NPPB and congenital heart disease: Currently, some markers (such as brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP)) have been proven to be useful for the diagnosis of complex and significant congenital heart disease in neonates, children and adults [36], [37], [38], however, biomarkers for detection complex congenital heart disease in the fetus have not been reported.