The 20-week anomaly scan is the most detailed check of your baby's body during pregnancy. It is not a photo session. It examines your baby from head to toe: brain, spine, face, heart, stomach, kidneys, limbs, along with the placenta, amniotic fluid, and growth. Many major problems in how the organs are formed can be seen at this stage. That is why it is done around 20 weeks.
What's actually examined
This one scan checks more parts of the body than any other routine pregnancy scan:
- Brain and spine — checked for structural development and closure
- Face and heart — structural formation, and for the heart, chamber development
- Stomach, kidneys, and limbs — organ position, formation, and proportional growth
- Placenta — position, and whether it's safely clear of the cervix
- Amniotic fluid — volume, which reflects both baby's wellbeing and kidney function
- Growth parameters — whether baby's size matches the weeks of pregnancy
The 4 questions worth asking before you leave
Rather than just hearing "everything looks fine," these four questions get you the specifics that matter:
- Is my baby's growth right for the weeks of pregnancy? This tells you whether baby is getting enough nutrition and blood supply.
- Are the heart, brain, and spine developing normally? These are among the most critical structures evaluated at this stage.
- Is the placenta in a safe position, and is the amniotic fluid normal? Both matter for a healthy pregnancy and for how delivery gets planned later.
- Are there any soft markers or findings that need follow-up? Some findings are not worrying on their own but need a repeat scan, a fetal echo (a detailed scan of baby's heart), or genetic counselling. It is better to know now than be surprised later.
A normal anomaly scan is reassuring, but it doesn't replace the pregnancy check-ups that continue through the rest of your pregnancy.
What a normal result means — and what it doesn't
A normal anomaly scan is reassuring. It means no major problems were seen in the organs checked that day. It does not rule out every possible condition for the rest of pregnancy. That is why your regular pregnancy check-ups continue, whatever this scan shows.
Frequently asked
When is the anomaly scan usually done?
Around the 18–22 week window, commonly referred to as the 20-week scan — early enough to act on findings, late enough for organs to be clearly visible.
Is the anomaly scan the same as a growth scan?
No. This scan focuses on structural development — organs, spine, heart, face, limbs — alongside a growth check. Later growth scans in the third trimester focus mainly on baby's size and wellbeing, not structural detail.
What happens if something unusual is found?
Your doctor will typically recommend follow-up — a repeat scan, a fetal echocardiogram, or genetic counselling, depending on the finding. Many soft markers turn out to be non-significant on follow-up, but they're worth tracking rather than ignoring.
Do I need to prepare for this scan?
No fasting is needed. You also don't need a very full bladder. An empty or comfortably filled bladder is usually fine, because the uterus is now large enough to be seen clearly. Eat your normal meals. If baby is in an awkward position or not moving much, the sonographer may ask you to walk around, change position, or have a snack or drink. Wear comfortable clothes. Expect the appointment to take 30–45 minutes or more, since every part is examined in detail.
Will the 20-week scan tell me my baby's sex?
No. Even though the scan can often show physical features clearly enough to determine sex, revealing or recording it is illegal in India under the PCPNDT Act (Pre-Conception and Pre-Natal Diagnostic Techniques Act), which exists to prevent sex-selective practices. Your sonographer and doctor will not state the baby's sex, and the scan report will not mention it. The scan's purpose stays entirely about checking your baby's structural health.