Center of Reproductive Medicine, The Affiliated Weihai Second Municipal Hospital of Qingdao University, Weihai, China.
Center of Reproductive Medicine, Weihai Maternal and Child Health Hospital, Weihai, China.
J Obstet Gynaecol. 2022 Oct;42(7):3322-3327. doi: 10.1080/01443615.2022.2125291. Epub 2022 Sep 23.
To investigate how different quality of day 3 (D3) embryos affect blastocyst formation and clinical outcomes. This retrospective study analysed 699 patients undergoing assisted reproductive technology (ART) between January 2017 and February 2021. A total of 2517 D3 embryos were transferred to blastocyst medium for extended culture. D3 embryos were divided into five groups. Grade A, 6-10 cells, symmetrical blastomeres and <20% fragmentation; grade B, 6-10 cells, uneven blastomeres and ≥20% fragmentation; grade C, >10 cells, symmetrical blastomeres and <20% fragmentation; grade D, >10 cells, uneven blastomeres and ≥20% fragmentation; grade E, <6 cells. Status of day 5 (D5) and day 6 (D6) blastocysts and the clinical outcomes (blastocyst transfer) of each D3 embryo were recorded. The grade C group showed a higher D5 blastocyst formation rate and a high-quality blastocyst rate than other groups (<.05). However, the clinical pregnancy rates in the grade A group were higher than other groups (<.05). Embryos with low speed of development (grade E group) showed considerable clinical outcomes that were still worth investigating. D3 embryos with less fragmentation and ≥6 symmetrical blastomeres revealed a higher developmental potential, while embryos with 6-10 blastomeres showed the ideal clinical outcomes.Impact Statement Accurate embryo evaluation can effectively reflect the developmental potential of different embryos. The number of blastomeres, proportion of fragmentation, and blastomere symmetry are three important and popular morphologic parameters used for evaluating day 3 (D3) embryos. However, in existing reports, combining these three parameters for embryo evaluation often results in different results. This is because different researchers have chosen different criteria for these three parameters. In this retrospective study, we summarised the medical records of our reproductive centre in the past three years, redefined the evaluation method of the D3 embryos, and analysed the corresponding developmental potential and clinical outcomes. We conclude that although the embryonic development potential of grade C embryos (>10 cells, symmetrical blastomeres and/or <20% fragmentation) is relatively good, the results of grade A embryos (6-10 cells, symmetrical blastomeres and/or <20% fragmentation) are better in terms of clinical outcomes. We believe this is meaningful for embryologists to choose embryos for transfer and predict the clinical outcome of IVF cycles.
为了研究不同质量的第 3 天（D3）胚胎如何影响囊胚形成和临床结局。本回顾性研究分析了 2017 年 1 月至 2021 年 2 月期间接受辅助生殖技术（ART）的 699 名患者。共将 2517 个 D3 胚胎转移到囊胚培养基中进行扩展培养。D3 胚胎分为五组。A级，6-10 个细胞，对称的卵裂球，<20%碎片；B 级，6-10 个细胞，不均匀的卵裂球，≥20%碎片；C 级，>10 个细胞，对称的卵裂球，<20%碎片；D 级，>10 个细胞，不均匀的卵裂球，≥20%碎片；E 级，<6 个细胞。记录第 5 天（D5）和第 6 天（D6）囊胚的状态以及每个 D3 胚胎的临床结局（囊胚转移）。C 级胚胎的 D5 囊胚形成率和优质囊胚率均高于其他组（<.05）。然而，A级胚胎的临床妊娠率高于其他组（<.05）。发育速度较慢的胚胎（E 级组）表现出相当可观的临床结局，仍值得研究。碎片较少且≥6 个对称卵裂球的 D3 胚胎显示出更高的发育潜力，而具有 6-10 个卵裂球的胚胎显示出理想的临床结局。
影响陈述 准确的胚胎评估可以有效地反映不同胚胎的发育潜力。卵裂球数量、碎片比例和卵裂球对称性是评估第 3 天（D3）胚胎的三个重要且流行的形态学参数。然而，在现有的报告中，结合这三个参数进行胚胎评估往往会产生不同的结果。这是因为不同的研究人员对这三个参数的选择标准不同。在这项回顾性研究中，我们总结了我们生殖中心过去三年的病历，重新定义了 D3 胚胎的评估方法，并分析了相应的发育潜力和临床结局。我们得出结论，虽然 C 级胚胎（>10 个细胞，对称的卵裂球和/或<20%碎片）的胚胎发育潜力相对较好，但 A 级胚胎（6-10 个细胞，对称的卵裂球和/或<20%碎片）的临床结局更好。我们相信这对于胚胎学家选择胚胎进行移植和预测 IVF 周期的临床结局具有重要意义。
