Participants eligible for this trial were oocyte donors 18-37 years of age, who had undergone controlled ovarian hyperstimulation in the long GnRH agonist protocol or the multiple-dose or single-dose GnRH antagonist protocols, had received hCG (10,000 IU urinary hCG or 250 μg recombinant hCG) for triggering of final follicular maturation and had undergone oocyte retrieval. Participants had given signed informed consent, were generally healthy and with a body mass index (BMI) of 18.5-29 kg/m2.