Ovarian function during low-dose oral contraceptive use

Abstract Lowering the total steroid dose in modern oral contraceptives (OCs) has been connected with a higher incidence of ovarian follicle and cyst formation. To investigate the presence of ovarian follicles and cysts by means of vaginal ultrasonography and serum hormone determinations during use of two low-dose OCs, 65 volunteers were randomized to receive either 20 μg ethinylestradiol (EE) + 150 μg desogestrel (group A) or 35 μg EE + 250 μg norgestimate (group B) for a 2-month study period. At baseline, 39% of women in group A and 31% in group B exhibited at least one follicle 35 mm. One subject in each group demonstrated hormone levels characteristic of ovulation; no pregnancy occurred in either group. The 20 μg EE preparation was not found to lead more often to ovarian follicles or cysts when compared with a 35 μg EE preparation, possibly because of the type and dose of the progestogen used.