Mature and immature oocytes in large and medium follicles after clomiphene citrate and human menopausal gonadotropin stimulation without human chorionic gonadotropin.

After ovarian stimulation with clomiphene citrate combined with human menopausal gonadotropin, 24 large (greater than 16 mm) and 16 medium (7 to 15 mm) human follicles were classified according to plasmatic estradiol (E2), luteinizing hormone (LH), and histology of the follicle and oocytes (in thin sections). An asynchronism of several hours between the stage of development of the largest and large cohort follicles is observed; overripeness of oocyte cumulus complex (OCC) is revealed. An asynchronous response to gonadotropins in granulosa and cumulus is also seen in the cohort of medium follicles of the same ovary, but not resumption of nuclear maturation of the oocyte. The efficiency of these oocytes after fertilization is discussed.