Plasma N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) concentrations are generally related to typical clinical endpoints, such as death and hospitalization [13–18], which allows drug-related reductions of NT-proBNP to predict the clinical effects of HF medications, independent of the cause of HF and other factors [19, 20]. Here, NPPB is linked to hydrops fetalis.