JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):19
Poster Presentation
29^th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263540

P-07. An Enhanced Time-Lapse System Designed to Deselect High-Grade Aneuploid Blastocysts

Hamilton de Martin¹, Eduardo Gomes Sá¹, Ellayne Cavalcanti Queiroz¹, Andrea Mesquita Lima¹, Gleicyane Sousa Santos Alam¹, Renata Reis Pimentel Castro¹, Tulius Augustus Ferreira Freitas¹, Fabio Eugênio Magalhães Rodrigues¹, Eduardo Paula Miranda¹, Sebastião Evangelista Torquato¹

¹Bios Centro de Medicina Reprodutiva - Fortaleza - CE - Brasil

Objective: To evaluate the association between inner cell mass/trophectoderm (ICM/TE) fragmentation—classified using the Blastocyst Fragmentation Indicator (BFI)—and the prevalence of high-risk chromosomal abnormalities (monosomies and chaotic aneuploidies), and to propose a clinically applicable algorithm for embryo selection and PGT-A prioritization based on BFI and maternal age.
Methods: This retrospective cohort study analyzed 1,182 blastocysts cultured individually in time-lapse incubators and biopsied for preimplantation genetic testing for aneuploidy (PGT-A) between September 2022 and December 2024. Embryos were classified by BFI: NN (no fragmentation), FN (fragmentation of ICM only), or FF (fragmentation of both ICM and TE). Aneuploidy outcomes were categorized as euploid, monosomic, chaotic, or other. Frequencies of each chromosomal abnormality type were compared across BFI classes and maternal age groups. Multinomial generalized linear models (GLM) assessed the independent predictive value of BFI and continuous maternal age for chromosomal status. Age-stratified subgroup analyses were conducted to support the development of a clinical selection algorithm.
Results: BFI was strongly associated with the incidence of high-risk aneuploidy. Among all blastocysts, NN embryos (n=745, 63.0%) showed a 63.0% euploidy rate, with 12.7% monosomic and 4.7% chaotic profiles. FN embryos (n=234, 19.8%) had higher frequencies of monosomy (34.6%) and chaotic karyotypes (19.2%), and a reduced euploidy rate of 20.1%. FF embryos (n=203, 17.2%) showed the lowest euploidy rate (6.4%), with monosomy and chaotic profiles accounting for 36.5% and 30.3%, respectively. A stepwise increase in aneuploidy severity was observed with increasing fragmentation (p<0.001). Maternal age also exerted a significant, independent effect (OR for euploidy per year=0.75; 95% CI: 0.70–0.80; p<0.001). In women <37 years, NN embryos retained a high euploidy rate (65.2%), whereas FN and FF embryos showed progressive declines. In women ≥37 years, NN euploidy decreased to 54.8%, while monosomy and chaotic forms rose to 17.4% and 7.4%, respectively. Among older patients, FF embryos had a euploidy rate of only 4.5%, with 74.4% classified as monosomic or chaotic. Multinomial GLM confirmed BFI as the strongest independent predictor: compared to NN embryos, the odds of euploidy were significantly reduced in FN (OR=0.10; 95% CI: 0.06–0.19) and FF embryos (OR=0.02; 95% CI: 0.01–0.04). Based on these data, we propose a practical, risk-stratified embryo selection strategy. For women under 37 years of age, NN embryos should be prioritized for transfer without the need for PGT-A. FN or FF embryos should only be considered if no NN embryos are available, and only after PGT-A. For women aged 37 years or older, PGT-A is recommended for all embryos, with testing prioritized in the following order: NN, then FN, and lastly FF. In this group, FF embryos have a very low probability of euploidy and should only be considered for PGT-A if no other options exist.
Conclusion: ICM/TE fragmentation, objectively assessed by the BFI, is a robust and independent marker for deselecting blastocysts with high-grade chromosomal abnormalities. The integration of BFI-based selection into clinical practice, alongside age-adjusted recommendations for PGT-A, can significantly optimize embryo transfer outcomes and rationalize resource utilization. This work establishes an evidence-based framework for embryo deselection, moving beyond traditional morphology and providing a practical algorithm to enhance safety and efficacy in assisted reproduction. This analysis represents a focused segment of a larger, ongoing investigation using the same time-lapse embryo cohort, with additional morphodynamic parameters being addressed in parallel studies.