This study was performed on an out-patient basis where all the subjects received one treatment cycle of pituitary desensibilization with GnRH agonist (GnRH-a). The desensibilization was commenced at the middle of the luteinic phase (long protocol). Once the decrease in pituitary activity was confirmed using estradiol (E2) < 50 pg/ml (180 pmol/l) as criteria, COS was initiated with an r-hFSH dosage of 300-450 IU administered subcutaneously (sc). On Day 6 of stimulation (S6), subjects were randomly assigned to an additional treatment with r-hLH with a fixed dosage of 150 IU or were continued to be treated with r-hFSH alone. The first dose of r-hLH was administered late in the evening on the day the randomisation was carried out (S6).