An umbilical artery Doppler scan is a specialized pregnancy ultrasound that evaluates the blood flow through the blood vessels in the umbilical cord. The umbilical cord connects your baby to the placenta, carrying essential oxygen and nutrients from your body to the baby.
If your referring doctor is concerned that your baby is growing too slowly, or if you have a condition like high blood pressure, this scan checks that the placenta is working efficiently and the baby is receiving adequate support.
Common Indications for an Umbilical Artery Doppler Scan
- Monitoring babies that are smaller than expected for their gestational age (fetal growth restriction).
- Checking the baby's well-being in mothers with high blood pressure or pre-eclampsia.
- Monitoring twin or multiple pregnancies.
- Evaluating the pregnancy if there is a low level of amniotic fluid (oligohydramnios).
- Following up on abnormal results from other fetal monitoring tests.
What exactly does an umbilical artery Doppler scan show?
The scan measures the resistance to blood flow in the umbilical arteries. It shows how easily blood flows from the placenta to the baby. Low resistance is healthy; high resistance indicates that the placenta is struggling to transfer nutrients and oxygen.
How should I prepare for an umbilical artery Doppler scan?
No special preparation is needed. You do not need to fast or have a full bladder, as this scan is done in the later stages of pregnancy when the womb is already enlarged.
Do I need to stop taking medication?
No. Continue taking all your medications and supplements. If you are taking blood pressure medication, take it at your normal time and inform the scan team.
What happens when I arrive for my scan?
You will go to a private scan room. You will lie on the scan couch on your back, or tilted slightly to your left side to prevent dizziness, and expose your abdomen.
How is the procedure performed?
The radiographer will apply warm gel to your abdomen and place a standard ultrasound probe over your skin. Once they locate the umbilical cord, they will switch the machine to Doppler mode. You will hear a rapid, rhythmic whooshing sound from the speaker, which is the sound of your baby’s blood flow. The machine will display waves on the screen showing the speed and pattern of the flow.
How long does an umbilical artery Doppler scan take?
The scan is relatively quick, taking about 10 to 15 minutes. It is often performed as part of a larger growth scan, which can take 30 minutes total.
Is there any discomfort?
No. The scan is painless. You will feel only the light pressure of the probe on your abdomen.
Are there risks?
No. Ultrasound uses sound waves and has no radiation risks to you or your baby.
Can children have this scan?
This scan is for pregnant patients.
Can I have this scan if I am pregnant?
Yes. This scan is designed specifically for pregnant patients, usually in the third trimester.
When will I get my results?
The blood flow measurements are calculated immediately by the scan machine. A report will be sent to your referring doctor or handed to you shortly after the scan.
What if the scan finds something?
If the scan shows increased resistance or reduced blood flow, do not panic. Your obstetrician will review these findings to decide if your baby needs closer monitoring, medication, or if it is safer to deliver the baby early.
What are the important limitations?
Ultrasound does not use ionising radiation, but a useful result still depends on the clinical question, the operator, the equipment, patient anatomy, and whether the target can be reached by sound waves. Gas, bone, body habitus, pain, movement, and a limited acoustic window can hide disease. A normal scan does not automatically exclude the suspected condition; persistent or worsening symptoms need clinical reassessment and sometimes repeat ultrasound, CT, MRI, laboratory tests, or another specialist test.
Ultrasound should be used for a medical purpose, with output and examination time kept as low as reasonably achievable—especially in pregnancy and with Doppler. Internal scans and procedures require explanation, consent, privacy, and a chaperone according to patient preference and local policy.
Questions to ask your care team
- What exact question should this ultrasound answer, and could anything important remain unseen?
- Is this a screening, diagnostic, surveillance, or procedure-guidance examination, and will the result change care?
- What preparation is required, and should I continue all medicines unless my own clinician gives different instructions?
- When will I receive the signed report, who will explain it, and what symptoms should prompt urgent assessment rather than waiting?
Sources and further reading
- RadiologyInfo.org: Obstetric ultrasound
- AIUM: Prudent clinical use and safety of diagnostic ultrasound
Conclusion
An umbilical artery Doppler scan is a safe and vital tool for checking your baby’s health when growth or placental function is in question. There is no special prep required, so simply try to relax during the quick session.