Does Blastocyst Morphology Influence Live Birth Rate after Frozen-thawed Single Euploid Blastocyst Transfer?

Objective: To determine whether the morphologic parameters of euploid blastocyst influence the live birth rate (LBR) following single frozen-thawed embryo transfer (FET) cycles? Methods A retrospective cohort analysis involving autologous single FET cycles after next generation sequencing (NGS) based preimplantation genetic testing for aneuploidy (PGT-A) by a large in vitro fertilization (IVF) center that was performed from June 2017 to September 2019.Women were divided into three age groups (< 30, 30–34 and ≥ 35 years old). The primary outcome measure was LBR. Outcomes were compared between different blastocyst quality (Good, Average and Poor), inner cell mass (ICM) grade (A and B), and trophectoderm (TE) grade (A, B and C). Results A total of 232 FET cycles were included, the live birth rate was 48.28%. In the youngest group (< 30 years old, n = 86), LBR were compared between cycles with various blastocyst quality (72.22% for good quality, 54.55% for average quality and 34.78% for poor quality; P  = 0.019), ICM grade (70.59% for grade A and 42.03% for grade B; P  = 0.035) and TE grade (85.71% for grade A,57.58% for grade B and 34.78 for grade C; P  = 0.015). Nevertheless, either in the 30–34 years group (n = 99) or in the oldest group (≥ 35years, n = 47), LBR were also comparable between these subgroups, no significant difference was showed in blastocyst morphologic parameters and LBR ( P  > 0.05). Furthermore, in the similarly graded euploid blastocysts, there was also no statistical significance in LBR among different age subgroups ( P  > 0.05). Conclusions In women ≥ 30 years old, euploid blastocyst quality was not associated with the LBR in FET cycles, highlights the development competence of poor-quality euploid blastocysts.