TNF and Pleural effusion: Emerging evidence has shown that OHSS is associated with inflammatory factors interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-8, vascular endothelial growth factor, and the local renin-angiotensin aldosterone system, which led to a series of pathologic changes, including increased capillary permeability, leakage of vascular fluid into the interstitial space to form pleural effusions or ascites, decreased effective circulating blood volume, blood concentration, and even thrombosis (6, 7).