Contraception
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
A comparative study of two contraceptive vaginal rings releasing norethindrone acetate and differing doses of ethinyl estradiol.
Two combined contraceptive vaginal rings (CVR) each releasing approximately 1 mg norethindrone acetate (NET-Ac) and either 20 micrograms or 15 micrograms ethinyl estradiol over 24 h were tested at three clinic sites in Los Angeles, San Francisco, and Sydney. A total of 61 women were enrolled to use the ring on a schedule of 3 weeks in/1 week out for four treatment cycles. Serum estradiol, progesterone, norethindrone (NET), and ethinyl estradiol (EE) levels were assayed twice weekly in all four treatment cycles. ⋯ Side effects were infrequent and similar to those reported with other steroidal contraceptive methods. Three women complained of vaginal discharge, one with accompanying itch and one with a vaginal Candida infection in cycle 1. Overall, both of these EE/NET-Ac rings performed well, with only minor and mainly nonsignificant differences in effect on serum EE, NET, E2, and progesterone levels and lipids, and on vaginal bleeding patterns.