Light Retardance of Oocyte Components as Biomarkers for Predicting Embryo Developmental Potential

Award/Note: Int. J. Mol. Sci. 2025, 26(11), 5284; Published: 30 May 2025 / Award-Winning Paper at the 2025 Taiwan Society for Reproductive Medicine 

Authors:
En-Hui Cheng^1,2, Hui-Hsin Shih^1,3, Tsung-Hsien Lee^3,4,5, Pin-Yao Lin^2,4, Tzu-Ning Yu⁴, Chun-Chia Huang⁴, Maw-Sheng Lee^3,4,5, Chun-I Lee^4,5,6
Affiliations:
Genetic Diagnosis Laboratory, Lee Women’s Hospital [1], Post Baccalaureate Medicine, National Chung Hsing University [2], Institute of Medicine, Chung Shan Medical University [3], Division of Infertility, Lee Women’s Hospital [4], Department of Obstetrics and Gynecology, Chung Shan Medical University Hospital [5], Department of Obstetrics and Gynecology, School of Medicine, Chung Shan Medical University [6]

Study Question:

What is the chromosomal concordance between clinically biopsied trophectoderm (TE) and inner cell mass (ICM) in embryos diagnosed with segmental aneuploidy (Seg-A), and can these embryos predict implantation potential?

Study Design, Size, Duration:

A chromosomal concordance study analyzed 175 donated blastocysts from 89 couples. The study utilized embryos from IVF cycles performed between April 2017 and March 2020 at Lee Women’s Hospital (IRB: CS16105).

Materials, Setting, Methods:

The study evaluated 175 blastocysts originally classified by TE biopsy as: euploid (13), Seg-A (36), segmental mosaicism (Seg-M) (60), whole-chromosome aneuploid (Who-A) (52), and whole-chromosome mosaicism (14). Thawed blastocysts underwent ICM isolation and re-biopsy using Next-Generation Sequencing (NGS). The study compared the chromosomal status of the original TE biopsies with the ICM results to calculate concordance rates, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Main Results:

The overall TE–ICM concordance rate was 55%. Concordance was high for euploid (85%) and Who-A (94%) embryos but significantly lower for Seg-A (25%) and Seg-M (33%) embryos. Crucially, 19% of embryos diagnosed as Seg-A in the TE biopsy were found to be euploid in the ICM, while 63% of Seg-M embryos had euploid ICMs. The specificity of TE biopsy for predicting ICM euploidy in Seg-A cases was low (38.7%). No significant correlation was found between Seg-A fragment size or affected chromosomes and the resulting ICM status.

Conclusion:

This study provides valuable insights into the ambiguity of PGT-A data regarding segmental aneuploidy, emphasizing the need for cautious interpretation of the results and the development of more reliable diagnostic tools, particularly with regard to the discordance between trophectoderm and ICM results in Seg-A and Seg-M embryos. While euploid embryos remain the preferred and most reliable choice for embryo transfer, our findings support the careful consideration of Seg-A embryos in selected clinical scenarios, especially when no euploid embryos are available. Key strategies, including parental karyotyping, confirmatory re-biopsy, and the development of more accurate embryo assessment tools, will be essential in refining embryo selection and improving reproductive outcomes. These results reinforce the need for individualized counseling and thoughtful decision making in assisted reproductive technologies, rather than the routine exclusion of embryos with segmental abnormalities.