Umbilical artery Doppler is an ultrasound test that checks how blood flows from the placenta to your baby through the umbilical cord. Normal results usually suggest that blood is moving well, while abnormal results may indicate that the placenta is not supplying blood as effectively as expected. Doctors interpret the findings alongside your baby's growth, weeks of pregnancy, and other scan results to decide whether closer monitoring is needed.
What does an umbilical artery Doppler test measure?
An umbilical artery Doppler is a special type of ultrasound used during pregnancy to assess blood flow in the umbilical cord. The cord contains blood vessels that connect the baby with the placenta, which supplies oxygen and nutrients. The test measures the speed and pattern of blood moving through an umbilical artery during the baby's heartbeat.
According to the American College of Obstetricians and Gynecologists (ACOG), this test is used with other assessments when a baby may not be growing as expected. It is particularly useful when doctors need to assess how well the placenta is supporting fetal growth.
How do you interpret normal and abnormal results?
Your report may describe blood flow as normal, elevated, reduced, absent, or reversed. These terms describe different patterns of blood movement, not a diagnosis by themselves. The meaning of a result depends on the pregnancy's stage, the Doppler measurements, and the baby's overall condition.
Normal umbilical artery Doppler results
A normal result generally means that blood continues to flow through the umbilical artery during the entire heartbeat cycle, including the period when the heart relaxes between beats. The resistance to blood flow is within the expected range for the stage of pregnancy.
Normal findings are reassuring because they suggest that blood is moving through the placenta and umbilical cord as expected. However, doctors still consider fetal growth, amniotic fluid levels, and other relevant scan findings when assessing the pregnancy.
High resistance or an elevated Doppler reading
If the report shows high resistance, increased pulsatility, or an elevated pulsatility index, blood may be meeting more resistance as it passes through the placental circulation. This can be associated with placental insufficiency, meaning the placenta may not be functioning as effectively as expected.
An elevated reading does not automatically mean that the baby is in immediate danger. The obstetric team will consider how far the measurement is outside the expected range, whether the baby is growing appropriately, and whether the finding is changing over time.
Absent end-diastolic flow
End-diastolic flow refers to blood moving through the umbilical artery when the baby's heart relaxes between beats. When the report says absent end-diastolic flow (AEDF), it means that forward blood flow is not detected during this part of the heartbeat cycle.
This is an important abnormal finding, particularly when fetal growth restriction is present. It may indicate significant resistance in the placental circulation and usually requires prompt specialist assessment and closer fetal monitoring.
Reversed end-diastolic flow
Reversed end-diastolic flow (REDF) means that blood briefly moves in the opposite direction during the relaxation phase of the heartbeat rather than continuing forward. This is a more concerning Doppler pattern than absent end-diastolic flow.
According to ACOG guidance on fetal surveillance, absent or reversed end-diastolic flow in a pregnancy affected by fetal growth restriction is associated with increased risk. Reversed flow may require hospital-based monitoring and consideration of earlier delivery, depending on the gestational age and the full clinical picture.