Checking your baby’s blood supply (uterine artery doppler ultrasound measurement)

Read our guide about how to check your baby’s blood supply.

You can also download a PDF of this information by following the link on the right.

What is a uterine artery doppler ultrasound measurement?

Uterine arteries carry blood to your uterus (womb). A uterine artery doppler ultrasound measurement checks the blood flow between you and your baby.
We do this during an ultrasound scan.

The doppler measurements use sound waves to check if the blood
is flowing easily (low resistance) or if it’s having to work harder to flow (raised resistance).

When does the measurement take place?

If you’re pregnant with one baby, we do the measurement during the second scan we offer you during your pregnancy, at approximately 20 weeks. We usually refer to this as your anomaly
scan.

If you’re pregnant with more than one baby, we’ll schedule you for additional scans. This is where we check your babies growth.

What do the results mean?

A low resistance measurement means that a good, steady amount of blood is reaching your baby, helping it continue to grow well. It also indicates a lower chance of you developing preeclampsia (a problem with high blood pressure) during pregnancy.

4 in 100 people show a raised resistance in the blood flow. This may indicate a higher chance that your baby may not grow as well as expected or that you may develop preeclampsia in pregnancy.

What if I have a scan that shows raised resistance?

A raised resistance doesn’t mean that you’ll develop pre-eclampsia or
your baby will have slow growth. It just means it’s more likely.

1 in 4 people who have a raised resistance develop one of these conditions.

To be safe, if you have a raised resistance, we’ll recommend closer monitoring, which will mean more regular blood pressure checks and extra scans.

Your sonographer will refer you for an antenatal clinic appointment at
28 weeks to discuss this. This means that if problems start to happen, we’ll pick them up as early as possible and recommend actions for you and your baby.

If you have any more questions, talk to your midwife.

About this patient information

This is intended as general information only. We aim to make the information as up to date and accurate as possible, but it’s subject to change.

Always check specific advice on any concerns you may have with your doctor.