An NT scan (Nuchal Translucency scan) is a special ultrasound done during early pregnancy to measure the fluid-filled space at the back of a baby’s neck.
- When is it done? Between 11 and 13 weeks + 6 days of pregnancy
- What is measured? The thickness of the nuchal translucency (NT)
- It is part of the first-trimester screening test
Why is the NT Scan Important?
Screens for Chromosomal Conditions
An increased NT measurement may indicate a higher risk of:
- Down syndrome (Trisomy 21)
- Edwards syndrome
- Patau syndrome
Important: The NT scan does not diagnose these conditions. It only estimates risk.
Helps Detect Heart Problems
Babies with increased NT thickness may have a higher chance of:
- Congenital heart defects
Your doctor may recommend a fetal echocardiography later if NT is high.
Assesses Overall Early Development
It also:
- Confirms baby’s growth
- Checks heartbeat
- Confirms due date
What is Considered Normal?
- Usually less than 3 mm is considered normal
- The exact normal range depends on the baby’s size (CRL – crown-rump length)
Your doctor combines:
- NT measurement
- Maternal age
- Blood test results (PAPP-A & free β-hCG)
This combination gives a risk ratio (example: 1 in 1,000).
Is It Safe?
Yes.
It is a non-invasive ultrasound and is safe for both mother and baby.
What Happens If NT Is High?
Do not panic. Your doctor may suggest:
- NIPT (Non-Invasive Prenatal Testing)
- Chorionic villus sampling (CVS)
- Amniocentesis
- Detailed anomaly scan later