Additional Study Information: You may be eligible if you are younger than 51 years old, have regular monthly periods with moderate to severe cramping, and are willing to try a NEW hormonal vaginal ring. The ring contains estrogen and progestin which are hormones found in some types of birth control pills, patches and rings.Participation in the study will consist of 6 study visits and 2 telephone contacts over 8 months. The visits will vary but mostly consist of physical check-ups, urine pregnancy testing, blood pressure checks, with occasional gynecological exams and blood draws. You will also be required to record information every day in a small electronic diary. Adolescents and women who are not sexually active may be eligible to participate.Compensation: up to $1000 for time and travel