The combined contraceptive vaginal ring and bone mineral density in healthy pre-menopausal women.

Background: Hormonal contraceptives have been associated with various effects on the bone mineral density (BMD) of pre-menopausal women. The aim of this study was to assess the effects of a vaginal contraceptive ring on BMD in pre-menopausal women and compare them with those of non-hormonal contraceptive use.

Methods: This open-label, multicentre study used dual-energy X-ray absorptiometry to measure BMD in the lumbar spine (L(2)-L(4)) and femoral neck regions. Subjects were assigned 3:1 to receive a contraceptive ring (n = 105) or a non-hormonal contraceptive control (n = 39) and were assessed after 13 and 26 cycles of contraceptive ring treatment or 12 and 24 months of control treatment.

Results: No change from baseline in BMD (Z-scores) was seen in contraceptive ring users (n = 73) at either time-point. In the control group (n = 30), BMD increased slightly from baseline resulting in significant differences (P < 0.0001) between the two groups at cycle 26/month 24. These differences are not clinically relevant, although some degree of acquisition of peak bone mass might have been prevented in the contraceptive ring group. The contraceptive ring was generally well tolerated; a higher incidence of treatment-related adverse events was observed in the contraceptive ring group compared with the non-hormonal contraceptive control group.

Conclusions: In healthy pre-menopausal women, 2 years of contraceptive ring use produced no changes in BMD.