Embryos With "No Result" After PGT-A: A Retrospective Analysis of Causative Factors

Background: "No result" after PGT-A is a rare observation. Factors suspected to cause inconclusive diagnoses include poor embryo quality, day of biopsy, biopsy technique, and technical amplification failure due to diluted DNA material. This study aimed to highlight the predisposing factors that could lead to a "no result" observation after PGT-A. Results: This is a retrospective cohort study involving 177 patients and 1335 blastocysts, 1242 of which comprised the control (result) group and 93 comprised the study (no result) group. The predisposing factors studied were the number of blastocysts available for biopsy, the day of biopsy, the grade of the embryo, the degree of expansion of the blastocyst, and the grade of the trophectoderm on biopsy day. The rate of "no result" embryos did not depend on the degree of expansion of the embryo, the trophectoderm quality, the day of biopsy, or embryo grade (p=0.139, 0.34, 0.332, and 0.272, respectively). Regression analysis showed that the studied embryo characteristics were not significant predisposing factors. However, having more blastocysts to biopsy per patient was found to be a significant predictor of "no result" embryos. Conclusion: No clear embryo-related risk factors could be elucidated; however, the biopsy procedure and sample cellularity seem to be crucial components. In addition, having more embryos per patient to biopsy at a given time might increase the risk of having inconclusive biopsy results.