What is NuvaRing®? NuvaRing® is a soft plastic ring which is inserted by the woman into the vagina. Once inserted the ring slowly releases low doses of two hormones, oestrogen and a progestogen, into the bloodstream. These hormones are similar to those naturally produced by the female body and the same as those used in the combined oral contraceptive pill. How does NuvaRing® work? It prevents ovulation (egg release from the ovary) It thickens mucus in the cervix so sperm cannot enter the uterus (womb) It changes the lining of the uterus, making it unsuitable for pregnancy