Ovarian follicles of a preovulatory size were encouraged to develop by extending the pill-free period of combine, triphasic oral contraceptive (OC) cycles. Despite recommencement of OC therapy, most follicles continued to grow and then respond to gonadotropin administration by both rupture and luteinization. It is concluded that follicles developing during OC cycles have the potential for ovulation, but this is of doubtful clinical significance for the vast majority of women.
PIP: To determine whether ovarian follicles developing during triphasic oral contraceptive cycles are capable of responding to a gonadotropin surge, follicles developing during the pill-free period were followed by ultrasound in 10 women. The subjects had been taking a triphasic formulation containing 30 mcg ethinyl estradiol (EE) with 50 mcg levonorgestrel for 6 days, 40 mcg EE with 75 mcg levonorgestrel for 5 days, and 30 mcg EE with 125 mcg levonorgestrel for 10 days. For the study, the pill-free period was extended until a 12 mm follicle was seen, and the woman began her pills. When the dominant follicle reached 18 mm, she received 5000 U hCG im. The 10 subjects took 7-16 days to develop a 12-mm follicle. Signs of ovulation judging by EE and progesterone levels and clinical signs and symptoms eventually were recorded in 8 of the 10 women. This study showed the wide individual variation in response in terms of follicle development, but does not suggest that failure of the pill is likely, because of other anti- fertility aspects of the triphasic pill.