Introducing the Blastocyst Fragmentation Indicator (BFI): A Novel Time-Lapse Metric for Enhanced Aneuploidy Risk...

To propose an improved blastocyst grading system by integrating dynamic time-lapse parameters with conventional morphological criteria, aiming to enhance embryo selection during assisted reproduction.

This retrospective cohort study evaluated 1,182 embryos derived from 433 cycles of intracytoplasmic sperm injection. Time-lapse parameters included morula compaction status, blastocyst collapse frequency, and fragmentation of the inner cell mass and trophectoderm. These findings were analyzed in conjunction with standard morphological grading and embryo scoring systems based on implantation data. Embryo outcomes were stratified by chromosomal status determined through preimplantation genetic testing for aneuploidy.

Fully compacted morulae were associated with higher morphological grades; however, the proportion of chromosomally normal embryos did not differ significantly when compared to those derived from partially compacted morulae, suggesting that static morphology alone may not accurately reflect developmental potential. Although most blastocyst collapse events were minor, they correlated with increased fragmentation and reduced embryo quality. Fragmentation of the inner cell mass and/or the trophectoderm was associated with significantly lower rates of chromosomal normalcy. Logistic regression analysis confirmed fragmentation as the strongest predictor of aneuploidy, outperforming both conventional grading systems.

This integrated evaluation model, combining static morphology with dynamic developmental events, offers a more comprehensive and accurate approach to assessing embryo viability. By identifying embryos with higher risk of chromosomal abnormalities, this strategy may enhance embryo selection, improve reproductive outcomes, and contribute to more individualized care in assisted reproduction.