Pathogenesis, developmental consequences, and clinical correlations of human embryo fragmentation.

This narrative review summarizes the current state of knowledge about human embryo fragmentation during IVF. The clinical relevance of fragmentation is discussed and evidence supporting a central role for the oocyte in the pathogenesis of fragmentation is presented. A mechanism of fragmentation as aberrant cell division involving the cytoskeleton is described along with the novel concept of membrane instability in relation to follicular high-density lipoprotein metabolism and cholesterol transport.