Pregnancy is a time of excitement, planning, and many questions. Along with routine check-ups, doctors recommend certain ultrasound scans to check how the baby is growing and developing. One of the most important of these is the fetal anomaly scan, also called the anomaly scan, mid-pregnancy scan, or 18–22 week pregnancy ultrasound.
This scan is not just a routine ultrasound. It is a detailed examination of the baby’s organs, body structure, growth, placenta, and amniotic fluid. Its main purpose is to check whether the baby is developing normally and to identify certain structural problems early, while there is still time for counselling, planning, and appropriate follow-up.
Many parents feel anxious before this scan because they worry about what it might find. It is important to know that most scans show normal development. Even when a concern is seen, it does not always mean a serious problem. Sometimes the baby’s position, image quality, or a minor variation can require another scan or further testing. The anomaly scan is a screening test, not a final diagnosis.
What is a Fetal Anomaly Scan?
A fetal anomaly scan is a detailed ultrasound examination performed during the second trimester of pregnancy. It uses sound waves to create images of the baby inside the uterus. Unlike a basic ultrasound that mainly confirms pregnancy or checks the heartbeat, this scan looks closely at the baby’s anatomy and development.
The scan is usually performed by a trained obstetrician, radiologist, or fetal medicine specialist. It evaluates the baby’s brain, face, spine, heart, lungs, stomach, kidneys, bladder, limbs, and other structures. It also checks the placenta, amniotic fluid, umbilical cord, and sometimes blood flow through key vessels.
The anomaly scan is a screening test. This means it helps identify babies who may have a higher chance of having a structural problem. If something unusual is seen, further tests such as a repeat ultrasound, fetal echocardiography, genetic testing, or specialist consultation may be advised.
Why is the Fetal Anomaly Scan Done?
The main purpose of the anomaly scan is to assess the baby’s development and detect certain structural conditions early.
Main reasons for the scan
- To check that the baby’s organs are forming normally.
- To assess growth based on measurements of the head, abdomen, and limbs.
- To examine the brain, spine, face, heart, kidneys, and limbs.
- To check the position and health of the placenta.
- To measure amniotic fluid around the baby.
- To check the umbilical cord and blood flow.
- To look for twins or confirm the number of babies.
- To identify conditions that may need monitoring or treatment after birth.
- To help plan delivery care if a concern is detected.
Why early detection matters
- Some conditions can be monitored during pregnancy.
- Some problems may require delivery at a centre with specialist newborn care.
- Some heart or surgical conditions may need planning before birth.
- Some findings may require further testing to confirm or rule out a problem.
- Parents get time to understand the situation and make informed decisions.
The scan does not detect every possible condition. Some problems may be too small, too subtle, or may develop later in pregnancy. However, it remains one of the most useful tests for checking fetal development.
Ideal Timing for the Scan
The fetal anomaly scan is usually done between 18 and 22 weeks of pregnancy. Many centres prefer around 18 to 20 weeks, because the baby is large enough for detailed organ assessment but still has enough space to move and allow good imaging.
Why this timing is ideal
- The baby’s organs are well formed by this stage.
- The baby is large enough to see important structures clearly.
- There is usually enough amniotic fluid for good ultrasound images.
- The baby still has room to move, which helps view different angles.
- If a concern is found, there is still time for follow-up and planning.
What happens if the scan is done too early
- Some organs may not be clearly visible.
- Certain measurements may not be reliable.
- The baby may be too small for detailed assessment.
- A repeat scan may be needed later.
What happens if the scan is done later
- The baby may be in a difficult position.
- There may be less space around the baby.
- Some views may be harder to obtain.
- Follow-up time may be shorter if a concern is found.
Preparation for the Scan
The fetal anomaly scan usually does not require much preparation. However, a few simple steps can make the appointment smoother.
Before the scan
- Carry your previous ultrasound reports and antenatal records.
- Bring any blood tests or screening reports if advised.
- Wear comfortable, two-piece clothing so the abdomen is easy to access.
- Drink water normally unless your doctor gives specific instructions.
- Do not empty your bladder immediately before the scan unless asked to.
- Reach a few minutes early to complete registration.
- Ask a family member or partner to accompany you if you wish.
During the scan
- You will lie on an examination couch.
- A gel will be applied to your abdomen.
- A small ultrasound probe will be moved over the abdomen.
- The sonographer will take images and measurements.
- You may be asked to change position or hold your breath briefly.
- The baby’s movement and position may affect how long the scan takes.
Is the scan painful?
No, the scan is painless. It uses sound waves, not radiation. You may feel mild pressure from the probe or mild discomfort if the bladder is full, but there is no known harm to the mother or baby from a standard ultrasound scan.
What Does the Fetal Anomaly Scan Check?
The scan checks many parts of the baby and pregnancy. The exact protocol may vary slightly between centres, but the main areas are similar.
Baby’s head and brain
- Head size and shape.
- Brain structures and fluid spaces.
- Face profile and facial bones.
- Eyes and orbits.
- Lips and palate area.
- Skull and skull bones.
Baby’s spine and bones
- Spine alignment and covering.
- Vertebrae and spinal cord area.
- Arms, hands, legs, and feet.
- Long bones and bone growth.
- Movement of limbs.
Baby’s chest and heart
- Heart position and size.
- Four chambers of the heart.
- Major blood vessels.
- Heart rhythm and general cardiac activity.
- Lungs and chest structures.
Baby’s abdomen and organs
- Stomach and bowel.
- Liver and abdominal wall.
- Kidneys and bladder.
- Umbilical cord insertion.
- Abdominal circumference and growth.
Pregnancy-related checks
- Placenta position and appearance.
- Amniotic fluid level.
- Umbilical cord vessels and blood flow.
- Baby’s position.
- Estimated fetal weight in some cases.
- Cervix length if clinically indicated.
What Conditions Can the Scan Detect?
The anomaly scan can detect many structural conditions, but it cannot detect every possible problem. Some conditions are clearly visible, while others may need further testing or may only become apparent later.
Conditions that may be detected
- Brain or skull abnormalities.
- Spine problems such as open spina bifida.
- Facial conditions such as cleft lip or palate.
- Heart defects or abnormal heart structure.
- Kidney or urinary tract problems.
- Abdominal wall defects.
- Limb abnormalities.
- Fluid collections or cysts in some areas.
- Growth concerns.
- Placenta previa or low-lying placenta.
- Abnormal amniotic fluid levels.
Important point about screening
A normal anomaly scan is reassuring, but it does not guarantee that every condition is absent. Some genetic, chromosomal, or developmental conditions may not be visible on ultrasound. This is why doctors may recommend additional screening or diagnostic tests based on family history, blood tests, or other findings.
How Long Does the Scan Take?
The fetal anomaly scan usually takes around 20 to 40 minutes. In some cases, it may take longer.
Reasons the scan may take longer
- The baby is sleeping or in a difficult position.
- The baby is moving too much.
- The mother’s bladder is too full or too empty.
- There is less amniotic fluid than expected.
- The baby’s position makes certain views difficult.
- The sonographer needs to repeat measurements.
- A concern needs closer evaluation.
If some views cannot be obtained, the sonographer may ask you to walk around, change position, or return for a short repeat scan after some time. This is common and does not necessarily mean something is wrong.
Understanding the Results
After the scan, the sonographer or doctor will explain the findings. In many cases, the report is available the same day.
Possible results
- Normal scan, where the baby’s structures and growth appear appropriate.
- Normal scan with a minor variation, which may need routine follow-up only.
- Incomplete scan, where some views could not be seen and a repeat scan is advised.
- Suspicious finding, where further evaluation is needed.
- Confirmed anomaly, where a specific condition is identified and specialist counselling is advised.
What a normal result means
- The baby’s organs appear to be developing normally.
- Growth measurements are within the expected range.
- Placenta and fluid levels appear appropriate.
- No major structural concern was seen during the scan.
What an abnormal or unclear result means
- It does not always mean the baby has a serious condition.
- Some findings are minor variations that resolve on their own.
- Some findings need only repeat imaging.
- Some findings need specialist fetal medicine review.
- Some findings may require genetic counselling or further testing.
What Happens if a Concern is Found?
If the scan shows a possible concern, the doctor will explain the finding clearly and discuss the next steps. It is important not to panic, because many findings need confirmation before any conclusion can be made.
Possible next steps
- Repeat ultrasound after a short interval.
- Detailed fetal echocardiography if the heart needs closer assessment.
- Genetic counselling if a structural issue is seen.
- Diagnostic tests such as amniocentesis in selected cases.
- MRI of the fetus in selected complex cases.
- Referral to a fetal medicine specialist.
- Planning for delivery at a hospital with appropriate newborn support.
- Follow-up scans to monitor growth and fluid levels.
Why follow-up is important
Some conditions change over time. A repeat scan may show that a finding has resolved, remained stable, or progressed. Follow-up helps doctors give more accurate information and plan the safest care for mother and baby.
Is the Fetal Anomaly Scan Safe?
Yes, ultrasound is considered safe when performed by trained professionals for medical reasons.
Safety points
- Ultrasound uses sound waves, not radiation.
- It has no known harmful effects on the mother or baby when used appropriately.
- The scan is non-invasive and painless.
- It is a standard part of antenatal care in many countries.
- The benefits of detecting important conditions outweigh the minimal risks of the test.
What to avoid
- Unnecessary repeated scans without medical advice.
- Commercial scans done only for entertainment without clinical purpose.
- Excessive use of Doppler without indication.
- Relying on ultrasound alone for sex determination where it is legally restricted.
Emotional Support During the Scan
Many parents feel nervous before the anomaly scan. It is normal to worry about the baby’s health and the results.
Helpful ways to manage anxiety
- Remember that most scans show normal development.
- Ask the sonographer or doctor to explain what they are checking.
- Bring a partner or family member for support.
- Write down questions before the appointment.
- Do not search random online images or stories before the scan.
- Wait for the full report and doctor’s explanation before drawing conclusions.
If a concern is found
- Ask for a clear explanation in simple language.
- Ask whether the finding is confirmed or needs further testing.
- Ask what the next step will be.
- Ask whether the condition can be monitored or treated.
- Seek counselling from a fetal medicine specialist if advised.
Follow-Up After the Scan
Follow-up depends on the scan findings and the mother’s overall pregnancy risk.
Routine follow-up
- Continue regular antenatal check-ups.
- Follow the doctor’s advice on diet, rest, and supplements.
- Attend future growth scans if recommended.
- Monitor fetal movements as advised in later pregnancy.
Follow-up if a concern is found
- Attend the repeat scan or specialist appointment as advised.
- Complete any additional tests recommended.
- Keep all reports and images for review.
- Discuss delivery planning if specialist care may be needed.
- Maintain regular communication with the obstetric team.
When to Contact the Hospital
Contact the hospital or doctor promptly if you notice any warning signs during pregnancy.
Warning signs to report
- Vaginal bleeding.
- Severe abdominal pain.
- Reduced fetal movement after 28 weeks.
- Fluid leakage from the vagina.
- Severe headache or visual changes.
- Persistent vomiting.
- Fever with abdominal pain.
- Sudden swelling of face or hands.
Emergency signs
- Heavy bleeding.
- Severe pain.
- Fainting.
- No fetal movement in later pregnancy.
- Severe breathlessness.
- Signs of preterm labour.
Why Choose Rama Hospital for Fetal Anomaly Scan?
A fetal anomaly scan requires careful technique, good imaging equipment, and experienced interpretation. The goal is not only to take images but also to give parents clear, accurate, and supportive information.
- Detailed ultrasound examination by trained specialists.
- Modern imaging equipment for clear fetal views.
- Proper assessment of baby, placenta, fluid, and growth.
- Clear explanation of findings and next steps.
- Access to obstetrics, fetal medicine, and neonatal support if needed.
- Follow-up planning for high-risk or complicated pregnancies.
Frequently Asked Questions (FAQs)
When is the best time to do the anomaly scan?
The ideal time is usually between 18 and 22 weeks of pregnancy. At this stage, the baby’s organs are developed enough to assess clearly, and there is usually enough space and fluid for good images.
Is the fetal anomaly scan painful?
No, the scan is painless and non-invasive. It uses sound waves, not radiation. You may feel mild pressure from the ultrasound probe, but there is no known harm to the mother or baby.
Do I need a full bladder for the scan?
Not always. Some centres prefer a mildly full bladder for better images, while others do not require it. Follow the specific instructions given by your hospital or doctor before the appointment.
How long does the anomaly scan take?
It usually takes 20 to 40 minutes. It may take longer if the baby is in a difficult position, moving a lot, or if some views need to be repeated for a complete assessment.
Can the scan detect all birth defects?
No, the anomaly scan is a screening test and cannot detect every condition. It can identify many structural problems, but some genetic or subtle conditions may need additional tests or may only become apparent later.
What happens if the scan shows a concern?
The doctor will explain the finding and may advise a repeat scan, fetal echocardiography, genetic counselling, or other tests. A concern on scan does not always mean a serious problem and often needs confirmation.
Can the anomaly scan tell the baby’s sex?
The scan may show fetal anatomy, but sex disclosure depends on hospital policy and local legal rules. In India, sex determination and disclosure are legally prohibited, and the focus remains on medical assessment and fetal well-being.
Conclusion
The fetal anomaly scan is one of the most important ultrasound tests during pregnancy. It gives a detailed view of the baby’s development, checks important organs, assesses growth, and evaluates the placenta and amniotic fluid. For most parents, the scan is reassuring and confirms normal development. For some, it helps identify a concern early so that appropriate follow-up and planning can be done.
It is important to remember that this scan is a screening test, not a final diagnosis. A normal result is reassuring, while an unclear or abnormal finding does not automatically mean something is seriously wrong. The right approach is to follow the doctor’s advice, complete any recommended follow-up, and seek clear counselling when needed.
Rama Hospital provides detailed fetal anomaly scanning with a focus on accurate assessment, clear communication, and supportive care for expectant parents. With timely scanning and proper follow-up, families can make informed decisions and feel more confident throughout their pregnancy journey.
