METHODS: The medical notes of 209 IVF cycles receiving GnRH agonist and hCG as ovulation trigger over 18 months were reviewed in this retrospective study. The number and quality of mature oocytes, the number and quality of embryos, pregnancy rates, and outcomes were compared using Independent T-test or One-way ANOVA for normal distribution. The Mann-Whitney test or Kruskal-Wallis test was used for not normally distributed. p<0.05 was considered statistically significant.

RESULTS: The cycle outcomes of 107 GnRH agonist-trigger and 102 hCG-trigger were compared. The MII oocytes retrieved and 2PN count was significantly higher in the GnRH agonist trigger group (p<0.001). Clinical pregnancy rate and ongoing pregnancy were higher in the GnRH agonist trigger group but were not statistically significant. The GnRH agonist trigger group was associated with low OHSS than the hCG trigger group (n=2(1.9%) and n=12(11.8%) respectively, p=0.004).