We describe the hemodynamic changes observed in fetuses with extra cardiac conditions such as intrauterine growth restriction, tumors, twin-twin transfusion syndrome, congenital infections, and in fetuses of mothers with diabetes. In most fetuses with mild extra cardiac disease, the alterations in fetal cardiac function remain subclinical. Cardiac function assessment has however helped us to achieve a better understanding of the pathophysiology of these diseases. In fetuses at the more severe end of the disease spectrum, functional echocardiography may help in guiding clinical decision-making regarding the need for either delivery or fetal therapy. The growth-restricted fetus represents a special indication for routine cardiac function assessment, as in utero hemodynamic changes may help optimize the timing of delivery. Moreover, in intrauterine growth restriction, the altered hemodynamics causes cardiovascular remodeling, which can result in an increased risk of postnatal cardiovascular disease.