Ovarian activity during regular oral contraceptive use.

The aim of this study was to assess whether during regular OC use ovarian activity might lead to ovulation, as assessed by ultrasound (US) evaluation of follicular growth and blood levels of 17-beta-estradiol and progesterone. A total of 51 healthy women with normal menstrual cycles (28 +/- 3 days) and no gynecological symptoms were recruited. A total of 22 patients were given a triphasic OC pill containing 35 mg ethinyl estradiol (EE) and 50 mg desogestrel (DSG) in the first seven tablets; 30 mg EE and 100 mg DSG in tablets 8 to 14, and 30 mg EE and 150 mg DSG in tablets 15 to 21; 29 patients received one of two OC pills, both containing 20 mg EE plus 150 mg DSG (15 patients) or 75 mg of gestodene (14 patients). A total of 86 cycles were monitored: 51 during the 3rd-4th cycle and 35 during the 6th-8th cycle of OC treatment. Follicular-like structures were observed in nine patients. The frequency of follicular-like structures was similar during the 3rd-4th cycle (9%) and during the 6th-8th cycle (11%). There was no relationship between follicular growth and blood levels of E2 and progesterone, which always appeared suppressed. In conclusion, the results of this study suggest that during OC use (even with low dose of ethinyl estradiol), a little ovarian activity may be present without ovulation.