Pregnancy is filled with important milestones, and one of the most detailed is the anomaly scan. Also known as a detailed pregnancy scan or mid-pregnancy ultrasound, this examination allows doctors to closely assess your baby’s development and check whether major anatomical structures are developing as expected.
For many parents, the anomaly scan is an exciting experience because it provides a more detailed look at the growing baby. At the same time, it can naturally bring questions: What exactly does the doctor check? Is everything visible on the scan? What happens if something unusual is noticed?
At Iris Diagnostic, detailed pregnancy imaging is performed to provide valuable information about fetal development and support appropriate medical evaluation. While an ultrasound cannot guarantee that every possible condition will be detected, it can help doctors identify many structural findings and determine whether further assessment may be needed.
The anomaly scan is generally performed around the middle of pregnancy, often between 18 and 22 weeks, depending on the pregnancy and the recommendation of the treating doctor. The exact timing may vary based on individual circumstances.
What Is an Anomaly Scan?
An anomaly scan is a detailed ultrasound examination used to evaluate the baby’s anatomy and development during pregnancy. Unlike an early pregnancy ultrasound, which may primarily focus on pregnancy location, fetal heartbeat, gestational age, and other early findings, the detailed scan examines multiple parts of the baby’s body.
During the examination, ultrasound waves create images of the developing fetus. The sonologist or appropriately trained healthcare professional evaluates different anatomical structures and measurements and documents the findings.
The purpose of an anomaly scan is not simply to obtain a picture of the baby. It is a structured examination in which several areas are assessed systematically.
Depending on the pregnancy and clinical circumstances, the scan may examine:
- Baby’s brain and head
- Face and facial structures
- Spine
- Heart and chest
- Abdomen
- Kidneys and bladder
- Arms and legs
- Placenta
- Amniotic fluid
- Fetal growth and measurements
Let’s look at seven important areas doctors commonly assess during a detailed pregnancy ultrasound.
1. Baby’s Brain and Head Development
One of the major areas examined during an anomaly scan is the baby’s head and brain.
The fetal brain undergoes significant development during pregnancy, so doctors evaluate several structures visible on ultrasound. They may assess the shape and size of the head and examine structures within the brain that can be visualized during the scan.
The examination may include assessment of:
- Head shape and size
- Ventricular structures
- Midline structures
- Cerebellum
- Posterior fossa
- Other visible brain anatomy
Measurements may also be taken to evaluate fetal growth. These measurements are compared with expected ranges for the baby’s gestational age.
It is important to understand that ultrasound has technical limitations. The visibility of certain structures can depend on fetal position, maternal body characteristics, gestational age, and equipment quality.
If the baby’s position makes a particular structure difficult to assess, the healthcare professional may recommend additional imaging or a repeat examination.
A detailed anomaly scan therefore provides an important opportunity to assess fetal brain development while recognizing that ultrasound cannot identify every neurological or developmental condition.
2. The Face and Facial Structures
The baby’s face is another area that may be evaluated during the anomaly scan.
Doctors look at facial structures that can be visualized using ultrasound. Depending on fetal position and image quality, the examination may include assessment of the facial profile, upper lip, nasal region, and other visible structures.
One reason this assessment is important is that certain structural differences may sometimes be detected during a detailed ultrasound.
However, parents should remember that fetal position can make facial imaging challenging. If the baby is facing away from the ultrasound probe or has their hands near the face, obtaining clear images may take additional time.
This is one reason why an anomaly scan can sometimes take longer than parents expect.
A detailed scan is not simply about taking one photograph. The healthcare professional may need to obtain multiple views from different angles to evaluate the required anatomy.
3. The Baby’s Spine
The spine is another important structure assessed during an anomaly scan.
Doctors examine the alignment and appearance of the fetal spine along its length. Different ultrasound views can be used to evaluate the vertebral column and surrounding structures.
The sonologist may assess:
- The overall spinal alignment
- The vertebral column
- The skin covering over the spine
- Associated structures that can be visualized
Spinal assessment forms an important component of the detailed fetal anatomical examination.
However, just as with other parts of the anomaly scan, visibility can vary. The baby’s position and movement may affect the quality of images obtained.
If the required views cannot be obtained adequately, the healthcare professional may suggest waiting for the baby to move or returning for additional imaging.
This does not automatically mean that there is a problem. Sometimes the reason for additional imaging is simply that a particular anatomical view was not clear enough.
4. The Baby’s Heart
The fetal heart receives considerable attention during a detailed pregnancy scan.
The heart is a complex organ, and ultrasound can provide important information about its structure and movement. During the anomaly scan, healthcare professionals may assess the baby’s heartbeat, heart position, and several anatomical views of the heart.
Depending on the examination, doctors may evaluate:
- Heart rate
- Heart position
- Four-chamber view
- Outflow tracts
- Major vessels that can be visualized
- Overall cardiac appearance
The four-chamber view is an important component of fetal cardiac assessment. Additional views may be obtained when appropriate.
Because the fetal heart is small and constantly moving, obtaining all required images can sometimes be technically challenging.
If the initial examination raises a concern or if the heart cannot be assessed adequately, the doctor may recommend a specialized fetal echocardiogram or another appropriate evaluation.
Parents should also understand that a normal anomaly scan does not completely rule out every congenital heart condition. Some cardiac abnormalities may be subtle or develop in ways that cannot be detected during a routine ultrasound.
5. Abdomen, Stomach, Kidneys and Bladder
The baby’s abdominal structures are another key part of the anomaly scan.
Doctors may examine the appearance and position of the stomach, kidneys, bladder, and other abdominal structures that can be visualized.
The presence of a visible stomach and bladder can provide useful information during the scan. The kidneys are also assessed for their appearance and location.
Doctors may look at:
- Stomach position and appearance
- Kidneys
- Bladder
- Abdominal wall
- Umbilical cord insertion
- Other visible abdominal structures
The abdominal wall may also be evaluated for structural abnormalities.
The umbilical cord can be examined as part of the overall fetal and placental assessment. In many pregnancies, the cord contains three vessels, although variations can occur and may require clinical interpretation.
If an unusual finding is identified during an anomaly scan, it does not necessarily mean that the baby has a serious medical condition. Some ultrasound findings may be temporary, isolated, or require additional assessment to understand their significance.
Your obstetrician or fetal medicine specialist can explain what a particular finding means in the context of the entire pregnancy.
6. Arms, Legs and Other Physical Structures
The baby’s limbs are also examined during an anomaly scan.
Doctors assess the development and appearance of the arms and legs and look at structures that can be visualized during the examination.
The scan may include evaluation of:
- Upper limbs
- Lower limbs
- Long bones
- Hands
- Feet
- Movement of the limbs
- General symmetry and appearance
Measurements of certain long bones may also contribute to the assessment of fetal growth.
Parents sometimes expect the ultrasound to show every finger and toe clearly. However, detailed visualization of small structures can depend heavily on fetal position and image quality.
The purpose of the anomaly scan is primarily medical assessment rather than producing a complete photographic record of every part of the baby.
If the baby is moving frequently or positioned in a way that makes a particular limb difficult to assess, the sonologist may need to wait for a better position.
7. Growth, Placenta and Amniotic Fluid
The final major area involves looking at the overall pregnancy environment, including fetal growth, placenta, and amniotic fluid.
During the anomaly scan, doctors take specific fetal measurements. These may include measurements of the baby’s head, abdomen, and long bones. Together, these measurements help estimate fetal growth and assess whether development appears appropriate for the gestational age.
The placenta is also assessed for its location and appearance. Its position is particularly relevant because placental location can change as pregnancy progresses.
The amount of amniotic fluid is another important consideration. Amniotic fluid surrounds the baby and plays several roles during pregnancy.
Doctors may evaluate whether the amount of fluid appears appropriate and interpret the finding along with the baby’s anatomy, growth, and other clinical information.
The anomaly scan may therefore provide information about both the baby and the surrounding pregnancy environment.
Why Is the Anomaly Scan Important?
The anomaly scan is an important component of routine prenatal care because it provides a structured opportunity to assess fetal anatomy during a stage when many important structures can be visualized.
One of its key purposes is to identify structural abnormalities that may require further investigation or specialist care.
It can also provide reassurance when the examination shows expected development.
However, parents should understand that ultrasound screening has limitations.
A normal anomaly scan does not guarantee that the baby has no medical or developmental condition. Some abnormalities may be too small to detect, may not be visible on ultrasound, or may develop later in pregnancy.
Similarly, an unusual ultrasound finding does not automatically mean that a serious problem is present.
The meaning of a finding depends on several factors, including:
- The exact ultrasound appearance
- Gestational age
- Whether the finding is isolated
- Other ultrasound findings
- Maternal history
- Previous screening results
- Family history
- Clinical assessment
Your doctor can explain the significance of the findings and advise whether additional testing is appropriate.
How Should You Prepare for an Anomaly Scan?
In most cases, there is no complicated preparation required for a detailed pregnancy ultrasound. However, preparation instructions can vary depending on the stage of pregnancy, imaging centre, and specific examination.
Before visiting Iris Diagnostic, follow any preparation instructions provided by your healthcare provider or diagnostic centre.
It can also be helpful to carry previous pregnancy reports and ultrasound records. Having earlier reports available allows the healthcare team to understand the pregnancy history and compare relevant findings where appropriate.
Wear comfortable clothing that allows easy access to the abdomen.
Most importantly, try not to worry if the scan takes longer than expected. A detailed examination may require multiple images and measurements.
What Happens If the Doctor Cannot See Everything Clearly?
This is one of the most common concerns among parents.
Sometimes, the sonologist may not be able to obtain every required image during the first attempt. This can happen because the baby is in an unfavorable position, moving continuously, or facing away from the ultrasound probe.
Maternal factors and technical limitations can also affect image quality.
In such situations, a repeat scan or additional assessment may be recommended.
A request for repeat imaging does not automatically mean that something is wrong.
The goal is to obtain adequate images so that the required structures can be assessed properly.
If the anomaly scan identifies a possible concern, your doctor may explain the finding and recommend an appropriate next step. Depending on the situation, this could involve a repeat ultrasound, targeted scan, fetal echocardiography, blood tests, genetic counselling, or consultation with a fetal medicine specialist.
Understanding Your Anomaly Scan Report
After the examination, you may receive a detailed report containing measurements, observations, and descriptions of different anatomical structures.
Medical terminology can sometimes be difficult to understand.
Instead of relying on isolated phrases in the report, discuss the complete findings with your obstetrician. A single measurement or observation should generally be interpreted in the context of gestational age and the overall examination.
For example, fetal measurements may naturally vary within expected ranges. Similarly, a note stating that a structure was “not well visualized” may simply indicate that a satisfactory image could not be obtained during the examination.
Your doctor can explain whether the finding requires follow-up.
Choosing a Diagnostic Centre for Pregnancy Ultrasound
A detailed pregnancy ultrasound requires careful imaging and systematic evaluation. When choosing a diagnostic centre, parents may consider factors such as qualified professionals, appropriate ultrasound equipment, reporting standards, accessibility, and coordination with their treating doctor.
Iris Diagnostic provides diagnostic imaging services designed to support healthcare evaluation across different stages of pregnancy.
For parents scheduling an anomaly scan, it is useful to ask the diagnostic centre about appointment availability, preparation instructions, required previous reports, and whether any specific referral is needed.
The scan should always be interpreted as part of the mother’s overall prenatal care rather than as an isolated test.
Why a Detailed Examination Takes Time
Many parents expect an ultrasound to be completed quickly. A detailed anomaly scan, however, involves examining numerous anatomical structures and obtaining specific images and measurements.
The healthcare professional may need to capture different views of the baby’s:
- Head and brain
- Face
- Spine
- Heart
- Chest
- Abdomen
- Kidneys and bladder
- Arms and legs
- Placenta
- Umbilical cord
- Amniotic fluid
The baby may move frequently during the examination. Sometimes the baby’s position makes one particular structure difficult to visualize. The sonologist may therefore spend additional time obtaining suitable views.
This is normal and does not necessarily indicate that something is wrong.
What Makes Every Pregnancy Scan Different?
No two pregnancy ultrasounds are exactly the same. Several factors can influence the quality and duration of an anomaly scan.
These may include:
Gestational age: Different structures become easier to visualize at different stages.
Fetal position: A baby facing away from the probe may make certain structures difficult to assess.
Fetal movement: Frequent movement can make it challenging to capture specific images.
Maternal factors: Individual anatomical factors can affect ultrasound visualization.
Equipment and imaging conditions: Image quality can influence how clearly certain structures can be evaluated.
Because of these factors, a scan that takes longer than expected should not automatically be interpreted as a warning sign.
The Importance of Following Up on Recommendations
Sometimes an anomaly scan report may recommend additional imaging. This could happen because a particular structure was not adequately visualized or because the healthcare professional noticed a finding that needs closer evaluation.
Additional testing may include a repeat ultrasound, targeted examination, fetal echocardiography, or consultation with a specialist, depending on the circumstances.
The recommendation should be discussed with your treating doctor rather than interpreted independently.
At Iris Diagnostic, parents can keep their previous reports available so that relevant pregnancy information can be considered during follow-up examinations.
What Else Can Doctors Evaluate During an Anomaly Scan?
The seven major areas discussed in Part 1 represent the core components of a detailed fetal examination, but doctors may also consider several additional observations.
Fetal Position and Presentation
During an anomaly scan, the baby’s position may be documented. The baby can be head-down, breech, transverse, or in another position at the time of the examination.
At the mid-pregnancy stage, fetal position can change frequently. Therefore, the position observed during an anomaly scan is generally not a prediction of the baby’s position at delivery.
The main importance of fetal position during the examination is often related to obtaining appropriate ultrasound views.
For example, if the baby is facing toward the mother’s back, obtaining certain facial or cardiac images may be more difficult.
The sonologist may wait for the baby to move or may use different scanning angles to obtain the required views.
Placental Location and Appearance
The placenta is another important part of pregnancy assessment.
During an anomaly scan, the location of the placenta may be documented. The healthcare professional may note whether it is positioned toward the front, back, side, or upper portion of the uterus.
If the placenta appears close to or covering the cervical opening, your doctor may recommend follow-up imaging later in pregnancy because placental position can change as the uterus grows.
A placental finding should always be interpreted according to gestational age and the overall clinical picture.
Amniotic Fluid Assessment
Amniotic fluid surrounds the baby and provides an important environment for fetal development.
As part of the anomaly scan, the healthcare professional may assess whether the amount of fluid appears appropriate.
Changes in amniotic fluid can sometimes be associated with different maternal or fetal conditions, but an ultrasound observation by itself does not establish a diagnosis.
If the report identifies an abnormal fluid level, the obstetrician may recommend additional monitoring or investigations based on the individual pregnancy.
Umbilical Cord Assessment
The umbilical cord connects the baby to the placenta and plays an essential role in delivering oxygen and nutrients.
During an anomaly scan, the cord may be assessed for its insertion and visible structure. The number of vessels may also be documented.
If a variation is identified, your doctor may consider the finding alongside fetal growth and other ultrasound observations.
It is important not to interpret one isolated ultrasound finding without professional guidance.
Fetal Measurements During the Detailed Scan
One of the important parts of an anomaly scan is taking fetal measurements.
These measurements help healthcare professionals estimate fetal size and assess whether growth appears appropriate for the pregnancy stage.
Common measurements can include:
- Head circumference
- Biparietal diameter
- Abdominal circumference
- Femur length
These measurements are considered together rather than viewed independently.
For example, a baby’s estimated size can vary naturally. The healthcare professional considers the measurements against gestational age and other clinical information.
Estimated fetal weight calculated from ultrasound measurements is also an estimate rather than an exact measurement of the baby’s actual weight.
Parents should therefore avoid comparing one baby’s estimated weight directly with another baby’s scan result without considering gestational age and other factors.
Why Growth Assessment Matters
Growth assessment during an anomaly scan can provide useful information about fetal development.
If measurements appear smaller or larger than expected, your doctor may recommend monitoring or additional scans.
A single measurement does not necessarily indicate a growth problem. Growth assessment often becomes more meaningful when measurements are followed over time.
This is why follow-up scans may sometimes be recommended.
At Iris Diagnostic, keeping previous ultrasound reports can be helpful when your doctor needs to compare findings from different stages of pregnancy.
What If Something Unusual Appears on the Anomaly Scan?
This is one of the biggest concerns parents may have before their examination.
An unusual ultrasound finding does not automatically mean that the baby has a serious condition.
Sometimes an observation may represent:
- A normal variation
- A temporary finding
- An isolated ultrasound marker
- A structure that requires better visualization
- A finding requiring follow-up
- A possible structural abnormality
The next step depends on the specific finding.
Your obstetrician may recommend repeating the anomaly scan, arranging a more specialized ultrasound, conducting additional screening, or consulting a fetal medicine specialist.
The purpose of additional evaluation is to obtain more information and understand the finding accurately.
Parents should avoid drawing conclusions from individual words in an ultrasound report without discussing them with their healthcare provider.
Screening Is Different From Diagnosis
It is important to understand that an anomaly scan is primarily an imaging-based screening examination.
It can identify structural findings that may require further evaluation, but it cannot diagnose every possible medical, genetic, or developmental condition.
Some conditions may not produce visible ultrasound changes. Others may develop later in pregnancy or may be too subtle to detect during the examination.
Therefore, even when the anomaly scan appears normal, routine prenatal care remains important.
Your doctor may recommend additional screening or testing based on your medical history, age, family history, previous test results, or other pregnancy-related factors.
Why Fetal Heart Assessment Is Particularly Important
The fetal heart is one of the most technically challenging areas of a detailed ultrasound.
During an anomaly scan, healthcare professionals may obtain several different views of the fetal heart rather than relying on a single image.
The examination may evaluate:
- Heart position
- Heart rate
- Four chambers
- Outflow tracts
- Major vessels that can be visualized
The baby’s heart is very small at this stage and continues to move throughout the examination.
A clear cardiac assessment can sometimes require patience because the baby may change position repeatedly.
If the healthcare professional cannot obtain adequate views, another scan may be recommended.
In some circumstances, a fetal echocardiogram may be advised for a more detailed cardiac evaluation.
Can Parents See the Baby During the Anomaly Scan?
Yes, parents can often see the baby during the examination, depending on the imaging setup and the position of the ultrasound machine.
Seeing the baby’s movements can be an emotional experience.
However, it is important to remember that the primary purpose of an anomaly scan is medical assessment.
The healthcare professional is concentrating on obtaining specific anatomical views and measurements rather than simply producing attractive images.
Parents may notice periods of silence while the sonologist concentrates on the examination. This does not necessarily mean that something is wrong.
A detailed ultrasound requires concentration because many structures must be assessed systematically.
What Should You Ask After Your Anomaly Scan?
Once the examination is completed, parents may have several questions.
You can ask your healthcare provider:
Was the baby’s anatomy adequately visualized?
Sometimes a structure may not have been clearly seen because of fetal position or technical limitations.
Are the fetal measurements appropriate for the gestational age?
Your doctor can explain the measurements and whether they appear consistent with the pregnancy stage.
Is the placenta in an expected location?
Placental location can be discussed along with whether follow-up is necessary.
Is the amniotic fluid appropriate?
Your doctor can explain whether the fluid assessment is within the expected range.
Is any additional imaging required?
If the anomaly scan was incomplete or a finding needs further evaluation, your doctor can explain the recommended next step.
When should the next pregnancy scan be done?
The timing depends on the individual pregnancy and whether additional monitoring is needed.
How to Prepare Mentally for Your Detailed Pregnancy Scan
Pregnancy scans can create a mixture of excitement and nervousness.
Parents may naturally worry about what the anomaly scan might show. However, going into the appointment with accurate expectations can make the experience easier.
Remember that the scan is designed to provide information. Its purpose is to assess development and identify findings that may need attention.
If the sonologist spends a long time looking at one particular area, it does not automatically mean that a problem has been found.
Likewise, if you are asked to change position, walk around, or return for additional imaging, this can simply be because better images are needed.
The best approach is to wait for the completed report and discuss it with your obstetrician.
Why Choosing the Right Diagnostic Centre Matters
A detailed pregnancy ultrasound requires systematic imaging, appropriate equipment, trained professionals, and accurate reporting.
When planning an anomaly scan, parents may want to consider:
- Availability of appropriate ultrasound services
- Experience of the imaging team
- Quality of equipment
- Clear reporting
- Accessibility
- Coordination with the treating doctor
- Availability of follow-up imaging when recommended
Iris Diagnostic can be considered as part of your diagnostic care planning when your doctor recommends pregnancy imaging.
Before your appointment, confirm the required preparation, appointment timing, documents to bring, and any specific instructions provided by the centre.
Anomaly Scan vs Routine Pregnancy Ultrasound
Parents sometimes use the terms “ultrasound” and “anomaly scan” interchangeably, but not every pregnancy ultrasound has exactly the same purpose.
A routine ultrasound may be performed for different reasons, such as checking fetal growth, fetal position, amniotic fluid, or other pregnancy-related observations.
The anomaly scan is specifically focused on detailed fetal anatomical assessment during the appropriate stage of pregnancy.
The examination may therefore involve more measurements and specific anatomical views.
Your doctor decides which ultrasound examination is appropriate according to the pregnancy’s needs.
What Happens After the Anomaly Scan?
After completing the anomaly scan, the findings are documented in a report.
Depending on the results, your doctor may:
- Continue routine prenatal care
- Recommend a follow-up ultrasound
- Monitor fetal growth
- Recommend targeted imaging
- Suggest fetal echocardiography
- Refer you for specialist consultation
- Recommend other investigations when clinically appropriate
A normal scan generally means that the structures assessed appeared as expected within the limitations of ultrasound.
It does not mean that every possible condition has been excluded.
For this reason, continuing regular prenatal appointments remains important throughout pregnancy.
Common Misconceptions About Anomaly Scan
“A normal scan guarantees a completely healthy baby.”
Not necessarily. Ultrasound can assess many anatomical features, but it cannot detect every genetic, developmental, or medical condition.
“A repeat scan means something is wrong.”
Not always. A repeat examination may simply be needed because the baby was in an unfavorable position or certain images were not clear enough.
“The scan can predict everything about the baby’s future health.”
No. The anomaly scan primarily evaluates fetal anatomy and development that can be visualized at the time of examination.
“A longer scan means there is a problem.”
Not necessarily. Detailed imaging can take time, particularly when the baby is moving or positioned in a way that makes specific structures difficult to see.
“Parents can interpret the report themselves.”
It is better to discuss the complete report with your obstetrician. Medical terminology can be misleading when individual observations are viewed outside their clinical context.
Frequently Asked Questions
Is the anomaly scan mandatory?
The recommendation depends on the pregnancy and your healthcare provider’s prenatal care plan. Discuss the timing and need for the examination with your obstetrician.
Can I eat before an anomaly scan?
Preparation requirements can vary. Follow the instructions provided by your diagnostic centre or doctor before the appointment.
Can the baby’s gender be seen during the scan?
Ultrasound may sometimes make fetal sex visible, but laws and regulations regarding disclosure vary by location. In India, disclosure of fetal sex is prohibited under the PCPNDT Act.
What should I bring to Iris Diagnostic?
Carry previous ultrasound reports, relevant medical records, referral documents if provided, and any preparation information given by your doctor or the diagnostic centre.
Is a 20-week scan the same as an anomaly scan?
The detailed fetal anatomical examination is commonly performed around 18–22 weeks, so people may informally refer to it as a 20-week scan. The exact timing depends on individual circumstances and medical advice.
What if the anomaly scan detects a possible abnormality?
Your doctor will explain the finding and may recommend additional imaging, specialist consultation, or other testing. A screening finding does not automatically establish a diagnosis.
Does a normal anomaly scan mean I do not need more pregnancy scans?
Not necessarily. Further scans depend on your pregnancy, medical history, fetal growth, and your doctor’s recommendations.
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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