The role of the birth control ring is to prevent unwanted pregnancy. The role of the birth control ring is to interfere with the union of sperm and egg, which means that the substances contained can indirectly kill sperm, thus preventing women from becoming pregnant. Second, to prevent women from infection, especially married women have sex, the vagina is more likely to suffer from external bacterial infection, to women with birth control ring can be very good control of women to prevent accidental infection, especially during sex. Third, the birth control ring can prolong women’s menstrual period, that is, the birth control ring can make women’s menopause delayed 3-5 years, because the birth control ring can change women’s endocrine, to prevent premature ovarian failure. Fourthly, some birth control rings have therapeutic effects in addition to contraception, such as Manuel, which is a birth control ring containing levonorgestrel and can effectively treat patients with excessive menstruation, dysmenorrhea, abnormal endometrial hyperplasia and endometriosis.