INTRODUCTION: This prospective observational study evaluated the bleeding patterns of women using a vaginal ring releasing 120 microg of etonogestrel and 15 microg of ethinyl estradiol daily, over a continuous period of 84 days followed by 7 ring-free days. METHODS: The study enrolled 75 volunteers aged 18 to 37 years. Sixty-two (82.8%) recorded their menstrual cycles during 1 year. RESULTS: At the end of the study, 85.5% had adequate menstrual patterns (two to four bleeding episodes, none lasting 10 days or more, with a range of bleeding-free intervals not exceeding 17 days), 9.7% had infrequent bleeding, 1.6% reported prolonged bleeding episodes, 1.6% had frequent bleeding and 1.6% had irregular bleeding. CONCLUSION: Only 5 of the initial 75 patients discontinued the method due to bleeding. Among these 75 women, dissatisfaction with bleeding patterns was not a frequent reason given for discontinuation of the contraceptive vaginal ring.