NPPB and hydrops fetalis: Lower serum-free thiol concentrations were associated with more advanced HF, as indicated by worse NYHA class, higher plasma NT-proBNP (P < 0.001 for both) and with higher rates of all-cause mortality (hazard ratio (HR) per standard deviation (SD) decrease in free thiols: 1.253, 95% confidence interval (CI): 1.171–1.341, P < 0.001), cardiovascular mortality (HR per SD: 1.182, 95% CI: 1.086–1.288, P < 0.001), and the composite outcome (HR per SD: 1.058, 95% CI: 1.001–1.118, P = 0.046).