Aneuploidy in oocytes: understanding causes and exploring therapeutic options

Ploidy in the preimplantation embryo refers to a normal chromosomal complement within each cell. It indicates properly coordinated cytoplasmic mechanisms that govern cytoskeletal organization and dynamics, which are essential for accurate chromosomal segregation during meiotic and mitotic divisions. Interruptions in upstream cytoplasmic signaling or metabolic pathways can compromise cytoskeletal function, thereby increasing the risk of aneuploidy. Thus, chromosomal abnormalities are a phenotypic manifestation of underlying cellular dysfunction, rather than the primary cause. Aneuploidy, therefore, should be viewed not merely as a genetic anomaly but as a downstream consequence of disrupted intracellular regulation, particularly during oogenesis, where the complexity of chromosomal segregation mechanisms renders the process especially vulnerable to errors. These errors, arising from compromised cytoskeletal or metabolic integrity, can manifest at multiple stages of oocyte maturation, ultimately affecting embryo viability and developmental competence. This review explores the incidence of aneuploidy across different developmental stages of oogenesis. We aim to address key questions regarding the timing of aneuploidy onset, the potential for error correction, and the prospects for therapeutic intervention. Additionally, we will explore the circumstances under which corrective strategies may offer hope to patients and when it is necessary to acknowledge the limitations of current approaches.