As shown in Figure 7A and B, the AUC value of THY1, FAP, SFRP4, and MXRA5 were 0.688, 0.746, 0.908, 0.832, respectively, in the HF training set, while in the HF test set, they were 0.606, 0.748, 0.886, 0.826. Here, SFRP4 is linked to hydrops fetalis.