Efficacy and Safety of Etonogestrel + 17β-Estradiol Vaginal Ring in Women at Risk for Pregnancy (MK-8342B-061)

Inclusion Criteria: * Premenopausal female at risk for pregnancy and seeking contraception. * Willing to use a hormonal contraceptive vaginal ring for up to 13 treatment cycles, and not intending to use any other form of contraception. * Body mass index (BMI) of ≥18 and \<38 kg/m2. * Willing to adhere to use of vaginal ring and all required trial procedures. Exclusion Criteria: * Cardiovascular risks and disorders, including history of venous thromboembolic \[VTE\] events, arterial thrombotic or thromboembolic \[ATE\] events, transient ischemic attack, angina pectoris, or claudication; at higher risk of VTE events due to recent prolonged immobilization, plans for surgery requiring prolonged immobilization, or a hereditary or acquired predisposition or elevated risk for venous or arterial thrombosis; currently smoking or uses tobacco/nicotine containing products and is ≥35 years of age; uncontrolled or severe hypertension; history of severe dyslipoproteinemia; \<35 years of age with a history of migraine with aura or focal neurological symptoms or ≥35 years of age with a history of migraines with or without aura or focal neurologic symptoms; diabetes mellitus with end-organ involvement or \>20 years duration; multiple cardiovascular risk factors such as older age, obesity, inadequately controlled hypertension, use of tobacco/ nicotine products, or inadequately controlled diabetes. * Gastrointestinal disorders, including history of pancreatitis associated with severe hypertriglyceridemia; clinically significant liver disease, including active viral hepatitis or cirrhosis. * Other medical disorders, including history of malignancy ≤5 years prior to signing informed consent except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer; any disease that may worsen under hormonal treatment such as disturbances in bile flow, systemic lupus erythematosus, pemphigoid gestationis or idiopathic icterus during previous pregnancy, middle-ear deafness, Sydenham chorea, or porphyria; known allergy/sensitivity or contraindication to investigational product or its excipients; history of drug or alcohol abuse or dependence. * Recent, current, or suspected pregnancy; or has not had at least 2 menstrual cycles or has not completed two 28-day cycles of a hormonal contraceptive (pill, patch or ring) following a recent pregnancy; or is breastfeeding. * Gynecologic conditions: has gonorrhea, chlamydia, or trichomonas or symptomatic vaginitis/cervicitis; has abnormal cervical Pap test or positive high-risk human papillomavirus (HPV) test at screening or documented within 3 years of screening; currently using an intrauterine device/ intrauterine system (IUD/ IUS) or contraceptive implant; within past 6 months has had undiagnosed (unexplained) abnormal vaginal bleeding or any abnormal bleeding expected to recur during trial; has stage 4 pelvic organ prolapse (1 cm beyond introitus) or lesser degrees of prolapse with history of difficulty retaining tampons, vaginal rings, or other products within vagina. * Has used investigational drug and/or participated in other clinical trial within past 8 weeks.