Introduction
Preimplantation genetic testing for aneuploidy (PGT-A) is widely used to detect chromosomal abnormalities in embryos prior to implantation to improve the chances of a successful pregnancy. However, detecting mosaic embryos—those containing a mixture of normal and abnormal cells—presents considerable challenges. Reported mosaicism rates vary widely between 2% and 35.6%, impacted by biological complexity and technical limitations. Distinguishing true mosaicism from false positives caused by artifacts during testing remains difficult, complicating clinical decisions about whether to transfer these embryos. Additionally, understanding the origin of the chromosomal aberrations—whether from meiotic (germline) or mitotic (post-fertilization cell division) errors—and their implications for clinical outcomes is limited. This study aimed to reduce false-positive diagnoses of mosaic embryos by analyzing parental and cell-division origins of chromosomal abnormalities, thereby enhancing embryo selection and transfer strategies.
