Clinical and morphological correlates of embryonic mosaicism: a retrospective cohort study of 10,469 blastocysts in PGT-A cycles.
Advanced maternal age independently associated with higher odds of embryonic mosaicism
Clinical and morphological correlates of embryonic mosaicism: a retrospective cohort study of 10,469 blastocysts in PGT-A cycles.
Chromosomal mosaicism presents a significant clinical and diagnostic challenge in preimplantation genetic testing for aneuploidy (preimplantation genetic testing for aneuploidy) cycles.
This study aimed to investigate the clinical and embryological factors associated with the occurrence of mosaic embryos.
This retrospective cohort study analyzed 10,469 biopsied blastocysts derived from 2,484 preimplantation genetic testing for aneuploidy cycles between January 2019 and June 2024.
The results revealed that mosaicism most frequently involved chromosomes X, 16, and 18.
Subgroup analyses confirmed consistent association between delayed blastulation, poor morphological scores, and a higher likelihood of mosaicism across diverse indications.
Notably, unlike aneuploidy-which is predominantly associated with parental age and teratozoospermia-mosaicism primarily arises from postzygotic mitotic instability, a phenomenon uniquely correlated with lower morphological grading.
Advanced maternal age and suboptimal blastocyst morphological development are independently and strongly associated with the occurrence of chromosomal mosaicism.
These findings highlight the distinct pathophysiological mechanisms and associated clinical profiles between aneuploidy and mosaicism, providing valuable reference data for prioritizing embryo selection strategies, genetic counseling and future research in preimplantation genetic testing for aneuploidy practice.