Oocyte donors and women electing fertility preservation are at increased risk of developing ovarian hyperstimulation syndrome (OHSS). Different strategies are used to lower the risk, such as decreasing the hCG dose or using gonadotropin releasing hormone agonist (GnRHa) as an alternative to hCG. However, trigger failures can occur when using GnRHa alone. Alternatively, adding low dose hCG to GnRHa may allow a decreased incidence of OHSS while avoiding trigger failures. Retrospective chart review of oocyte donation and fertility preservation cycles using GnRHa and long luteal protocols between 01/01/10 and 02/02/14. 364 total IVF/ICSI cycles were analyzed. Oocyte maturity was induced by either GnRHa, hCG, or GnRHa plus 1500IU hCG. Correlation of post trigger LH and hCG levels to maturation parameters were assessed in 199 cycles. Spearman’s correlation assessed correlation between post-GnRHa trigger LH with proportion of total and mature oocytes retrieved as well as fertilization. 1-way ANOVA was used to compare oocyte maturation between each different trigger. All 3 failed triggers were with GnRHa only. No OHSS developed after GnRHa plus 1500IU hCG. No difference was noted in proportion of metaphase II (MII) oocytes to mature size follicles measured on day trigger, MII oocytes to total oocytes retrieved, or the number of 2 pronuclei (2PN) to total oocytes retrieved between those that were triggered with either hCG, GnRHa, or GnRHa plus 1500IU hCG. No difference was appreciated in the same proportions when comparing hCG trigger dose of 10000, 5000, and 3300 IU. There was a significant negative correlation of the LH level post-GnRHa plus hCG trigger to the proportion of 2PN and oocytes retrieved (p = 0.046) but not with GnRHa alone. No other significant correlations were found between parameters of oocyte maturity and post trigger LH.Tabled 1Characteristics based on triggerVariableshCG onlyGnRHa onlyGnRHa + hCGP valueAge24.9±2.826.7±4.226.3±4.10.079AFC24.6±9.928.9±9.829.1±9.50.004Follicles >13mm18.7±5.726.1±7.924.2±6.4<0.001# MII19.9±8.825.8±12.024.8±12.50.063Maturity(MII/ follicles >13mm)1.07±0.391.03±0.351.02±0.370.831Fertilization (2PN/total oocytes retrieved)0.67±0.160.63±0.160.65±0.190.453Mean ± STD Open table in a new tab Mean ± STD Adding low dose hCG to a GnRHa trigger may allow a decrease in OHSS incidence, and appears to not compromise oocyte maturity while avoiding failed oocyte maturation. Using this alternative form of trigger appears to be most optimal for donor and fertility preservation cycles that are at very high risk of developing OHSS.