Doppler Scan checks blood flow patterns in different vessels. We specialise in maternal-fetal blood flow assessment, our Doppler ultrasound offers crucial insights into fetal health, including heart and circulatory function.
Carried out as a comfortable abdominal scan on your clinician's referral, with the blood-flow measurements reviewed by our specialist fetal medicine team and a report sent promptly to your doctor or midwife.
Available atLPC City (E1)
The Doppler technique in ultrasound pregnancy is a method that uses sound waves to detect the movement of blood in vessels, specifically the movement of red blood cells. It is used to study blood circulation in the fetus, uterus, and placenta.
Doppler ultrasound can be used to assess blood flow to the placenta and through the umbilical cord, and it plays a crucial role in identifying the ‘at risk’ fetus and screening for potential complications in pregnancy.
This technique provides important information about blood flow through the circulatory system, helping healthcare providers screen for diseases, diagnose problems, and evaluate the effectiveness of treatments.
Your baby depends entirely on a steady supply of oxygen and nutrients, carried through the placenta and along the umbilical cord. When that supply is healthy, your baby has what it needs to grow. When blood flow is reduced, often because the placenta is not working as well as it should, a baby may grow more slowly than expected. A Doppler scan is the tool that lets us look at this circulation directly, rather than only measuring your baby's size.
This matters most for babies who are smaller than expected. Fetal growth restriction, where a baby has not grown as well as it should, is one of the situations in which extra Doppler monitoring is offered, according to the pregnancy charity Tommy's.
Measuring the blood flow through the umbilical cord helps a clinical team judge whether a small baby is simply constitutionally small and well, or whether it needs closer watching (RCOG patient information).
Blood flow in the arteries supplying the womb matters too: uterine artery Doppler contributes to assessing the risk of pre-eclampsia, which is why it often forms part of pre-eclampsia screening.
There is good evidence behind this approach. In pregnancies already considered higher risk, using umbilical artery Doppler has been associated with fewer deaths around the time of birth — around 1.2 per cent compared with 1.7 per cent in a large Cochrane review of more than 10,000 babies. Where your baby's growth is the focus, a Doppler scan is often combined with a growth scan or wellbeing scan.
A few key facts about how Doppler ultrasound is used in pregnancy.
Doppler ultrasound is a special scan we use during pregnancy to check the blood flow in your baby’s heart, its vessels, and your uterine arteries. Fetal Spectral Doppler is particularly useful for monitoring smaller babies, babies with anaemia, or if you have certain health conditions.
It’s important to know that Doppler scans aren’t needed for all pregnancies. They are mainly recommended if there are specific concerns about your baby’s health, growth, or development. Please ask your health provider if you need the Doppler ultrasound.
Yes, we can perform various maternal-fetal Doppler scans as recommended by your healthcare provider. After the scan, we’ll promptly send a report of the findings to them. However, it’s important to note that we don’t use Doppler scans routinely, as their role in pregnancy screening is still a subject of ongoing medical debate.
We offer a range of Doppler scans, but we need a written or emailed request from your doctor or midwife, including their clearly indicated contact information (email, mobile phone number), before we can proceed. The types of Doppler scans we can perform include:
We use Colour Doppler, an advanced noninvasive ultrasound technology, to help rule out fetal anomalies. This means we perform an abdominal scan, also known as an external scan. This method visualises blood flow within the heart and blood vessels, providing detailed images of structures receiving blood. It’s especially useful for examining the fetal heart (fetal echocardiography) and for screenings like vasa previa.
A Doppler scan is arranged on your clinician's request, so please have the written or emailed referral from your doctor or midwife ready when you book. It should include their contact details so we can send your results back to them.
Most Doppler scans are performed through the abdomen, so nothing needs to enter your body, and for most appointments no special preparation is needed — you can usually eat and drink as normal. If anything specific would help for your particular assessment, we will let you know when you book.
A sonographer applies warm gel and moves a small probe across your tummy. Colour Doppler shows blood moving through your baby's heart and vessels, while spectral Doppler measures the speed and pattern of that flow in the vessels your clinician has asked us to assess.
The blood-flow measurements are reviewed and interpreted by specialist fetal medicine clinicians. Sonographers acquire the images and measurements, while the detailed interpretation of what they mean for your pregnancy is made by our clinical team.
We promptly send a written report of the findings to the doctor or midwife who referred you, so they can discuss the results with you and plan any further monitoring if it is needed.
Doppler results are usually described in terms of resistance — how easily blood is flowing. A low-resistance pattern means blood is reaching your baby steadily, which is reassuring. A raised-resistance pattern can suggest the placenta is having to work harder; NHS patient information explains that this usually means monitoring the pregnancy more closely, with extra scans of your baby's growth and the blood flow through the cord.
An abnormal or borderline result does not necessarily mean your baby is unwell. Often it simply means your clinical team will arrange closer monitoring — for example more frequent growth scans, or repeat Doppler assessments of the blood flow in your baby's brain and abdomen, the approach described by both RCOG and Tommy's for babies measuring small. Because a Doppler scan gives a snapshot, patterns are usually followed over time rather than judged on a single reading.
This information is intended for general educational purposes only and does not constitute medical advice. Your referring doctor or midwife will explain what your own results mean for you. If you have concerns about your pregnancy or your baby's wellbeing at any time, contact your midwife, GP or maternity unit promptly.
Yes. A Doppler scan is a form of ultrasound and, like a standard 2D scan, it uses sound waves rather than radiation, so it is considered safe in pregnancy. At London Pregnancy Clinic it is performed as an abdominal (external) scan, meaning nothing enters your body and there are no known risks to you or your baby.
A Doppler scan checks blood flow patterns in the vessels of pregnancy. It uses sound waves to detect the movement of red blood cells, allowing us to assess circulation in the fetus, uterus and placenta. This information helps to identify an 'at-risk' fetus and to screen for potential complications, particularly where there are concerns about your baby's health or growth.
A Doppler scan is not needed for every pregnancy. It is mainly recommended when there are specific concerns about your baby's health, growth or development. It can be especially useful for monitoring smaller babies, babies with anaemia, or if you have certain health conditions. Please ask your midwife or GP whether a Doppler ultrasound is right for your circumstances.
Yes. Before we can perform a Doppler scan, we need a written or emailed request from your doctor or midwife, with their contact details (email and mobile number) clearly indicated. This is because Doppler scans are recommended for specific clinical concerns rather than used routinely. After your scan, we promptly send a report of the findings back to your referring clinician.
London Pregnancy Clinic can perform a range of maternal-fetal Doppler scans as recommended by your healthcare provider. These include assessment of the uterine arteries, the umbilical arteries, the middle cerebral artery and the ductus venosus. We also use Colour Doppler to help examine the fetal heart and screen for conditions such as vasa previa. The right combination depends on your clinician's request.
A Doppler scan uses the same safe ultrasound sound waves as a standard 2D scan, but it focuses on measuring blood flow rather than only showing your baby's structures. Colour Doppler maps blood moving through the heart and vessels, which is why it is valuable for detailed heart assessment and blood-flow screening. Many patients have it alongside a routine scan such as an anomaly scan or growth scan.
You can book a Doppler scan online through our booking page or by calling 020 3687 2939, but please have your referral from your doctor or midwife ready first, as we need it before proceeding. If you are unsure whether a Doppler scan is what you need, our team is happy to talk through the options and, where appropriate, an early fetal scan or other assessment.
A Doppler scan is usually quick — most take around 15 to 30 minutes, depending on which vessels your clinician has asked us to assess. It is carried out through your abdomen with warm gel and a small probe, so it is painless and nothing needs to enter your body. If it is combined with another scan, your appointment may be a little longer.
For most Doppler scans, no special preparation is needed — you can eat and drink as normal, and there is no need to arrive with a full bladder. The scan is carried out through your abdomen with gel and a small probe. If anything specific would help for your particular assessment, we will let you know when you book, once we have your referral.
Raised resistance on a Doppler scan means blood is not flowing quite as freely as expected, most often because the placenta is working harder than usual. In practice, the most common next step is closer monitoring — repeat scans over the following days or weeks — so your team can see how the pattern develops (RCOG patient information). A single reading is rarely the whole picture, because Doppler patterns are followed over time. Your referring doctor or midwife will explain what your own results mean for you and discuss any next steps.
The timing depends on the reason for the scan. Uterine artery Doppler is often performed around 18 to 21 weeks, at the same time as the anomaly scan (NHS patient information). Umbilical artery and other fetal Doppler assessments are more commonly done later in pregnancy, particularly in the third trimester if there are concerns about a baby's growth. Your clinician will advise the right timing for your situation.
Colour Doppler maps where blood is moving, overlaying colour onto the ultrasound image. Spectral (pulsed-wave) Doppler adds a measurement: it records the speed and pattern of flow in a single vessel as a waveform, which is what allows the resistance in the umbilical or uterine arteries to be assessed against the expected range for your stage of pregnancy. In practice, the two are usually used together during the same scan.
Contact
The figures and clinical statements on this page are drawn from the sources below. Guidance evolves — always discuss your individual circumstances with a clinician.
Cookies on this site
We use cookies needed to run this site. With your permission we would also use analytics and advertising cookies to see how the site is used and which of our adverts lead to bookings. Declining will not affect your care or your booking. See our Privacy notice and Terms & Conditions.
