OVARIAN-FUNCTION DURING LOW-DOSE ORAL-CONTRACEPTIVE USE

Lowering the total steroid dose in modern oral contraceptives (OCs) ha s 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 d uring use of two low-dose OCs, 65 volunteers were randomized to receiv e either 20 mu g ethinylestradiol (EE) + 150 mu g desogestrel (group A ) or 35 mu g EE + 250 mu g norgestimate (group B) for a 2-month study period. At baseline, 39% of women in group A and 31% in group B exhibi ted at least one follicle <35 mm in diameter. By the end of the second treatment cycle, the frequency of these follicles had decreased to 14 % in each group. Only one subject in the higher estrogen group develop ed an ovarian cyst >35 mm. One subject in each group demonstrated horm one levels characteristic of ovulation; no pregnancy occurred in eithe r group. The 20 mu g EE preparation was not found to lead more often t o ovarian follicles or cysts when compared with a 35 mu g EE preparati on, possibly because of the type and dose of the progestogen used.