EIF2S2 and hydrops fetalis: A liquid biopsy approach integrating the high‐resolution RRBS DNA methylation platform and network‐oriented strategy identified the hypomethylation of CPTA1, CKAP4, SPTB, SYT6, EIF2S2, and RAB11FIP1 genes as useful biomarkers in distinguishing between ischaemic and non‐ischaemic HF aetiologies.