energy x ray absorptiometry (DXA) 26 27 29 or quantitative computed tomography.…”

Hormonal contraception: recent advances and controversies

“…Studies in postmenopausal women who have previously used OCs have revealed improved bone density that correlates with years of use (81). Reduced fracture risks that correlate with the use of high-dose formulations and use after the age of 40 also have been demonstrated in postmenopausal women (82).…”