EDN1 and hydrops fetalis: Previous studies have revealed several biomarkers with prognostic value for HF, such as B-type natriuretic peptide (BNP),[3] N-terminal proBNP (NT-proBNP),[3] mid-regional proatrial natriuretic peptide,[4] high sensitivity C-reactive protein,[3] and endothelin-1 (ET-1).[5] Among them, only BNP and NT-proBNP have been recommended by current guidelines.[6]