Evaluation of the clinical utility of poor-quality embryos using an extended in vitro embryo culture system

抄録

There is limited consensus among embryologists regarding the decision to freeze or discard borderline-quality blastocysts. This study aims to investigate the intrinsic developmental potential of blastocysts with poor inner cell mass (ICM) or trophectoderm (TE) quality using an in vitro three-dimensional (3D) culture system that excludes maternal factors. A total of 51 one-pronucleus (1PN)-derived blastocysts were obtained from couples undergoing assisted reproduction technology (ART). The embryos were categorized into three groups: 20 high-quality embryos, 17 embryos with poor ICM, and 14 embryos with poor TE. A 3D culture system was utilized to assess the post-implantation developmental potential of blastocysts with varying grades. Embryonic morphology and diameter were measured to evaluate growth characteristics, and immunofluorescence staining was performed to assess the differentiation of embryonic lineages. 35% of high-quality 1PN embryos developed into OCT4 + epiblast (EPI), GATA6 + hypoblast (HYP), and CK7 + TE, along with an amniotic cavity and yolk sac. Blastocysts with poor TE quality demonstrate reasonable developmental potential, whereas those with poor ICM quality are already compromised during implantation. This study provides valuable insights for ART and clinical management of low-quality blastocysts.