VEGFA and polycystic ovary syndrome: Much of literature in this field has highlighted that vascular endothelial growth factor (VEGF) may be a crucial mediator of OHSS (McClure et al., 1994; Ferrara and Davis-Smyth, 1997; Agrawal et al., 1998; Garcia-Velasco and Pellicer, 2003), which is high-expressed in PCOS patients (Peitsidis and Agrawal, 2010; Almawi et al., 2016).