JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):131
Poster Presentation
29th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263766
P-119. How do different chromosomal constitutions affect embryo development up to the blastocyst stage?
Juliana Polisseni Magalhaes1, Gabriela Boseja Conde Duarte2, Lucas Polisseni Souza3, Larissa Milani Coutinho1
1 NIDUS - Juiz de Fora - MG – Brasil
2 UFJF - Universidade Federal de Juiz de Fora - Juiz de Fora – MG – Brasil
3 Faculdade Suprema - Juiz de Fora – MG – Brasil
Objective: Aneuploidies are known to affect preimplantation development, potentially leading to embryo arrest and altered cell division patterns. However, the specific effects of varying chromosomal constitutions on developmental trajectories up to the blastocyst stage remain largely unexplored. This study aimed to evaluate the correlation between the day of blastocyst formation (D5, D6, D7) and the ploidy of embryos undergoing biopsy for preimplantation genetic testing (PGT). Additionally, it aimed to investigate whether an association exists between slower embryonic development and the number of aneuploidies detected in the embryos.
Methods: This retrospective cross-sectional study analyzed medical records from a private fertility clinic in Brazil. All IVF cycles with blastocyst biopsy for PGT performed between January 2024 and June 2025 were included. Cycles involving non-PGT indications or with incomplete data were excluded. Blastocysts were allocated into three groups according to the day of biopsy: D5, D6, and D7, and PGT results were analyzed. The association between the day of biopsy and the number of aneuploidies was also evaluated. Statistical analyses were performed with the Chi square test and Fisher test (p<0.05).
Results: The mean maternal age was 39.6±0.30 years. A total of 286 blastocysts from 89 IVF cycles were analyzed, yielding an overall euploidy rate of 22.70% (n=65). When stratified by biopsy day, D5 (n=162) and D6 blastocysts (n=111) had similar aneuploidy rates of 77.3% and 77.2%, respectively. In contrast, D7 (n=13) blastocysts exhibited the highest aneuploidy rate of 84.6%, but the data were not statistically different (p=0.65). When the number of aneuploidies per blastocyst was analyzed, single chromosomal aneuploidies were more prevalent in embryos biopsied on day 5 and day 6 (25.6% and 28.2%, respectively), when compared with D7 (18.2%). While cases of more than four aneuploidies were predominantly found in the group biopsied on day 7 (36.4%), when compared with D5 and D6 (17.6% and 15.3%). No statistically significant difference was identified between the groups (p=0.23).
Conclusion: While the present findings do not allow for exact or definitive conclusions due to the exploratory nature and sample size, a trend was observed, suggesting a relationship between higher aneuploidy complexity and slower embryonic development to the blastocyst stage. It is crucial to emphasize that our results are still preliminary, and validation of this hypothesis will require a study with a significantly larger sample to establish more robust and generalizable conclusions.