OBJECTIVETo compare the outcomes achieved by GnRH-antagonist and GnRH-agonist in IVF-ET for patients with poor ovarian responses, and to find out a better protocol for ovulation stimulation.

METHODS(1) Patients with poor ovarian responses were assigned to an experimental (n = 63) and a control group (n = 58), treated respectively with GnRH-Ant and oral contraceptive plus micro-dose GnRH-a (OC + GnRH-a), and comparisons were made of the medication doses, laboratory results and pregnancy outcomes between the two groups. (2) Twenty of the patients were treated first with GnRH-Ant and then with OC + GnRH-a, and the same comparisons were made between the two protocols.

RESULTSBetween the experimental and the control groups, there were no significant differences in the dose of Gn and number of retrieved oocytes and transplanted embryos (P > 0.05), nor in the pregnancy rate of transplantation cycles (37.29% vs 35.29%). The cycle cancellation rate was lower in the experimental than in the control group (6.35% vs 12.07%), with no statistical difference (P > 0.05). The cycle duration was significantly different between the two groups ([9.65 +/- 1.60] d vs [19.05 +/- 3.94] d) (P < 0.05). As for the comparison of GnRH-Ant with GnRH-a, no significant differences were observed in the dose of Gn and the numbers of retrieved oocytes and transplanted embryos (P > 0.05). GnRH-Ant achieved a higher pregnancy rate of transplantation cycles but a significantly lower cancellation rate than GnRH-a (38.09% vs 17.64% and 0% vs 15%) (P > 0.05 and P < 0.01), respectively. The cycle duration of the former was statistically shorter than that of the latter ([9.91 +/- 2.49] d vs [27.74 +/- 25.39] d) (P < 0.05).

CONCLUSIONCompared with micro-dose GnRH-a, GnRH-Ant can shorten the cycle duration and reduce the cancellation rate in IVF-ET for patients with poor response. And for those who have failed to respond to GnRH-a, GnRH-Ant may be tried in another attempt at IVF-ET.