Pregnancy is a journey filled with excitement, regular check-ups, and important decisions about your baby’s health. Among the different prenatal examinations, the anomaly scan is one of the key ultrasound examinations performed during the second trimester. It provides a detailed look at the baby’s physical development and can help healthcare professionals identify signs of certain structural conditions at a stage when further evaluation and care can be planned.
The anomaly scan, often called the 20-week scan or mid-pregnancy scan, is generally performed around 18–21 weeks of pregnancy, although the exact timing can vary according to clinical circumstances and local protocols.
For expectant parents, understanding why the anomaly scan is recommended, what it examines, and what its results mean can make the pregnancy journey more informed and less stressful.
At Iris Diagnostic, patients can discuss pregnancy ultrasound requirements with qualified healthcare professionals and understand which scan is appropriate for their stage of pregnancy.
What Is an Anomaly Scan?
An anomaly scan is a detailed ultrasound examination performed during pregnancy to assess the baby’s anatomy and development.
Unlike an early pregnancy scan that primarily focuses on dating the pregnancy, fetal development, or the number of babies, the anomaly scan provides a more detailed assessment of several fetal structures.
During the anomaly scan, the sonographer examines different parts of the baby’s body and looks for signs of certain physical or structural abnormalities. The scan can also assess fetal growth and the location of the placenta.
Ultrasound uses sound waves to create images of the baby inside the uterus. It is a non-invasive examination and does not involve radiation.
Because the anomaly scan is a screening examination, it is important to understand that it cannot identify every possible health condition. A result that appears normal also cannot guarantee that a baby will have no health problems after birth.
When Should You Have an Anomaly Scan?
The anomaly scan is commonly scheduled during the second trimester.
Many pregnancy care programmes offer the detailed 20-week scan between 18 and 21 weeks, while some clinical guidelines and services use a broader window.
Your doctor may recommend the timing based on:
- Your gestational age
- Your previous scan results
- Your pregnancy history
- Your baby’s position
- Your medical or obstetric history
- Whether additional monitoring is required
It is therefore important not to select the timing of an anomaly scan solely based on information found online. Your obstetrician or healthcare provider can advise you about the appropriate timing.
If you’re approaching the second trimester and haven’t discussed your anomaly scan yet, speak with your pregnancy-care provider about when it should be scheduled.
Why Is the Anomaly Scan Important?
The main purpose of an anomaly scan is to examine fetal anatomy in detail and look for signs of certain physical conditions.
According to NHS pregnancy screening information, the 20-week screening scan looks for signs of several conditions, including anencephaly, open spina bifida, cleft lip and palate, diaphragmatic hernia, gastroschisis, exomphalos, serious cardiac abnormalities, bilateral renal agenesis, severe skeletal dysplasia, Edwards syndrome and Patau syndrome.
This makes the anomaly scan an important part of antenatal screening.
Early identification of a suspected condition can give the healthcare team an opportunity to recommend additional investigations, specialist consultations, monitoring or appropriate pregnancy and delivery planning when needed.
The purpose isn’t to create unnecessary worry. Instead, the anomaly scan provides valuable information about your baby’s development so that your healthcare team can make informed decisions if something requires closer evaluation.
What Does an Anomaly Scan Check?
A detailed anomaly scan generally involves examining multiple areas of the baby’s body.
1. Baby’s Brain
The sonographer assesses the fetal brain and looks at its developing structures.
The second-trimester ultrasound provides an opportunity to visualize many important brain structures and identify signs of major developmental abnormalities.
2. Baby’s Spine
The spine is carefully examined during the anomaly scan.
The scan can help identify certain structural abnormalities affecting the spine, including signs associated with open spina bifida.
3. Baby’s Heart
The fetal heart is an important part of the anomaly scan.
The examination includes assessment of the heart’s appearance and selected views that can help identify signs of serious cardiac abnormalities. However, not every heart condition can be detected through routine ultrasound screening.
4. Baby’s Face
The face is examined for visible structural features, including signs that may suggest conditions such as cleft lip.
5. Abdomen
The sonographer assesses the baby’s abdomen and relevant internal structures.
This can help identify signs of certain abdominal or gastrointestinal abnormalities.
6. Kidneys and Bladder
The kidneys and bladder are also assessed as part of the fetal anatomy examination.
Certain significant abnormalities affecting the urinary system may be visible during the anomaly scan.
7. Bones and Limbs
The sonographer evaluates fetal bones and limbs and looks at their development and appearance.
8. Placenta
The position of the placenta is also assessed during the scan.
Can an Anomaly Scan Detect Problems Early?
Yes, an anomaly scan can identify signs of certain structural or developmental conditions during the second trimester.
This is one of the main reasons the anomaly scan is included in routine antenatal screening programmes.
Finding a suspected issue during pregnancy can allow doctors to arrange additional assessments or specialist consultations where appropriate. Depending on the finding, further ultrasound examinations or other tests may be recommended.
However, the word screening is important.
An anomaly scan does not diagnose every possible condition, and some abnormalities may not be visible on ultrasound. Even when the scan appears normal, it cannot guarantee that the baby will have no health problems.
What Happens During an Anomaly Scan?
The procedure is generally straightforward.
During an anomaly scan, you usually lie on an examination bed while the sonographer applies ultrasound gel to your abdomen. A handheld ultrasound probe is then moved across the abdomen to obtain images of the baby.
The sonographer takes multiple measurements and images while examining different fetal structures.
Depending on the baby’s position and the quality of the available images, the examination may sometimes take longer or require another appointment to complete all necessary views.
You may see your baby’s images on the screen during the anomaly scan, but remember that the sonographer’s priority is completing the medical examination accurately.
Is an Anomaly Scan Safe?
Ultrasound scans are widely used during pregnancy. They use sound waves rather than ionizing radiation.
The NHS states that pregnancy ultrasound scans have no known side effects for mothers or babies when used appropriately.
Nevertheless, pregnancy scans should be performed for appropriate clinical purposes and interpreted by trained professionals.
If you have concerns about the safety, frequency or timing of your anomaly scan, discuss them with your obstetrician or healthcare provider.
What If the Anomaly Scan Finds Something?
An abnormal or unclear finding does not automatically mean that your baby has a serious health problem.
Sometimes a particular structure may be difficult to visualize because of:
- The baby’s position
- Movement during the examination
- Maternal body factors
- The gestational age
- Image quality
- The position of the placenta
In some situations, the healthcare team may recommend repeating the anomaly scan or performing another ultrasound to obtain better images.
If a potential abnormality is identified, you may be referred for further assessment or specialist testing. NHS guidance notes that additional testing may be offered when a scan suggests that a baby may have a condition.
Therefore, an unexpected finding should be discussed with your doctor rather than interpreted independently from an ultrasound report.
What If the Anomaly Scan Is Normal?
A normal anomaly scan is reassuring because the examination has not identified the specific abnormalities being screened for.
However, it is important to understand what a normal screening result means.
The anomaly scan does not examine every possible genetic, developmental or health condition. Some conditions can develop later in pregnancy, while others may not be visible on ultrasound.
That is why continuing regular antenatal appointments remains important even after a normal anomaly scan.
Your doctor may recommend additional scans or monitoring depending on your pregnancy and individual circumstances.
Anomaly Scan vs Other Pregnancy Scans
Pregnancy involves different types of ultrasound examinations, and each has a different purpose.
Dating Scan
An early pregnancy scan can help establish gestational age and estimate the expected due date. It may also assess whether there is more than one baby and evaluate early development.
NT Scan
A nuchal translucency scan is performed during the first trimester and may form part of screening for certain chromosomal conditions when combined with other screening methods.
Anomaly Scan
The anomaly scan is performed later in pregnancy and provides a detailed assessment of fetal anatomy.
Growth Scan
A growth scan may be recommended later in pregnancy when the healthcare team needs to assess fetal growth or wellbeing.
Each scan has a different purpose. Therefore, an anomaly scan should not be considered a replacement for other pregnancy examinations recommended by your doctor.
How Should You Prepare for an Anomaly Scan?
Preparation requirements can vary between diagnostic centres.
Before your anomaly scan, ask the diagnostic centre whether you need a full bladder or any other preparation.
Some facilities may provide specific instructions depending on the type of ultrasound being performed.
It can also be helpful to:
- Arrive a little early
- Carry your previous ultrasound reports
- Bring your pregnancy records if advised
- Wear comfortable clothing
- Follow the instructions provided by your diagnostic centre
- Tell the sonographer about relevant pregnancy concerns
If you are having an anomaly scan at a diagnostic centre, following the centre’s preparation instructions can help make the appointment smoother.
Why Choose a Professional Diagnostic Centre for an Anomaly Scan?
The quality of an ultrasound examination depends on several factors, including the equipment, the expertise of the person performing the examination, the baby’s position and the clinical information available.
Choosing an established diagnostic centre can help ensure that your pregnancy imaging is performed in an appropriate clinical setting.
At Iris Diagnostic, patients can enquire about pregnancy ultrasound services and discuss the appropriate scan with the healthcare team.
If your doctor has recommended an anomaly scan, it is useful to carry your previous reports and prescription so the imaging team has relevant clinical information.
Don’t Delay Your Anomaly Scan Without Discussing It With Your Doctor
Pregnancy appointments often become busy, especially during the second trimester. But recommended screening should not be casually postponed.
The anomaly scan is generally scheduled within a specific stage of pregnancy because fetal structures are sufficiently developed to allow detailed assessment.
If you are approaching the recommended period for your anomaly scan, contact your obstetrician or diagnostic centre to understand when you should have the examination.
If you have already missed the expected window, don’t panic. Speak with your doctor as soon as possible because the appropriate next step depends on your gestational age and individual circumstances.
Why the Second Trimester Is an Important Period for Fetal Assessment
The second trimester is an important stage of pregnancy because many fetal structures have developed sufficiently to allow detailed ultrasound assessment.
During this period, healthcare professionals can examine several anatomical structures and evaluate aspects of fetal development. The examination can also provide information about the placenta and other pregnancy-related findings.
However, every pregnancy is different. The timing and type of imaging recommended by a doctor may depend on gestational age, previous findings, pregnancy history and other clinical factors.
This is why parents should follow the schedule recommended by their obstetrician instead of relying only on a general pregnancy calendar.
If you are unsure whether you are due for a detailed pregnancy ultrasound, speak with your doctor or contact a diagnostic centre such as Iris Diagnostic to understand the available appointment options.
What Can Affect the Quality of Pregnancy Ultrasound Images?
Many parents expect the examination to produce clear images immediately. In reality, obtaining detailed images can sometimes take time.
One of the most common factors is the baby’s position.
A baby may be facing away from the ultrasound probe, have its hands covering the face, or be positioned in a way that makes certain structures difficult to visualize. In such situations, the sonographer may ask you to change position or take a short break.
Other factors can also influence image quality, including:
- Gestational age
- Baby’s movement
- Placental position
- Maternal body characteristics
- Amount of amniotic fluid
- Fetal position
- Equipment and imaging conditions
If every required image cannot be obtained during the first appointment, another examination may sometimes be recommended.
This does not automatically indicate that there is a problem with the baby.
It may simply mean that the healthcare professional needs clearer views before completing the assessment.
What If the Baby Is Not Cooperating During the Scan?
This is a common concern among expectant parents.
Babies do not follow instructions during an ultrasound examination. Their movements and position are completely independent of the appointment schedule.
If the baby’s position makes certain structures difficult to examine, the sonographer may wait for the baby to move or suggest that you change your position.
Sometimes walking around briefly can help change fetal positioning. However, any instructions should come from the healthcare professional performing the examination.
If adequate images still cannot be obtained, a repeat appointment may be recommended.
Parents should not assume that a repeat examination means something is wrong. In many cases, it is simply necessary to obtain better images.
Should You Bring Previous Pregnancy Reports?
Yes, when possible, carrying previous pregnancy-related reports can be useful.
Previous ultrasound reports may provide important background information about:
- Gestational age
- Earlier ultrasound findings
- Previous measurements
- Placental location
- Pregnancy history
- Recommendations for follow-up
- Previous concerns identified by your doctor
Providing relevant medical information helps the imaging team understand the clinical context of the examination.
At Iris Diagnostic, patients can carry their previous reports and doctor’s prescription when attending a pregnancy imaging appointment.
What Questions Should You Ask Before the Examination?
Pregnancy can involve a large amount of medical information, and it is completely reasonable to have questions.
Before attending your appointment, you may want to ask:
Do I need any preparation?
Preparation requirements can vary depending on the examination and stage of pregnancy. Ask the diagnostic centre whether you need to follow any specific instructions.
How long will the examination take?
The duration can vary depending on fetal position, image quality and the number of structures that need to be assessed.
Should I bring previous reports?
Ask whether previous ultrasound reports or prescriptions are required.
What happens if some images cannot be obtained?
Your healthcare provider can explain whether you may need a repeat examination.
When will I receive the report?
Ask the centre about its reporting process and when you can expect the results.
Having these questions ready can make your appointment easier and reduce uncertainty.
Understanding the Difference Between Screening and Diagnosis
One of the most important things parents should understand is the difference between screening and diagnosis.
A screening examination looks for signs that may indicate a potential problem. It does not necessarily confirm that a medical condition is present.
If an ultrasound identifies something that requires further evaluation, the doctor may recommend additional tests or specialist assessment.
For example, a particular ultrasound finding may require a more detailed scan, follow-up imaging or consultation with a specialist.
Therefore, parents should avoid interpreting a single ultrasound finding independently.
A qualified healthcare professional should explain the result in the context of the pregnancy.
What Happens After an Unexpected Finding?
Receiving a report that mentions an unexpected finding can naturally cause anxiety.
However, an abnormal or uncertain ultrasound finding does not always mean that the baby has a serious condition.
There can be several reasons for an unusual or unclear observation. Sometimes the finding may require additional imaging simply because the initial images were incomplete.
Depending on the situation, your doctor may recommend:
- Repeat ultrasound
- More detailed fetal imaging
- Specialist consultation
- Additional screening
- Diagnostic testing
- Regular pregnancy monitoring
The appropriate next step depends on the specific finding and your individual pregnancy.
Parents should therefore discuss the report with their obstetrician rather than searching for a diagnosis based on individual medical terms.
Why Follow-Up Matters
If your doctor recommends another examination, attending the follow-up is important.
Pregnancy is constantly changing, and some findings need to be monitored over time.
A follow-up scan may allow healthcare professionals to:
- Reassess a previously unclear structure
- Monitor fetal growth
- Evaluate a suspected finding
- Obtain additional images
- Check a specific anatomical area
- Assess changes over time
Not every follow-up examination means that a serious problem has been identified.
Sometimes it is simply part of careful pregnancy management.
Can Everything Be Seen on One Ultrasound?
No.
This is an important expectation for parents.
Even detailed fetal imaging has limitations. Some abnormalities may not be visible during a routine ultrasound, while others may develop or become apparent later in pregnancy.
Image quality can also vary depending on fetal position and other factors.
Therefore, a normal examination is reassuring but does not guarantee that every possible health condition has been ruled out.
This is one reason why regular prenatal care remains important throughout pregnancy.
Your doctor may recommend additional scans or tests depending on your medical history and pregnancy progression.
The Importance of Experienced Ultrasound Professionals
Pregnancy imaging requires careful assessment of multiple fetal structures.
The quality of the examination depends on factors such as appropriate equipment, image quality, operator experience and the clinical information available.
A trained professional evaluates the images and prepares the findings for medical interpretation.
Parents should remember that an ultrasound appointment is not simply a photography session. The primary purpose is medical assessment.
At Iris Diagnostic, patients can discuss pregnancy ultrasound requirements with the centre’s healthcare team and understand the process before their appointment.
How to Make Your Appointment More Comfortable
A few simple steps can make your pregnancy ultrasound appointment easier.
Wear Comfortable Clothing
Choose clothing that allows easy access to the abdomen.
Arrive on Time
Arriving early gives you enough time for registration and paperwork without unnecessary stress.
Carry Relevant Documents
Bring your doctor’s prescription, previous ultrasound reports and other relevant medical documents if requested.
Follow Preparation Instructions
If the diagnostic centre provides specific preparation instructions, follow them carefully.
Keep Questions Ready
Write down any concerns you want to discuss so you do not forget them during the appointment.
Avoid Comparing Your Experience With Others
Every pregnancy is different.
One person’s examination may take less time than another person’s. One baby may remain still while another moves continuously.
Differences in scan duration or image quality do not automatically indicate a problem.
What Information Can Parents Expect in the Report?
A pregnancy ultrasound report can contain several technical terms.
Depending on the examination, the report may include information about:
- Fetal measurements
- Gestational age
- Fetal position
- Anatomical structures
- Placental location
- Amniotic fluid
- Fetal heart activity
- Growth-related observations
- Any findings requiring follow-up
Medical terminology can sometimes be difficult to understand.
If you see a term you do not recognize, ask your doctor or the reporting specialist for an explanation.
Avoid assuming that an unfamiliar medical word automatically indicates an abnormality.
Why Online Searches Should Not Replace Medical Advice
Searching for health information online can be useful for learning basic concepts, but it can also create unnecessary anxiety.
A medical term in an ultrasound report can have different implications depending on the complete clinical picture.
For example, a measurement may appear outside a general reference range but still require interpretation according to gestational age and other findings.
Similarly, an isolated ultrasound observation does not necessarily establish a diagnosis.
This is why your obstetrician should interpret pregnancy imaging results in context.
Use reliable medical resources to understand general information, but rely on your healthcare provider for personal medical decisions.
What If You Miss the Recommended Appointment?
If you have missed the suggested appointment period, do not immediately assume that something is wrong.
Contact your obstetrician as soon as possible and explain how many weeks pregnant you are.
Your doctor can determine the appropriate next step based on your current gestational age and pregnancy history.
Depending on the circumstances, another examination may still provide useful information.
The most important thing is to avoid delaying communication with your healthcare provider because of uncertainty.
Pregnancy Ultrasound at Iris Diagnostic
For expectant parents, choosing a diagnostic centre is an important part of planning pregnancy-related investigations.
Iris Diagnostic provides diagnostic imaging services where patients can enquire about pregnancy ultrasound examinations according to their doctor’s recommendations.
Before booking, patients can confirm:
- Available appointment timings
- Preparation requirements
- Required documents
- Reporting process
- Whether a doctor’s prescription is needed
- Any specific instructions for the examination
If your doctor has advised a detailed fetal ultrasound, contacting Iris Diagnostic in advance can help you understand the appointment process.
When Should You Contact Your Doctor?
You should follow the prenatal appointment schedule provided by your obstetrician.
Contact your doctor if you have questions about:
- The timing of your next scan
- Previous ultrasound findings
- An unclear report
- A recommendation for additional imaging
- Changes in your pregnancy that concern you
- Whether another test is required
Do not wait for the next routine appointment if your doctor has specifically advised earlier evaluation.
A Normal Report Is Only One Part of Prenatal Care
It can be tempting to think that one normal ultrasound means that all pregnancy-related concerns are finished.
Prenatal care does not work that way.
Pregnancy involves continuous changes, and different appointments assess different aspects of maternal and fetal health.
Your doctor may recommend blood tests, blood pressure monitoring, additional ultrasounds, screening tests and other examinations at different stages.
Each serves a particular purpose.
Therefore, even after reassuring ultrasound results, continue following your doctor’s recommended pregnancy-care schedule.
What Parents Should Remember
The middle months of pregnancy can bring excitement as well as plenty of questions.
A detailed ultrasound can provide valuable information about fetal development and help healthcare professionals identify signs that may require further evaluation.
However, it is equally important to understand the limitations of ultrasound.
No single examination can detect every possible condition.
The most useful approach is to combine appropriate prenatal screening with regular medical care and professional interpretation of results.
If your doctor has recommended a pregnancy ultrasound, make sure you understand when it should be performed and whether any preparation is required.
Frequently Asked Questions About Anomaly Scan
1. What is an anomaly scan?
An anomaly scan is a detailed second-trimester ultrasound that examines the baby’s anatomy and development and screens for signs of certain structural conditions.
2. At what week is an anomaly scan done?
The anomaly scan is commonly performed around 18–21 weeks of pregnancy, although the exact timing can vary depending on the healthcare provider and clinical circumstances.
3. Can an anomaly scan detect birth defects?
An anomaly scan can detect signs of some structural abnormalities, but it cannot detect every birth defect or health condition.
4. Is an anomaly scan painful?
An anomaly scan is generally painless. Some women may experience mild discomfort when the ultrasound probe is pressed against the abdomen to obtain clearer images.
5. Is an anomaly scan the same as a 20-week scan?
Yes. The terms anomaly scan, 20-week scan, anatomy scan and mid-pregnancy scan are commonly used for this detailed second-trimester ultrasound.
6. What organs are checked during an anomaly scan?
The examination can include assessment of the baby’s brain, spine, heart, face, abdomen, kidneys, limbs and other anatomical structures, along with fetal growth and placenta assessment.
7. Does a normal anomaly scan guarantee a healthy baby?
No. A normal anomaly scan is reassuring but cannot guarantee that every possible health or developmental condition has been ruled out. Some conditions cannot be detected through routine ultrasound screening.
8. What happens if an anomaly is detected?
Your doctor may recommend additional imaging, specialist consultation or further testing depending on the finding. A suspected finding does not necessarily confirm that a condition is present.
Book Your Pregnancy Scan with Iris Diagnostic
If your doctor has recommended a detailed pregnancy ultrasound, timely screening can help provide valuable information about your baby’s development. Speak with your healthcare provider about the appropriate timing and requirements for your examination.
For pregnancy ultrasound and diagnostic imaging enquiries, Iris Diagnostic is available to assist you with appointment-related information.
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Don’t delay an important pregnancy check-up. Contact Iris Diagnostic today to enquire about your appointment.