Reproductive Medicine Center, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.
Front Endocrinol (Lausanne). 2021 Feb 24;12:621221. doi: 10.3389/fendo.2021.621221. eCollection 2021.
The scoring system for human blastocysts is traditionally based on morphology; however, there are controversies on the effect of morphology parameters on pregnancy outcomes. The aim of this study is to evaluate the predicting value of each morphology parameter on pregnancy outcomes in a setting of single embryo transfer.
This is a retrospective cohort study on patients undergoing frozen-thawed single blastocyst transfer at our center, between Jan. 2009 and Dec. 2018. A total of 10,482 cycles were analyzed. The blastocysts were scored according to the expansion and hatching status, morphology of inner cell mass (ICM), and cells of trophectoderm (TE). The primary outcome measure was live birth rate. One-way analysis of variance, chi-square test, and multiple logistic regression were used for statistical analysis.
The clinical pregnancy rate was lower in the blastocysts of stage 3 (48.15%), compared with those of stage 4 (56.15%), stage 5 (54.91%), and stage 6 (53.37%). The live birth rate was lower in the blastocysts of stage 3 (37.07%), compared with those of stage 4 (44.21%) and stage 5 (41.67%). The rates of clinical pregnancy (A: 66.60%, B: 53.25%, C: 39.33%) and live birth (A: 54.62%, B: 41.29%, C: 28.45%) were both decreased with decreasing grade of ICM morphology, and these differences were pairwise significant. The miscarriage rate of blastocysts with ICM grade A was lower, compared with ICM grade C (17.53 27.66%). Blastocysts with TE morphology of C had lower rates of clinical pregnancy (43.53%) and live birth (32.57%), compared with those with TE morphology of A and B (clinical pregnancy rate: 64.26% for A, 58.11% for B; live birth rate: 52.74% for A, 45.64% for B). There were no significant differences in rates of clinical pregnancy, live birth, and miscarriage between the blastocysts with TE grade A and B.
The blastocyst expansion stage, ICM grade, and TE grade are all associated with pregnancy outcomes. ICM grade is the strongest predictor of live birth. A blastocyst with stage 4-5, ICM grade A, and TE grade A/B should be given priority for single embryo transfer.
人类囊胚的评分系统传统上基于形态学，但形态学参数对妊娠结局的影响存在争议。本研究旨在评估在单胚胎移植环境下，每个形态学参数对妊娠结局的预测价值。
这是一项对 2009 年 1 月至 2018 年 12 月在我院行冷冻解冻单囊胚移植的患者进行的回顾性队列研究。共分析了 10482 个周期。囊胚根据扩张和孵化状态、内细胞团（ICM）形态和滋养外胚层（TE）细胞进行评分。主要结局指标为活产率。采用单因素方差分析、卡方检验和多因素逻辑回归进行统计学分析。
3 期囊胚的临床妊娠率（48.15%）低于 4 期（56.15%）、5 期（54.91%）和 6 期（53.37%）。3 期囊胚的活产率（37.07%）低于 4 期（44.21%）和 5 期（41.67%）。ICM 形态等级降低，临床妊娠率（A：66.60%，B：53.25%，C：39.33%）和活产率（A：54.62%，B：41.29%，C：28.45%）均降低，且两两比较差异均有统计学意义。ICM 分级为 A 的囊胚流产率低于 C 级（17.53%比 27.66%）。TE 形态为 C 的囊胚临床妊娠率（43.53%）和活产率（32.57%）均低于 TE 形态为 A 和 B 的囊胚（临床妊娠率：A 级为 64.26%，B 级为 58.11%；活产率：A 级为 52.74%，B 级为 45.64%）。TE 分级为 A 和 B 的囊胚之间临床妊娠率、活产率和流产率无显著差异。
囊胚扩张阶段、ICM 分级和 TE 分级均与妊娠结局相关。ICM 分级是活产的最强预测因素。具有 4-5 期、ICM 分级 A 和 TE 分级 A/B 的囊胚应优先进行单胚胎移植。
