Endocrine effects of hCG supplementation to recombinant FSH throughout controlled ovarian stimulation for IVF: a dose response study

OBJECTIVE: To analyse the endocrine response in relation to the ?-4 and ?-5 pathway of ovarian steroidogenesis after different doses of hCG supplementation to recombinant FSH from Day 1 of controlled ovarian stimulation for IVF. DESIGN: A randomised dose-response pilot study. PATIENTS: A total of 62 IVF patients aged 25-37 years with regular cycles, and FSH RESULTS: A significant hCG dose-dependent incremental increase was found for progesterone (49%-160%), 17-OH progesterone (223%- 614%), androstenedione (91%-340%), and testosterone (95%-338%) from Dose 0 to Dose 150, respectively. DHEA showed minor changes during stimulation and no differences between the groups. The highest estradiol concentrations were observed in Dose 100 and Dose 150. SHBG increased similarly in all groups at the end of stimulation. No difference was observed for AMH concentration between the groups, but a 50% decline from the start to the end of the stimulation was found. CONCLUSION: Supplementation with hCG resulted in a clear dose-related response for androgens, progesterone and 17-OH-progesterone. Estradiol concentration reached maximum levels with an hCG dose of 100 IU/day, suggesting saturation of aromatase function. No difference between the groups was observed for DHEA, supporting that the stimulatory effects of hCG doses on androgens and estrogen production were mainly induced via the ?-5 pathway. SHBG, being a biomarker of estrogen/androgen balance, was not changed by increasing hCG.