The umbilical arteries are typically two arteries within the umbilical cord that carry deoxygenated blood and waste products from the fetus to the placenta for gas exchange. Doppler evaluation of the umbilical artery is one of the most important assessments in high-risk obstetrics, as the waveform pattern reflects the resistance to blood flow in the placental vascular bed. A normal umbilical artery waveform shows continuous forward flow throughout the cardiac cycle. Absent end-diastolic flow or reversed end-diastolic flow are abnormal findings that indicate significantly increased placental resistance and are associated with fetal growth restriction, fetal distress, and increased risk of perinatal death. A single umbilical artery (only one artery instead of two) is a relatively common finding that may be associated with other congenital anomalies.
Sonography Term