Abstract
OBJECTIVES: To explore the effects of exogenous trigger (hCG/GnRHa) versus endogenous LH surge in natural cycle IVF/ICSI (NC-IVF/ICSI) for patients with diminished ovarian reserve (DOR). METHODS: A retrospective analysis was conducted on 1,118 NC-IVF/ICSI cycles from two reproductive centers between 2013 and 2024. Propensity score matching (PSM) and multivariate logistic regression were used to adjust for confounding factors. The trigger-day hormone threshold was determined using receiver operating characteristic (ROC) curve analysis. Outcome measures included oocyte retrieval rate, 2PN fertilization rate, clinical available embryo rate, high-quality embryo rate, fresh cycle clinical pregnancy rate (CPR), and live birth rate (LBR). RESULTS: After adjusting for confounders via PSM and logistic regression, the exogenous trigger group demonstrated significantly better outcomes across all the evaluated parameters (oocyte retrieval rate, 2PN fertilization rate, transferable embryo rate, high-quality embryo rate, fresh cycle CPR, and LBR) than the endogenous LH surge group (P<0.05). Age-stratified analysis revealed that for the entire cohort, exogenous triggering significantly increased the number of transferable embryos and high-quality embryos (P<0.001). In the 35-39 years old subgroup, exogenous triggering showed significant advantages in oocyte yield, high-quality embryo rate, CPR, and LBR (P<0.05) and resulted in the most pronounced improvement in LBR (OR=6.25, 95% CI: 1.34-29.23). ROC analysis established a decision-day LH threshold of 19.055 mIU/mL (AUC=0.945, specificity=93.3%) for precise stratification of the clinical pathways. CONCLUSIONS: For DOR patients undergoing NC-IVF/ICSI, exogenous triggering comprehensively improves the treatment outcomes, particularly providing significant live birth benefits for women aged 35-40 years. An individualized protocol incorporating the LH threshold (19.055 mIU/mL) effectively enhances embryonic developmental potential and live birth rates.