Ma Bing-Xin, Yang Liu, Tian Yu, Jin Lei, Huang Bo
Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Jiangsu Hengrui Pharmaceuticals Co., Ltd., Shanghai, China.
Front Med (Lausanne). 2022 Jul 28;9:934327. doi: 10.3389/fmed.2022.934327. eCollection 2022.
Elective single blastocyst transfer (eSBT) is considered to reduce the incidence of multiple pregnancy compared to double embryo transfer. Blastocyst selection is the key to achieving pregnancy. In the past, morphological assessment was the main criterion used to select blastocyst. Some important morphological parameters are considered to be clinically valuable, such as cytoplasmic strings traversing from the inner cell mass (ICM) and mural trophectoderm (mTE).
In this study, 1,267 elective frozen-thawed eSBT cycles cultured in a time-lapse culture system from January 2018 to May 2019 were included. Blastocysts were grouped into "present" and "absent" according to the appearance of cytoplasmic strings between ICM and mTE cells. The "present" group was further categorized according to the quantity of cytoplasmic strings between the ICM and mTE cells.
A time-lapse analysis indicated that cytoplasmic strings between ICM and mTE were more visible among good quality blastocysts. Furthermore, blastocysts with cytoplasmic strings showed higher clinical pregnancy and live birth rates ( = 0.011 and 0.003), while no significant differences were observed in abortion rate and birth weight ( = 0.466 and 0.556).
In conclusion, although the results of previous studies about cytoplasmic strings have been controversial, the present time-lapse analysis provides evidence for the first time that cytoplasmic strings between ICM and mTE cells are a positive predictor of clinical pregnancy and live birth outcomes in elective frozen-thawed single blastocyst transfer cycles.
与双胚胎移植相比，选择性单囊胚移植（eSBT）被认为可降低多胎妊娠的发生率。囊胚选择是实现妊娠的关键。过去，形态学评估是选择囊胚的主要标准。一些重要的形态学参数被认为具有临床价值，例如从内细胞团（ICM）和壁滋养外胚层（mTE）穿过的细胞质条索。
本研究纳入了2018年1月至2019年5月在延时培养系统中培养的1267个选择性冻融eSBT周期。根据ICM和mTE细胞之间细胞质条索的出现情况，将囊胚分为“有”和“无”两组。“有”组进一步根据ICM和mTE细胞之间细胞质条索的数量进行分类。
延时分析表明，在优质囊胚中，ICM和mTE之间的细胞质条索更明显。此外，有细胞质条索的囊胚临床妊娠率和活产率更高（P = 0.011和0.003），而流产率和出生体重无显著差异（P = 0.466和0.556）。
总之，尽管先前关于细胞质条索的研究结果存在争议，但目前的延时分析首次提供证据表明，ICM和mTE细胞之间的细胞质条索是选择性冻融单囊胚移植周期中临床妊娠和活产结局的阳性预测指标。
