Intracervical release of levonorgestrel for contraception.

Twenty-one women used a levonorgestrel-releasing intracervical contraceptive device, which was designed to release 20 microgram/ay. The devices were inserted after cessation of menstrual bleeding. Patterns of bleeding and clinical performance wer evaluated and plasma concentrations of levonorgestrel, estradiol and progesterone in selected subjects were measured by radioimmunoassay. The results of the initial 90-day treatment are presented. Levonorgestrel was detected in peripheral plasma by 30 minutes after insertion of the device. Considerable variation of plasma levonorgestrel concentrations was observed between subjects, but within each subject, the plasma level of levonorgestrel was very stable with time. Of 24 cycles monitored by blood sampling, 19 were ovulatory. One subject did not ovulate at all. During the first 30-day period of treatment, frequent intermenstrual bleeding or spotting periods occurred. Two spontaneous expulsions occurred 9 and 22 days after insertion. Both of these subjects were nulligravidas. Side-effects were few and no pregnancies occurred during the study period.