The NT (Nuchal Translucency) scan is one of the most important investigations of your first trimester — and timing matters enormously. This guide covers everything expectant mothers in Mumbai need to know about the NT scan.
What is the NT Scan?
The NT scan measures the nuchal translucency — the fluid-filled space at the back of the baby's neck — using high-resolution ultrasound. An increased NT measurement can be associated with chromosomal conditions including:
- Down syndrome (Trisomy 21)
- Edwards syndrome (Trisomy 18)
- Patau syndrome (Trisomy 13)
- Other chromosomal and structural abnormalities
- Some cardiac defects
When Must the NT Scan Be Done?
The NT scan must be performed between 11 weeks 2 days and 13 weeks 6 days of pregnancy. This window is strict — after 14 weeks, the fetus is too large for an accurate NT measurement. We strongly recommend booking your appointment as soon as you know you are pregnant to ensure a slot within this window.
The NT measurement is only meaningful when taken within the correct gestational age window. At AV Scan, we follow the strict FMF (UK) protocol — ensuring your result is as accurate as possible.
What Does the NT Scan Involve?
The NT scan is performed using transabdominal ultrasound — the same type of scan used for routine pregnancy checks. A moderately full bladder may help in early scans. The scan typically takes 20–30 minutes and includes:
- Measurement of nuchal translucency thickness
- Assessment of nasal bone presence (absent nasal bone is associated with Down syndrome)
- Assessment of ductus venosus blood flow
- Measurement of fetal heart rate
- Dating of pregnancy (crown-rump length)
- Detection of major structural abnormalities visible at this gestation
Combined First Trimester Screening
The NT measurement alone gives a risk estimate, but accuracy significantly improves when combined with blood tests (PAPP-A and free beta-hCG) — this is called Combined First Trimester Screening. When combined, the detection rate for Down syndrome exceeds 90%. Ask your obstetrician about arranging the blood tests alongside your NT scan.
What Happens if the NT Measurement is High?
An increased NT does not mean your baby definitely has a chromosomal problem — it indicates an increased risk that warrants further investigation. Your doctor may recommend:
- Non-Invasive Prenatal Testing (NIPT) — a blood test that analyses fetal DNA
- Chorionic Villus Sampling (CVS) — a diagnostic test performed at 11–14 weeks
- Amniocentesis — a diagnostic test performed after 15 weeks
NT Scan at AV Scan Diagnostics, Dadar West
At AV Scan Diagnostics, NT scans are performed on the GE Voluson E10 — the world's most advanced obstetric ultrasound system — by FMF (UK) and ISUOG certified radiologists. We follow strict FMF protocols, ensuring your NT measurement meets international quality standards.
To book your NT scan in Dadar West, Mumbai, call or WhatsApp us at +91 98200 51511.