Follicular steroids in relation to oocyte development and human ovarian stimulation protocols

Oocytes of pre-ovulatory follicles were collected by laparoscopy for in-vitro fertilization in 118 women. Patients were treated either during the natural cycle, or after induction of ovulation with clomiphene citrate, or with human menopausal gonadotrophin (HMG), or clomiphene citrate combined with HMG. The oestrogens (oestrone + oestradiol) and total aromatizable androgens (androstenedione, testosterone and dehydroepiandrosterone and its sulphate) were assayed in follicular fluids using an enzymatic method. The levels of progesterone, 17 alpha OH-progesterone, thromboxane, and prostaglandins (PGE2 and PGF2 alpha) were determined by radioimmunoassay. The best follicular fluid indicator of oocyte fertilization in vitro was the A/E ratio, which was less than 1 when the oocyte was fertilized in vitro and led to a pregnancy. The lowest value for the A/E ratio was obtained with spontaneous ovulation protocols. Regardless of oocyte development, the progesterone level was always greater than 2000 ng/ml, and the PGE2/PGF2 alpha ratio was greater than 1 in all stimulated cycles. Our investigations show that a combination of clomiphene citrate and HMG provides the best stimulation, on the basis of follicular fluid analysis and the outcome of fertilized oocytes.