The correlation between blastocyst morphological parameters and chromosomal euploidy, aneuploidy and other chromosomal abnormalities following pre-implantation genetic testing-a single center retrospective study.

Purpose: To examine the association between blastocyst morphology and chromosomal status utilizing pre-implantation genetic testing for aneuploidy (PGT-A).

Methods: A single-center retrospective cohort study including 169 in-vitro fertilization cycles that underwent PGT-A using Next Generation Sequencing (2017-2022). Blastocysts were morphologically scored based on Gardner and Schoolcraft's criteria. Chromosomal analysis results included: euploid; aneuploid (single or double); segmental; mosaic; and complex (≥ 3 chromosome abnormalities). We examined associations between morphological parameters and chromosomal statuses of biopsied embryos utilizing multivariate logistic regression.

Results: Overall, 855 blastocysts underwent PGT-A (PGT-A alone: N = 804; unaffected PGT for monogenic disease (PGT-M) embryos along with PGT-A: N = 51). Of these, 826 were successfully analyzed, with 321 euploid embryos (38.86%). Various morphological parameters (embryo quality, inner cell mass (ICM), trophectoderm (TE), and expansion stage) were more frequent within the double (n = 72, 8.72%), complex (n = 97, 11.74%), mosaic (n = 139, 16.83%), and segmental aneuploidy (n = 28, 3.39%) groups, with similar associations between different morphological parameters and single aneuploidy (n = 169, 20.46%). Utilizing multivariate logistic regression, higher expansion, embryo quality, and TE and ICM grades, were associated with increased odds of euploidy (versus non-euploidy). Higher expansion was a positive predictor of single versus double aneuploidy (aOR 2.94, 95% CI 1.52-5.56, p = 0.001); and higher ICM grade was a positive predictor of single versus complex aneuploidy (aOR 2.86, 95% CI 1.15-7.12, p = 0.024). No morphological parameter was found to be associated with single versus mosaic aneuploidy.

Conclusion: Various morphological parameters are associated with euploidy and different aneuploidy statuses of pre-implantation blastocysts. These findings may aid in the selection of the assumed best chromosomally structured blastocyst for transfer when PGT-A is not performed.