[The hormonal micromilieu and oocyte status in the stimulated in vitro fertilization cycle]

FSH, LH, PRL, estradiol-17 beta and progesterone were determined in 651 follicular fluids of 173 patients treated by ovarian stimulation for IVF. The stimulation was performed according to 5 different schemes: clomiphene/HCG, HMG (Pergonal)/HCG, HPG (Anthrogon)/HCG, clomiphene/HPG/HCG, Folistiman (heterologeous pituitary gonadotropin)/HCG. The mean levels of hormones of all follicles of each stimulation scheme were determined and differences between the groups were estimated by Student's t-test and the x-square-test. Additionally, in a hierarchy of follicles made depending on the follicular fluid volume the hormonal levels were compared between different rank numbers of one stimulation group and between different groups of stimulation. The maturation of oocytes judged by a maturation index and their ability for cleavage in culture after insemination was investigated in relation to the hormonal content of the follicular fluid. Stimulation by gonadotropins (Pergonal, Anthrogon, Folistiman) led to an decreased mean level of follicular steroids. This was related to an increased part of follicles poor in steroids after stimulation by gonadotropins. Within the follicular population follicles stimulated by clomiphene/HCG had a reduction of the levels of estradiol in higher rank numbers, but there were no clear evidences for such a reduction in the other stimulated groups. In all stimulation groups a significant reduction of progesterone levels was observed in higher rank numbers of follicles. Oocytes with a high maturation index mainly derived from follicles rich in progesterone. After insemination, development of oocytes in culture was compatible even with very high or low levels of hormones. There was no relation of the levels in FSH and LH to cumulus expansion and levels of estradiol of the follicular fluid. There was also no clear correlation between the levels of prolactin in follicular fluid and the cleavage rate.