NPPB and hydrops fetalis: People with documented pre-existing HF had higher median NP levels (BNP 389 ng/L [155, 906]; NT-proBNP 2,473 ng/L [793, 6,786]) than people without documented pre-existing HF (BNP 103 [36, 296]; NT-proBNP 345 ng/L [98, 1,546]).