Background: Highly purified menotrophin (HP-hMG) has been associated with fewer oocytes retrieved and a higher proportion of top-quality embryos compared with recombinant FSH (rFSH).
Methods: A randomized, assessor-blind, multinational trial in 731 women undergoing IVF after stimulation with HP-hMG (MENOPUR) (n = 363) or rFSH (GONAL-F) (n = 368) following a long GnRH agonist protocol was conducted. Blood was collected before, during and after stimulation. Fluid was collected from follicles > or =17 mm.
Results: Serum androstenedione, total testosterone and free androgen index (FAI) were higher (P < 0.001) with HP-hMG than with rFSH after starting stimulation. At the end of stimulation, serum estradiol was higher (P = 0.031) with HP-hMG, whereas progesterone was higher (P < 0.001) with rFSH, even after adjusting for ovarian response. Serum LH was not different between treatments. Mean mid- and end-follicular hCG levels in the HP-hMG group were 2.5 and 2.9 IU/l, respectively. Follicular fluid levels of FSH, LH, hCG, androstenedione, testosterone, FAI and estradiol and ratios of estradiol:androstenedione, estradiol:total testosterone and estradiol:progesterone were higher (P < 0.001) with HP-hMG, whereas progesterone was higher (P < 0.001) with rFSH.
Conclusion: Major differences in serum and follicular fluid endocrine profile exist after stimulation with HP-hMG or rFSH. Exogenous LH activity induces a differential endocrine environment influencing oocyte quantity and quality, which may be of relevance for clinical outcome.