Congenital Heart Disease (CHD) is the most frequent congenital defect and varies widely in severity and subtype. The antenatal diagnosis of the severity is of key importance to plan delivery and treatment. The shared developmental pathways and close functional links with the fetal heart may lead to placental dysfunction that in turn may alter the in-utero environment to the detriment of mother and fetus. Hence, assessment of placental function delivers crucial complementary information to characterize pathophysiology in CHD. This study employs high-resolution whole-placental T2* relaxometry in 75 women (40 diagnosed with a fetus with CHD) to phenotype placental function.