Supplementary Table S1-S3

Supplementary Table S1 provides detailed reasons for treatment discontinuation before completion of three embryo transfer cycles following hysteroscopic endometrial polypectomy, stratified by patient age group (≤34, 35–39, ≥40 years) and timing of discontinuation (after ET1 or ET2). The most common reasons included oocyte depletion and patient-requested discontinuation. Supplementary Table S2 presents a sensitivity analysis restricted to blastocyst transfer cycles, evaluating clinical pregnancy per cycle using generalized estimating equations clustered by patient ID. The model includes female age, number of embryos transferred, presence of at least one good-quality blastocyst, and endometrial thickness as predictors. Odds ratios with 95% confidence intervals and p-values are reported, with robust standard errors and an exchangeable working correlation structure applied. Supplementary Table S3 summarizes descriptive characteristics of the subgroup of patients who experienced at least one failed embryo transfer before hysteroscopic endometrial polypectomy and had preoperative cycle-level data available. Patient-level variables include age at surgery, infertility duration, and number of failed embryo transfer cycles before polypectomy. Cycle-level data describe the distribution of cleavage-stage versus blastocyst transfers, single versus double embryo transfers, and fresh versus frozen–thawed cycles (hormone replacement and natural), as well as protocol availability for the preoperative embryo transfer cycles.