A Doppler is a form of ultrasound scan that helps to assess your baby's health. It measures the blood flow in different parts of your baby's body, such as his umbilical cord, brain and heart. This helps to show whether he's getting all the oxygen and nutrients he needs via the placenta.
A Doppler scan can be performed at the same time as a normal ultrasound and uses the same equipment. Most ultrasounds have a Doppler function. The person carrying out the scan (sonographer) will put some gel on your tummy and move a hand-held device (transducer) over your skin.
The transducer sends out sound waves, which bounce off the blood flow to your baby's body via the cord as well as his blood circulation system. This creates an image on a screen showing the sonographer how the blood is flowing. It gives a good idea of how your baby's doing.
The Doppler scan will take just a few minutes during your regular ultrasound scan. It all happens in real time and your sonographer will analyse the results for you.

our doctor may recommend a Doppler scan if you need extra care during your pregnancy, for example if:
you're carrying twins or more
your baby is affected by rhesus antibodies
your baby is affected by slapped cheek syndrome (parvovirus)
your baby isn't growing at a healthy rate
you've previously had a small baby
you've previously experienced a late miscarriage or suffered the loss of your baby at birth
you have an existing medical condition, such as diabetes or high blood pressure
you have a low or high BMI
you smoke If your baby is small for dates, a Doppler scan can help to show whether the placenta is working normally.