Abstract
PURPOSE: To determine the optimal hCG dose in a dual hCG/GnRH agonist trigger for comparable pregnancy outcomes to hCG, while maintaining low OHSS rates in good-prognosis patients. SUBJECTS: This retrospective cohort study included patients aged 18-41 years undergoing IVF or IVF/ICSI with fresh embryo transfer from 2013 to 2024. Patients received either hCG-only (5,000-10,000 IU hCG/250-500 mcg Ovidrel) or dual trigger (1,500-2,000 IU hCG + 2 mg GnRH agonist). RESULTS: A total of 2641 cycles were analyzed (1,939 hCG-only, 616 1,500 IU hCG dual trigger, and 86 2,000 IU hCG dual trigger). The 2,000 IU hCG dual trigger group yielded more mature oocytes (16.0 vs. 11.6, aRR 1.29), fertilized embryos (12.9 vs. 8.8, aRR 1.43), and blastocysts (8.0 vs. 4.9, aRR 1.55) than hCG-only. Implantation rates were higher with 2,000 IU hCG dual trigger than hCG-only (50.0% vs. 32.0%, RR 1.56), with a dose-dependent improvement within the dual trigger groups (50.0% at 2,000 IU vs. 36.4% at 1,500 IU, RR 1.37). Ongoing pregnancy rates were similar between 2,000 IU hCG dual trigger and hCG-only (46.8% vs. 39.5%, aRR 1.12), but lower with 1,500 IU hCG dual trigger (46.8% vs. 37.6%, aRR 1.37). OHSS rates were low across all groups. CONCLUSION: 2,000 IU hCG appears to be the optimal dose in a dual hCG/GnRH agonist trigger, resulting in similar pregnancy outcomes to an hCG trigger and low rates of OHSS among good-responder patients. Ongoing pregnancy rates were significantly lower with hCG doses under 2,000 IU in the dual trigger protocol.