Intravaginal contraception with the synthetic progestin, R2010.

Four women used polysiloxane vaginal rings of core design containing 50 mg of norgestrienone (17 alpha-ethynyl-17 beta-hydroxy-estra-4,9,11,trien-3-one). The treatment was given in three-week cycles, leaving one treatment-free week between the cycles. The patterns of bleeding were registered and plasma norgestrienone (R2010), estradiol, progesterone, and gonadotropins were determined. Altogether twelve cycles were studied. The patterns of bleeding were unsatisfactory; only one subject had regular bleedings, and two of these were preceded by a luteal phase. The mean plasma concentration of norgestrienone (R2010) produced by the rings was 0.9 ng/ml. Ovulation was observed in 25% of cycles studied. Some follicular activity was present in every subject as judged by estradiol peaks. Excluding LH peaks in subjects who ovulated, mild pituitary suppression was achieved by this treatment. The only side-effect complained of was acne in one subject. The ring was regarded as easy to use.