Objective:To explore the clinical outcome of blastocysts with different developmental time and grades of preimplantation genetic testing for aneuploidies (PGT-A) embryo transfer cycles, and to compare and analyze their transcriptome characteristics.Methods:The clinical data of patients with euploid blastocyst transplantation selected by PGT-A in Center for Reproductive Medicine of Women Health Center of Shanxi from January 2017 to December 2021 were retrospectively analyzed. A total of 295 transplantation cycles were divided into groups according to the day of embryo blastulation [day 5 (D5) group and day 6 (D6) group] and blastocyst grade (good-quality group and fair-quality group) and their clinical outcomes were compared. By comparing the single-cell RNA sequencing (scRNA-seq) data of blastocysts of different developmental time and grades from GEO and ENA data platforms, the transcriptome level differences among different groups were analyzed.Results:1) There were no significant differences in age of male and female, type of infertility, infertility duration, body mass index (BMI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol and number of oocytes retrieved between D5 and D6 groups (all P>0.05). The M Ⅱ oocyte rate [86.35% (2051/2375) vs. 82.71% (1770/2140), P=0.001], blastocyst formation rate [68.08% (725/1065) vs. 62.14% (540/869), P=0.006], implantation rate [72.78% (115/158) vs. 52.55% (72/137), P<0.001], clinical pregnancy rate [56.33% (89/158) vs. 43.80% (60/137), P=0.032] and live birth rate [53.80% (85/158) vs. 40.87% (56/137), P=0.027] in D5 group were significantly higher than those in D6 group, and the results of miscarriage rate, preterm birth rate, proportion of male and birth weight between the two groups were not statistically significant. 2) There were no significant differences in age of male and female, type of infertility, infertility duration, BMI, FSH, LH, estradiol and number of oocytes retrieved between good-quality and fair-quality groups (all P>0.05). The M Ⅱ oocyte rate [87.06% (1251/1437) vs. 83.50% (2570/3078), P=0.002], blastocyst formation rate [73.38% (499/680) vs. 61.08% (766/1254), P<0.001], implantation rate [77.90% (74/95) vs. 56.50% (113/200), P<0.001], clinical pregnancy rate [61.05% (58/95) vs. 45.50% (91/200), P=0.013] and live birth rate [56.84% (54/95) vs. 43.50% (87/200), P=0.032] in good-quality group were significantly higher than those in fair-quality group, and the results of miscarriage rate, preterm birth rate, proportion of male and birth weight between the two groups were not statistically significant. 3) Based on the scRNA-seq data from GEO and ENA data platforms, we mined differentially expressed genes (DEGs) in the inner cell mass (ICM) and trophectoderm (TE) of D5 and D6 blastocysts, good-quality blastocysts and fair-quality blastocysts. Compared with D6 group, KEGG enrichment analysis showed that DEGs up-regulated of ICM/TE in D5 group were significantly enriched in 285/288 signaling pathways. DEGs up-regulated of ICM/TE were significantly enriched in 207/3 signaling pathways in the good-quality group compared with the fair-quality group. Conclusion:In terms of implantation and clinical pregnancy ability, D5 blastocysts were better than D6 blastocysts, and good-quality blastocysts were better than fair-quality blastocysts. Transcriptome level analysis of blastocysts with different developmental time and grades showed significant differences in transcriptome characteristics. The analysis of blastocyst transcriptome level has predictive value for blastocyst implantation and clinical pregnancy ability.

Objective:To explore the clinical outcome of blastocysts with different developmental time and grades of preimplantation genetic testing for aneuploidies (PGT-A) embryo transfer cycles, and to compare and analyze their transcriptome characteristics.Methods:The clinical data of patients with euploid blastocyst transplantation selected by PGT-A in Center for Reproductive Medicine of Women Health Center of Shanxi from January 2017 to December 2021 were retrospectively analyzed. A total of 295 transplantation cycles were divided into groups according to the day of embryo blastulation [day 5 (D5) group and day 6 (D6) group] and blastocyst grade (good-quality group and fair-quality group) and their clinical outcomes were compared. By comparing the single-cell RNA sequencing (scRNA-seq) data of blastocysts of different developmental time and grades from GEO and ENA data platforms, the transcriptome level differences among different groups were analyzed.Results:1) There were no significant differences in age of male and female, type of infertility, infertility duration, body mass index (BMI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol and number of oocytes retrieved between D5 and D6 groups (all P>0.05). The M Ⅱ oocyte rate [86.35% (2051/2375) vs. 82.71% (1770/2140), P=0.001], blastocyst formation rate [68.08% (725/1065) vs. 62.14% (540/869), P=0.006], implantation rate [72.78% (115/158) vs. 52.55% (72/137), P<0.001], clinical pregnancy rate [56.33% (89/158) vs. 43.80% (60/137), P=0.032] and live birth rate [53.80% (85/158) vs. 40.87% (56/137), P=0.027] in D5 group were significantly higher than those in D6 group, and the results of miscarriage rate, preterm birth rate, proportion of male and birth weight between the two groups were not statistically significant. 2) There were no significant differences in age of male and female, type of infertility, infertility duration, BMI, FSH, LH, estradiol and number of oocytes retrieved between good-quality and fair-quality groups (all P>0.05). The M Ⅱ oocyte rate [87.06% (1251/1437) vs. 83.50% (2570/3078), P=0.002], blastocyst formation rate [73.38% (499/680) vs. 61.08% (766/1254), P<0.001], implantation rate [77.90% (74/95) vs. 56.50% (113/200), P<0.001], clinical pregnancy rate [61.05% (58/95) vs. 45.50% (91/200), P=0.013] and live birth rate [56.84% (54/95) vs. 43.50% (87/200), P=0.032] in good-quality group were significantly higher than those in fair-quality group, and the results of miscarriage rate, preterm birth rate, proportion of male and birth weight between the two groups were not statistically significant. 3) Based on the scRNA-seq data from GEO and ENA data platforms, we mined differentially expressed genes (DEGs) in the inner cell mass (ICM) and trophectoderm (TE) of D5 and D6 blastocysts, good-quality blastocysts and fair-quality blastocysts. Compared with D6 group, KEGG enrichment analysis showed that DEGs up-regulated of ICM/TE in D5 group were significantly enriched in 285/288 signaling pathways. DEGs up-regulated of ICM/TE were significantly enriched in 207/3 signaling pathways in the good-quality group compared with the fair-quality group. Conclusion:In terms of implantation and clinical pregnancy ability, D5 blastocysts were better than D6 blastocysts, and good-quality blastocysts were better than fair-quality blastocysts. Transcriptome level analysis of blastocysts with different developmental time and grades showed significant differences in transcriptome characteristics. The analysis of blastocyst transcriptome level has predictive value for blastocyst implantation and clinical pregnancy ability.