FSTL3 and hydrops fetalis: We identified several established markers of HF risk (NT-proBNP, GDF-15)19,20, confirmed previously described associations of other proteins with incident HF (e.g. SPON18–10, THBS25,7, GHR6, IFGBP25,6, C97, osteoprotogerin8,10, MMP128–10), and identified several proteins not previously associated with incident HF (e.g. SVEP1, FSTL3, APOF, ANGPTL3, IGFBP7, CCL15, and ITIH3 among others).