ABSTRACT
Regarding the endocrine characteristics of stimulated cycles, plasma measurement of steroids is currently performed because it directly refl ects the biological effect of gonadotropins on the ovary. Steroids are involved in the implantation process but may also play a paracrine or even an autocrine role on the cumulusoocyte unit. Estradiol (E2) and progesterone measurements are currently done to adjust the daily dose of exogenous gonadotropins, whereas the determination of androgen production has been only performed in some clinical trials.
