Clinical performances and endocrine profiles with contraceptive vaginal rings containing d-norgestrel

Abstract

A clinical study was undertaken with contraceptive vaginal rings (CVRs) of a 3-layered “shell” design impregnated with d-norgestrel. The rings were studied in 10 normally menstruating women for 6 treatment cycles on a “3-week in, 1-week out” schedule. No adverse local effects occurred and patient and consort acceptance was good. Ovulation occurred in only 2 of the 60 treatment cycles (3.3%). Breakthrough bleeding and spotting occurred in 33.3% of cycles and 6.7% of treatment days, and failure of withdrawal bleeding in 3 (5.0%) cycles. Mean daily d-norgestrel loss was calculated to be 279.7 μg/day. Serum d-norgestrel levels were higher in the first cycle of use (mean 2.44 ± 0.55 S.D. ng/ml), than in subsequent cycles (mean 1.98 ± 45 ng/ml in the second cycle to 1.51 ± 0.40 ng/ml in the sixth cycle). For each subject serum d-norgestrel levels showed little fluctuation in each treatment cycle. Estradiol levels were consistently low, usually less than 50 pg/ml. Serum d-norgestrel levels could not be correlated with the incidence of either breakthrough bleeding or ovulation. Although the incidence of breakthrough bleeding, failure of withdrawal bleeding, and ovulation was less than previously reported with other designs of norgestrel CVRs, the incidence of each of these events remains too high to have a clinically acceptable contraceptive method.