Ovarian activity and bleeding patterns during extended continuous use of a combined contraceptive vaginal ring

A combined contraceptive vaginal ring with a mean release rate of 0.015 mg of ethinyloestradiol and 0.120 mg of 3-ketodesogestrel per day was used by female volunteers, for either 28, 42, 56 or 84 days. Contraceptive efficacy was assessed by pelvic ultrasound scanning, endocrine monitoring and cervical mucus assessment. Menstrual diary cards were analysed to assess the effect on cycle control. Ovulation inhibition was seen in all treatment groups. Following removal of the ring, a return to an ovulatory cycle was observed in all volunteers. With extension of the treatment cycle beyond the recommended 21 days, there is an increase in the occurrence of bleeding and spotting episodes. This can be compared to patterns obtained during continuous use of combined oral contraceptives.