Efficacy and Safety of Etonogestrel + 17β-Estradiol Vaginal Ring (MK-8342B) in Women With Primary Dysmenorrhea (With Optional Extension) (MK-8342B-059)

The purpose of this study is to assess the etonogestrel (ENG) + 17β-estradiol (E2) vaginal ring's efficacy compared to a placebo vaginal ring in the treatment of dysmenorrhea at Treatment Cycle 2. In addition, this study will assess the safety and tolerability of the ENG-E2 vaginal rings. Primary hypothesis: Relative to the placebo ring, the ENG-E2 vaginal ring results in a greater proportion of participants with a ≥3 point reduction in peak pelvic pain score and no increase in the number of rescue pain relief (ibuprofen) tablets taken at Treatment Cycle 2 as compared to baseline.