The aim of this study was to compare clinical and laboratory outcomes between GnRHa, dual and HCG triggers in altruistic oocyte donation cycles. Normal or high responders were given either gonadotropin releasing hormone agonist (GnRHa) or a dual trigger of GnRHa and a low dose of human chorionic gonadotropin (HCG). Low responders were given HCG trigger. In 333 cycles, 232 (69.7%) received GnRHa trigger, 59 (17.7%) received dual trigger and 42 (12.6%) had HCG trigger. The total number of mature oocytes retrieved and cryopreserved were significantly higher in the GnRHa and dual trigger groups, compared to the HCG group (p < 0.001). However, the ovarian hyperstimulation syndrome (OHSS) rate was significantly higher in the dual trigger group (n = 5 (8.5%)), compared to the GnRH agonist (n = 1 (0.4%)) and HCG groups (n = 0 (0%)) (p = 0.001). GnRHa trigger maximises mature oocyte yields in oocyte donors suspected of normal and high response but offers a significant reduction in OHSS risk compared to dual trigger. As such, dual trigger should not be used in oocyte donation. HCG trigger can also be used with a very low risk of OHSS at low risk of OHSS in carefully selected donors where GnRHa is unlikely to be effective.
Keywords: Cryopreservation; In-vitro fertilisation; Oocyte donation; Ovarian Hyperstimulation Syndrome; Ovulation trigger.