What does the anomaly scan check for, condition by condition?
In short
- The anomaly scan checks for a named list of conditions. In the NHS schedule, that's 11 of them.
- They cover the brain, spine, face, chest, tummy wall, heart, kidneys, bones and two rare conditions.
- Most babies show no signs of any of them at this scan.
- If something is found, your sonographer and doctor will explain it, and what happens next.
What happens
- The sonographer checks each part of your baby's body against the list of conditions in turn.
- Measurements and images are recorded for your notes.
- You're told at the time if everything looks as expected; anything unclear is explained and a follow-up plan is discussed.
Baby's sex is never revealed
It is illegal in India for anyone -- including your sonographer -- to reveal, or help you find out, the sex of your baby before birth. This is the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994.
Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994. Read the Act (India Code).
The details: numbers and where they differ
The 11 conditions on the NHS list
Anencephaly (the brain and skull not developing fully); open spina bifida (a gap in the spine); cleft lip and palate; diaphragmatic hernia (an opening in the muscle between the chest and tummy); gastroschisis and exomphalos (the tummy wall not closing fully around the bowel); serious heart abnormalities; bilateral renal agenesis (both kidneys missing); severe skeletal dysplasia (a serious bone-growth condition); and two chromosome conditions, Edwards' syndrome (trisomy 18) and Patau's syndrome (trisomy 13).
In the source's own words
During the 20-week scan your baby will be checked for signs of: anencephaly, open spina bifida, cleft lip and palate, diaphragmatic hernia, gastroschisis, exomphalos, serious cardiac abnormalities, bilateral renal agenesis, severe skeletal dysplasia, Edwards' syndrome (trisomy 18), Patau's syndrome (trisomy 13).
NHS (UK), 20-week scan. Quoted verbatim.
The 20-week screening scan, also called the anomaly scan, is an ultrasound scan to look for 11 different conditions in your baby. It also checks your baby's growth. It's usually done when you're between 18 and 21 weeks pregnant.
NHS (UK), 20-week scan. Quoted verbatim.
The numbers
| Measure | Value | Source |
|---|---|---|
| Anomaly scan window (pregnant women (NHS, UK)) | 18–21 weeks gestation | NHS (UK) |
When to call your doctor
- If your sonographer or doctor flags any of these conditions or an unclear finding — ask them to explain exactly what was seen and what the next step is.
- If you don't understand a term used during or after your scan.
Discuss your results with your doctor: this page reports what these sources say, not advice for your situation.
Sources
- NHS (UK), 20-week scan. Quoted verbatim. OGL-style NHS content, free reuse with attribution.
- NHS (UK), 20-week scan. Quoted verbatim. OGL-style NHS content, free reuse with attribution.
Sources checked 2026-09-26. How we source and check every page.
Educational summary of named sources, not medical advice.