Background: The optimal dose of human chorionic gonadotropin (hCG) supplementation during controlled ovarian stimulation (COS) remains controversial, particularly in women of advanced reproductive age. Objective: To compare the efficacy and safety of 150 IU versus 100 IU daily hCG supplementation from stimulation day 6 in women aged ≥ 35 years undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Methods: In this retrospective cohort study, we analyzed data from 438 patients aged ≥ 35 years undergoing IVF at a single center. Propensity score matching was performed at a 1:1 ratio, yielding 192 patients per group who received either 100 IU or 150 IU daily hCG supplementation from stimulation day 6 during GnRH antagonist cycles. Results: After propensity score matching, baseline characteristics were comparable between groups. The 150 IU group yielded significantly more total oocytes (9.23±6.60 vs 7.79±5.52, p<0.001). However, the number of mature oocytes (6.25±5.12 vs 5.66±4.58) and day 3 embryos (5.22±4.62 vs 4.80±3.96) did not differ significantly between groups. Total FSH dose was similar (2664.84±141.91 vs 2666.02±142.51 IU, p=0.936). Only one case of moderate ovarian hyperstimulation syndrome occurred in the 150 IU group. Conclusions: In women aged ≥ 35 years, while 150 IU daily hCG supplementation from stimulation day 6 safely increased total oocyte yield compared to 100 IU, it did not significantly improve mature oocyte numbers or embryo development.
