Understanding the different pregnancy scan names can feel overwhelming, particularly when each examination has a specific purpose, a recommended window of gestational age and terminology that varies between healthcare settings. This guide explains the main types of pregnancy scans used in the UK, what each scan is designed to assess and when it is typically offered, so you can approach your antenatal appointments with greater confidence.
What Are Pregnancy Scans?
Pregnancy scans use ultrasound technology to create images of the developing baby, the placenta and the uterus. During an ultrasound examination, high-frequency sound waves are transmitted into the body through a handheld probe. The returning echoes are converted into real-time images displayed on a screen. Ultrasound does not use radiation.
Ultrasound scans during pregnancy are used to:
Scans may be performed abdominally, using a probe held against the abdomen, or transvaginally, using a small probe placed internally. The method used depends on gestational age, clinical indication and the quality of images achievable.
Types of Pregnancy Scans
There are several distinct pregnancy scan names used throughout antenatal care in the UK. Not every scan is offered to every pregnant person. Some are part of the routine NHS schedule; others are only recommended in specific clinical circumstances.
Early Pregnancy Viability Scan
An early pregnancy viability scan, sometimes called an early reassurance scan, may be performed before the routine dating scan. It is typically offered between approximately 6 and 10 weeks of pregnancy. Its primary purpose is to confirm that the pregnancy is located within the uterus, to detect a fetal heartbeat and to identify whether more than one embryo is present.
This type of scan is not routinely offered through NHS antenatal care for all pregnancies. It may be recommended following symptoms such as early pregnancy bleeding or pain, or for those with a history of ectopic pregnancy or recurrent miscarriage.
Dating Scan
The dating scan is one of the most recognised pregnancy scan names in the UK. It is typically performed between 10 and 14 weeks of pregnancy, with 11 to 13 weeks plus six days being the ideal window. Its primary purpose is to estimate gestational age accurately by measuring the length of the baby from crown to rump — a measurement known as crown-rump length (CRL).
The dating scan helps to establish or confirm an estimated due date and determines whether the pregnancy is single or multiple. Where the nuchal translucency screening is being performed, it is usually combined with the dating scan during the same appointment.
Nuchal Translucency Scan
The nuchal translucency scan measures the fluid-filled space at the back of the baby's neck, known as the nuchal translucency. An increased measurement can be associated with a higher chance of certain chromosomal conditions, including Down's syndrome (trisomy 21), Edwards' syndrome (trisomy 18) and Patau's syndrome (trisomy 13).
This scan is performed between 11 weeks and 13 weeks plus six days. In NHS antenatal care in England, the nuchal translucency measurement is combined with a blood test measuring specific pregnancy hormones — this combined screening approach provides a more accurate individual risk estimate than the ultrasound measurement alone.
It is important to understand that the nuchal translucency scan is a screening assessment, not a diagnostic test. A higher-chance result indicates an increased probability of a chromosomal condition; it does not confirm a diagnosis. Further diagnostic testing, such as non-invasive prenatal testing (NIPT) or invasive testing through amniocentesis or chorionic villus sampling (CVS), may be discussed with a healthcare professional.
Anomaly Scan
The anomaly scan is the routine second-trimester scan offered through NHS antenatal care. It is also widely known as the 20-week scan or the mid-pregnancy scan. It is typically performed between 18 and 21 weeks of pregnancy.
The anomaly scan assesses the physical development of the baby in considerable detail. It examines:
The purpose of the anomaly scan is to identify structural differences or abnormalities that may affect the baby's health. It is important to note that not all conditions can be detected by ultrasound, and the quality of imaging can be affected by the baby's position, body habitus and equipment.
If a satisfactory view of certain structures cannot be obtained, a repeat scan may be offered.
Growth Scan
Growth scans are ultrasound examinations used to assess fetal development during the second half of pregnancy, most commonly from around 24 to 28 weeks onwards. They measure the baby's size, including head circumference, abdominal circumference and femur length, and compare these measurements with expected ranges for gestational age.
Growth scans may also assess amniotic fluid levels and placental position. They are not routinely offered to everyone through NHS care but may be recommended when there are concerns about whether the baby is growing appropriately, when the placenta is positioned low or in other clinically indicated circumstances.
Doppler Ultrasound Scan
A Doppler ultrasound scan assesses blood flow through vessels in the placenta, the umbilical cord and sometimes within the fetal brain. This type of scan is used alongside growth assessments and is not a routine examination for all pregnancies.
Doppler assessment may be recommended when fetal growth measurements give cause for concern, or in pregnancies where placental function is being monitored. It helps clinicians understand how effectively nutrients and oxygen are being delivered to the baby.
Cervical Length Scan
A cervical length scan is a targeted transvaginal ultrasound examination that measures the length of the cervix during pregnancy. A shortened cervix is associated with an increased risk of preterm birth.
This scan is not routinely offered to all pregnant people. It may be considered for those with a history of preterm labour, late miscarriage or previous cervical procedures. It is typically performed in the second trimester, commonly around 16 to 24 weeks.
Fetal Echocardiogram
A fetal echocardiogram is a detailed ultrasound examination of the baby's heart. It is distinct from the cardiac views assessed during the standard anomaly scan and provides a much more comprehensive evaluation of cardiac structure and function.
A fetal echocardiogram may be recommended when the anomaly scan raises questions about the heart, when there is a family history of congenital heart conditions, or when other clinical factors indicate that closer cardiac assessment is warranted. It is typically performed between approximately 18 and 24 weeks and is conducted by a specialist.
3D and 4D Pregnancy Scans
A 3D pregnancy scan produces three-dimensional still images of the baby, while a 4D scan adds a live motion element, allowing movement to be observed in real time. These are not standard clinical examinations and are not part of the NHS antenatal care pathway.
3D and 4D scans are primarily offered as elective, non-diagnostic imaging experiences, often through private providers. They are not intended to replace clinical antenatal ultrasound assessments.
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Pregnancy Scan Names and Weeks: A Chronological Guide
The table below provides an overview of common pregnancy scan names, their approximate timing and their principal purpose. Timing may vary depending on individual clinical circumstances, local NHS policies and whether scans are carried out through the NHS or privately.
| Scan Name | Approximate Timing | Main Purpose |
|---|---|---|
| Early pregnancy viability scan | 6–10 weeks | Confirm intrauterine pregnancy, detect heartbeat, identify multiple pregnancy |
| Dating scan (combined with nuchal translucency screening) | 10–14 weeks (ideally 11–13+6 weeks) | Estimate gestational age, establish due date, begin chromosomal screening |
| Nuchal translucency scan | 11–13+6 weeks | Measure nuchal fluid, assess chromosomal condition chance as part of combined screening |
| Anomaly scan (20-week scan) | 18–21 weeks | Detailed fetal anatomy assessment and structural screening |
| Cervical length scan | Approximately 16–24 weeks (if indicated) | Assess preterm birth risk |
| Growth scan | From approximately 24–28 weeks (if indicated) | Monitor fetal size, amniotic fluid levels and placental position |
| Doppler ultrasound | Third trimester or as indicated | Assess placental and umbilical blood flow |
| Fetal echocardiogram | 18–24 weeks (if indicated) | Detailed fetal cardiac assessment |
| 3D or 4D scan | Variable | Elective imaging; not a clinical diagnostic examination |
The NHS Pregnancy Scan Schedule
In England, the NHS routinely offers two ultrasound scans during a healthy, low-risk pregnancy:
1. The dating scan, typically around 8 to 14 weeks (usually 10–14 weeks in practice, with the optimal window being 11 to 13 weeks plus six days when combined screening is being offered).
2. The 20-week anomaly scan, typically offered between 18 and 21 weeks.
These two scans form the foundation of the routine NHS pregnancy ultrasound schedule. Additional scans are offered only when there is a clinical indication. The NHS also offers combined first-trimester screening for chromosomal conditions alongside the dating scan, which includes the nuchal translucency ultrasound measurement and a maternal blood test.
Provision can differ across the four nations of the UK, and the scan schedule offered to an individual may vary depending on pregnancy history, risk factors and clinical findings.
What Happens During a Pregnancy Scan?
For abdominal ultrasound scans, you will typically be asked to lie on an examination couch. A gel is applied to the abdomen to improve sound wave transmission, and the sonographer moves a handheld probe over the skin to capture images.
For transvaginal scans, a slim probe is gently introduced internally. This may be recommended in early pregnancy to obtain clearer images when abdominal scanning does not provide sufficient detail.
Depending on gestational age and the type of scan, you may be asked to arrive with a full bladder, as this can improve image quality in early pregnancy. For later scans, this is not usually required.
After the scan, the sonographer or reporting clinician will explain the findings. If additional scans or further assessment are recommended, your midwife, GP or obstetric team will discuss the next steps with you.
When Might Additional Scans Be Recommended?
Beyond the two routine NHS scans, additional ultrasound examinations may be recommended for a variety of clinical reasons, including:
Additional scans are tailored to individual circumstances. The recommendation to have more frequent monitoring does not necessarily indicate a serious complication, but it does allow healthcare teams to gather more information and provide appropriate care.
Screening Versus Diagnostic Assessment: An Important Distinction
Several pregnancy scans, particularly the nuchal translucency scan and the anomaly scan, are described as screening examinations. Screening assessments estimate the likelihood of a condition being present and identify pregnancies that may benefit from further investigation. They do not confirm or rule out a diagnosis.
A diagnostic test, such as amniocentesis or CVS, provides a definitive chromosomal result by analysing fetal cells. These tests carry a small risk of pregnancy loss and are typically offered when screening results indicate a higher chance of a chromosomal condition, or when ultrasound findings warrant further investigation.
If you receive a higher-chance screening result or if concerns are identified on ultrasound, your midwife or obstetric team will explain your options and support you in making an informed decision about further testing.
Frequently Asked Questions
What is the pregnancy scan name for the first routine NHS ultrasound?
The first routine NHS ultrasound is called the dating scan. It is typically performed between 10 and 14 weeks of pregnancy and is used to estimate gestational age and establish an estimated due date.
What are the different pregnancy scan names used in the UK?
The main pregnancy scan names include the early viability scan, dating scan, nuchal translucency scan, anomaly scan (20-week scan), growth scan, Doppler ultrasound, cervical length scan, fetal echocardiogram, and 3D or 4D scans.
What is the name of the scan at 20 weeks pregnant?
The scan performed at around 20 weeks is called the anomaly scan or mid-pregnancy scan. It is a detailed examination of the baby's anatomy and is routinely offered through NHS antenatal care between 18 and 21 weeks.
What scan is typically carried out at 21 weeks pregnant?
The anomaly scan is usually performed between 18 and 21 weeks. If your scan is scheduled at 21 weeks, it is likely to be this same mid-pregnancy anatomy assessment.
What is a nuchal translucency scan and what does it measure?
A nuchal translucency scan measures the fluid at the back of the baby's neck between 11 and 13 weeks plus six days. Combined with a blood test, it helps estimate the chance of chromosomal conditions such as Down's syndrome. It is a screening test, not a diagnostic one.
How many scans does the NHS routinely offer during pregnancy?
The NHS in England routinely offers two ultrasound scans during a straightforward pregnancy: the dating scan and the 20-week anomaly scan. Additional scans may be offered if there is a clinical reason to do so.
What is a Doppler scan during pregnancy used for?
A Doppler ultrasound scan assesses blood flow through the umbilical cord and placenta. It is not a routine scan for all pregnancies and is typically used to monitor fetal wellbeing when there are concerns about growth or placental function.
What is a fetal echocardiogram and when is it performed?
A fetal echocardiogram is a detailed ultrasound examination of the baby's heart, usually performed between approximately 18 and 24 weeks. It may be recommended when routine scanning raises questions about the cardiac structure, or when there is a family history of heart conditions.
What is the difference between 3D and 4D pregnancy scans?
A 3D scan produces three-dimensional still images of the baby. A 4D scan adds real-time movement to those three-dimensional images. Neither is a routine clinical assessment; both are typically offered as elective, non-diagnostic experiences through private providers.
What is an early pregnancy viability scan?
An early pregnancy viability scan, performed around 6 to 10 weeks, is used to confirm that the pregnancy is located within the uterus, detect a fetal heartbeat and identify whether there is more than one baby. It is not part of the standard NHS schedule for all pregnancies.
What is a cervical length scan and why might it be recommended?
A cervical length scan is a transvaginal ultrasound that measures the length of the cervix to assess the risk of preterm birth. It may be recommended for people with a history of late miscarriage, preterm labour or previous cervical procedures, usually between 16 and 24 weeks.
Can ultrasound scans detect all fetal conditions?
No. While ultrasound scanning is a valuable tool in antenatal care, it cannot guarantee detection of all fetal conditions or structural differences. The quality of images can be affected by factors such as the baby's position, amniotic fluid levels and equipment. If the sonographer cannot obtain adequate views, a repeat scan may be recommended.
References
This article is intended for general educational purposes only. It does not constitute medical advice and should not replace guidance from your midwife, GP or obstetric team. If you have questions about your pregnancy or scan results, please speak with a qualified healthcare professional.