Preimplantation development analysis of aneuploid embryos with different chromosomal abnormalities

Background: The change of morphokinetic pattern in aneuploid embryos will facilitate the non-invasive selection of euploid embryos. In this study, we investigated the impact of different chromosomal abnormalities on the morphokinetic patterns of embryonic development.

Methods: Our cohort includes 939 time-lapse preimplantation genetic testing cycles performed between January 2019 and July 2022 at a single academic fertility center, with a total of 2876 biopsied blastocysts. Intracytoplasmic sperm injection, blastocyst culture, trophectoderm biopsy, time-lapse monitoring, and next-generation sequencing were performed.

Results: After adjusting for patient- and cycle-related factors, six morphokinetic parameters (t5, P = 0.006; t8, P = 0.048; tSB, P < 0.001; tB,P < 0.001; t5-t2, P = 0.004; tB-tSB, P < 0.001) were significant in multilevel mixed-effects logistic regression model analysis for morphokinetic parameters to predict euploid or aneuploid embryos. None of the patient- or cycle-related factors systematically affected any morphokinetic parameter. Morphokinetic parameters of late cleavage and blastocyst stages in embryos with chromosome fragment deletion (t4 to t8, tB, t5-t2, tB-tSB, ECC2, ECC3, s2, P < 0.05) or duplication (t4, t5, tSB, tB, t5-t2, P < 0.05) were prolonged, and the morphokinetic parameters of the blastocyst stage in monosomic embryos (tSB, tB, tB-tSB, P < 0.01) were prolonged. Partial or complete chromosome 20 or 22 deletion can cause significant delays in multiple parameters of cleavage and blastocyst stages (from t4 to tB, P < 0.05).

Conclusions: Our study found that different chromosomal abnormalities have different effects on the morphokinetic parameters. Significant delays in morphokinetic parameters at different stages were found in fragment-mutated embryos and monosomic embryos. This can provide insights into the pre-implantation development pattern of aneuploid embryos and help non-invasive embryo selection.