Comparison between a GnRH antagonist and a GnRH agonist flare-up protocol in oocyte donors: a randomized clinical trial

BACKGROUND: Little information is available on the outcome of controlled ovarian hyperstimulation (COH) using GnRH antagonist in oocyte donation cycles especially in comparison with the short GnRH agonist protocol. This study was aimed at comparing the two stimulation protocols in oocyte donation (OD) cycles. METHODS: A total of 113 donors randomly received COH using either GnRH antagonist or GnRH agonist. The primary endpoint was the mean number of mature oocytes retrieved per started donor cycle. Secondary endpoints were the mean number of cumulus-oocyte-complexes (COCs) retrieved, the mean proportion of mature oocytes, pregnancy and implantation rates in recipients. RESULTS: Oocytes were distributed to 166 recipients. The mean number (+/- SD) of COC (11.6 +/- 5.8 versus 12.1 +/- 6.7), mature oocytes (8.4 +/- 4.4 versus 8.9 +/- 5.3) and the proportion of mature oocytes (70.8 versus 75.7%) retrieved per started donor cycle were similar in the antagonist and agonist groups, respectively. The implantation rate (26.1 versus 30.1%), clinical (40.2 versus 45.6%) and ongoing pregnancy rate per recipient cycle (32.2 versus 37.9%) were comparable in antagonist and agonist protocols, respectively. CONCLUSIONS: Similar mean number of mature oocytes and comparable pregnancy rates are achieved after OD in which donors received COH using GnRH antagonist or short GnRH agonist protocols.