Regarding residual confounding: although we balanced key baseline characteristics (e.g., female age, infertility type) via strict inclusion/exclusion criteria (Table 1), critical confounders could not be fully addressed—including female age-related declines in oocyte quality (subtle variations in oocyte competence may have influenced outcomes), diminished ovarian reserve (exacerbated by 45.7% AMH data missing rate), and potential inconsistencies in ovulation monitoring (minor variations in hCG injection timing or monitoring frequency in early records). This evidence concerns the gene AMH and Infertility.