Vaginal Administration

The CVR avoids oral route, sustained release
CVR dosing lower=same ovarian suppression but half the systemic estrogen (EE2 50% bioavailable)
Failure 0.6-1.2%…user problem still
Ring free week, like patch or pill free week trigger withdrawal bleeding and the period
Roumen et al. Efficacy, tolerability, and acceptability of a novel contraceptive vaginal ring releasing etonorgestrel and ethinyl estradiol. Human Reproduction 2001;16:469-475.

The CVR avoids oral route, sustained release