Keeping the foramen ovale and ductus arteriosus open and blood flowing during pregnancy is necessary to maintain normal fetal circulation. If the foramen ovale is closed, or becomes too small to pass blood flow efficiently, the fetal circulation will be abnormal, such as edema and a faster or slower heart rate. Therefore, if everything is in good condition in the fetus, it is likely that the ultrasound measurement is off. Distortion of the arterial duct does not affect blood flow through and is of little clinical significance. However, as a precautionary measure, the fetal heart should be monitored and the cardiac ultrasound should be repeated if necessary.