The contraceptive ring ( also called NuvaRing) is a method of birth control that contains artificial forms of the hormones that are normally produced in the ovaries of women: estrogen and progestin. These prevent the ovary from releasing an egg during her menstrual cycle; the progestin, also helps to prevent sperm from entering the uterus, causing the mucus that exists in the cervix becomes thick. It is a flexible ring about five inches in diameter to the same woman placed inside the vagina. It is a monthly contraceptive: it must remain in the vagina for three weeks;after, retires for a week. However, keep in mind that it can produce side effects such as nausea, vaginitis or breakthrough bleeding.