1302194_Table 2_Comparing Day 5 versus Day 6 euploid blastocyst in frozen embryo transfer and developing a predictive model for optimizing outcomes: a retrospective cohort study.xlsx

BackgroundOptimal protocols for frozen-thawed embryo transfer (FET) after preimplantation genetic testing (PGT) remain unclear. This study compared Day 5 (D5) and Day 6 (D6) blastocysts and evaluated predictors of FET success.
MethodsA total of 870 patients with genetic diseases or chromosomal translocations who received PGT at the First Affiliated Hospital of Zhengzhou University from January 2015 to December 2019 were recruited. All patients underwent at least one year of follow-up. Patients were divided into groups according to the blastocyst development days and quality. Univariate and multivariate logistic regression were applied to identify risk factors that affect clinical outcomes and to construct a predictive nomogram model. Area under the curve (AUC) of the subject’s operating characteristic curve and GiViTI calibration belt were conducted to determine the discrimination and fit of the model.
ResultsD5 blastocysts, especially high-quality D5, resulted in significantly higher clinical pregnancy (58.4% vs 49.2%) and live birth rates (52.5% vs 45%) compared to D6. Multivariate regression demonstrated the number of blastocysts, endometrial preparation protocol, days of embryonic development and the quality of blastocysts independently affected live birth rates (P<0.05). A nomogram integrating these factors indicated favorable predictive accuracy (AUC=0.598) and fit (GiViTI, P=0.192).
ConclusionsTransferring high-quality D5 euploid blastocysts after PGT maximizes pregnancy outcomes. Blastocyst quality, blastocyst development days, endometrial preparation protocols, and number of blastocysts, independently predicted outcomes. An individualized predictive model integrating these factors displayed favorable accuracy for counseling patients and optimizing clinical management.

背景：植入前遗传学检测（preimplantation genetic testing, PGT）后冻融胚胎移植（frozen-thawed embryo transfer, FET）的最优方案仍不明确。本研究对比第5天（Day 5, D5）与第6天（Day 6, D6）囊胚（blastocyst），并评估FET成功的预测因素。
方法：本研究于2015年1月至2019年12月期间，纳入郑州大学第一附属医院接受植入前遗传学检测的870例遗传疾病或染色体易位患者，所有患者均完成至少1年的随访。研究人员根据囊胚发育天数与质量对患者进行分组。采用单因素及多因素logistic回归（logistic regression）分析筛选影响临床结局的危险因素，并构建预测性列线图（nomogram）模型。通过受试者工作特征曲线下面积（area under the curve, AUC）及GiViTI校准带（GiViTI calibration belt）评估模型的区分度与拟合度。
结果：与D6囊胚相比，D5囊胚（尤其是优质D5囊胚）的临床妊娠率（58.4% vs 49.2%）与活产率（52.5% vs 45%）均显著更高。多因素回归分析显示，囊胚数量、子宫内膜准备方案、胚胎发育天数及囊胚质量均为活产率的独立影响因素（P<0.05）。整合上述因素的列线图模型展现出良好的预测准确性（AUC=0.598）与拟合度（GiViTI检验，P=0.192）。
结论：植入前遗传学检测后移植优质D5整倍体囊胚（euploid blastocyst）可最大化妊娠结局。囊胚质量、囊胚发育天数、子宫内膜准备方案及囊胚数量均为临床结局的独立预测因素。整合上述因素的个体化预测模型在患者咨询与优化临床管理方面具备良好的预测准确性。