VEGFA and ovarian hyperstimulation syndrome: Development of OHSS in women undergoing ART depends on the presence of functional ovaries and the administration of hCG.[3] It is thought that hCG increases vascular permeability leading to ascites and other complications of OHSS through vascular endothelial growth factor (VEGF) system, composed of ligands and receptors, which plays a pivotal role in the pathophysiology of OHSS.