REN and hydrops fetalis: It has been shown that circulating renin-angiotensin system (RAS) components such as angiotensin (ANG) II and aldosterone and proinflammatory cytokines (PICs) such as tumor necrosis factor-alpha (TNF-α), interleukin (IL-) 1β, and IL-6 are increased in humans and experimental animals with HF [2–4].