JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):207
Poster Presentation
29th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263878
P-195. Relation of Morphological Evaluation in Embryos with Abnormal Fertilization and Its Impact on Blastocyst and Euploid Embryo Rates
David Timm Kvitko1, Dalana Faleiro1, Bruna Gomes Dos Santos1, Marcos Alexandre Höher1
1 Centro de Reprodução Humana Bruno Born - Lajeado - RS - Brasil
Objective: To analyze the correlation between fertilization outcomes based on morphological assessment of pronucleus (PNs) on D1—specifically comparing 2PNs, 1PN, and ≥3PNs—with blastocyst formation rates and euploid embryo rates.
Methods: A retrospective analysis was conducted on zygotes between August 2023 and June 2025, focusing on PN observation and classification (1PN, 2PNs, or ≥3PNs) 16–18 hours post-ICSI. Patients aged 30–45 years who underwent ICSI cycles with preimplantation genetic testing for aneuploidy (PGT-A) were included. Only cycles in which at least one oocyte displayed abnormal fertilization were analyzed. Embryos were cultured to the blastocyst stage and biopsied on Day 5 or Day 6 (D5–D6) for PGT-A via next-generation sequencing (NGS).
Results: Thirty ICSI cycles were included. A total of 45 abnormally fertilized oocytes were evaluated; 11 developed into blastocysts, were biopsied, and underwent PGT-A. Of these, 2 embryos were euploid and 9 were aneuploid. Among 31 embryos with 1PN, the blastocyst formation rate was 16.13%, with 40% diagnosed as euploid and 60% as aneuploid. Fourteen embryos with ≥3PNs were also assessed; 6 reached the blastocyst stage (42.86%), all of which were aneuploid (100%).
Conclusion: Embryos classified morphologically as abnormally fertilized can develop into blastocysts and, in some cases, be genetically normal (euploid). Therefore, extended culture of such embryos, followed by biopsy and genetic analysis, can provide valuable additional information to support embryo selection and inform clinical decisions. Including these embryos in the culture and evaluation process may increase the pool of viable embryos available for transfer, thereby enhancing conception chances—especially in patients with complex reproductive histories.