The vaginal ring is a flexible ring about 2 inches in diameter that is inserted into the vagina. It releases progestin and estrogen into the body to avoid pregnancy. The woman inserts it herself and it stays in the vagina for 3 weeks. Then, she takes it out for one week to have her period. Like other hormone methods, a prescription from a doctor is required.Update Date: 3/25/2008 Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz, Kelli A. Stacy, ELS. Previously reviewed by Rachel A. Lewis, MD, FAAP, Columbia University Pediatric Faculty Practice, New York, NY. Review provided by VeriMed Healthcare Network (5/6/2007).