NPPB and hydrops fetalis: According to the cutoff value of HFEI and NT-proBNP, HF patients were divided into the following four groups: group A: HFEI<3.5 and NT-proBNP<3000 pg/ml; group B: HFEI<3.5 and NT-proBNP>3000 pg/ml; group C: HFEI>3.5 and NT-proBNP<3000 pg/ml; group D: HFEI>3.5 and NT-proBNP>3000 pg/ml.