NPPB and hydrops fetalis: This finding confirmed earlier hypothesis-driven ‘single-factor’ studies reporting increased circulatory levels of NT-proBNP [68, 76], ST2 [3, 7, 10, 55], GDF15 [20, 28, 32, 69, 80], and IGFBP7 [21, 30, 31, 58] in patients with HF, which have been suggested to participate in the pathogenesis and progress of HF [14].