Imaging
Anomaly Scan
The anomaly scan is a detailed ultrasound around 20 weeks of pregnancy that checks the baby’s physical development.
Quick answer
Anomaly Scan: what it is and what the results mean
The anomaly (20-week) scan is a detailed ultrasound examination of the baby’s body, carried out around 18 to 21 weeks. It systematically checks the baby’s organs, limbs, spine, heart and growth.
- Why it is done: It is done to look for physical conditions that may affect the baby, check that the organs are developing normally, assess the position of the placenta, and confirm growth and the number of babies.
- Understanding results: Most scans show the baby developing as expected.
What it is
The anomaly (20-week) scan is a detailed ultrasound examination of the baby’s body, carried out around 18 to 21 weeks. It systematically checks the baby’s organs, limbs, spine, heart and growth.
Why it is done
It is done to look for physical conditions that may affect the baby, check that the organs are developing normally, assess the position of the placenta, and confirm growth and the number of babies.
What to expect
Gel is applied to your tummy and a probe is moved over it while the sonographer examines the baby carefully. It usually takes about 30–45 minutes, and you can sometimes find out the baby’s sex if you wish and the service offers it.
Understanding the results
Most scans show the baby developing as expected. If something needs a closer look, further scans, specialist referral or additional tests may be arranged and discussed with you.
Good to know
Risks and limitations
Ultrasound is considered safe. However, the scan cannot detect every condition, and some problems are not visible or develop later, so a reassuring scan does not guarantee everything.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Anomaly Scan: frequently asked questions
Can the anomaly scan find every problem?
No. It detects many physical conditions but cannot find them all — some are not visible on ultrasound or develop later — so a normal scan is reassuring but not an absolute guarantee.
Can I find out the baby’s sex at this scan?
Often yes, if you wish and your local service offers it, though it depends on the baby’s position and cannot always be seen clearly. Some services do not routinely tell you.
Related tests
Other imaging investigations
Sources
Where this is drawn from
- NHS — Screening and pregnancy
- NICE — antenatal and screening guidance
- UK National Screening Committee
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