An Updated Understanding of Human Embryonic Fragmentation.

Embryo fragmentation is a frequent occurrence in human in vitro fertilization (IVF) and has long been associated with diminished embryonic developmental potential and poorer clinical outcomes. Fragmentation, typically observed during early cleavage stages, is triggered by multifactorial influences such as oxidative stress, chromosomal instability, and compromised gamete quality. Although traditionally viewed as a marker of poor prognosis, emerging evidence indicates that mildly fragmented embryos can retain implantation potential depending on the degree and distribution of cytoplasmic fragments. This systematic review summarizes recent advances in the understanding of embryo fragmentation, emphasizing the timing, molecular mechanisms, influencing factors, and clinical relevance. Particular attention is given to the controversies surrounding fragment removal and the prospects for improving embryo assessment in clinical embryology.