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Updated: Jun 5, 2026

Rodent Estrous Cycle Monitoring Utilizing Vaginal Lavage: No Such Thing As a Normal Cycle
Published on: August 30, 2021
Vaginal ring contraception
Jennifer Kerns1, Philip Darney
1Department of Obstetrics, Gynecology and Reproductive Sciences, Bixby Center for Global Reproductive Health, University of California, San Francisco, San Francisco, CA 94110, USA. kernsjl@obgyn.ucsf.edu
Abstract:
The contraceptive vaginal ring is a relatively new combined hormonal contraceptive method. Ethinyl estradiol and etonogestrel are rapidly absorbed through the vaginal epithelium and result in a steady serum concentration. Studies have demonstrated that the efficacy and safety of the ring are equivalent to oral contraceptives (OCs). Patients report being highly satisfied with the vaginal ring and report fewer systemic side effects than do OC users. The ring provides effective cycle control as well as symptom relief for women with menorrhagia, dysmenorrhea and polycystic ovarian syndrome. A new combined contraceptive ring containing Nestorone and ethinyl estradiol is currently being investigated in a Phase 3 trial. A progesterone-releasing vaginal ring appropriate for lactating women is available in Chile and Peru. Recent studies have demonstrated that vaginal rings can also be effective means of delivering antiretroviral drugs that provide protection from HIV.
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