FABP4 and hydrops fetalis: As shown in Supplementary Fig. 4b and 2e, compared to that in the CHD_HF and control groups, FABP4+ fibroblast expression changed the most significantly in the HHD_HF group (Fig. 2e), and FABP4 expression in the HHD_HF group was significantly greater than that in the CHD_HF group (Fig. 2e).