Pregnancy scans explained
NT scan vs anomaly (TIFFA) scan: what each checks and when
Two different scans at two different stages — the NT scan early for chromosomal-risk screening, the anomaly (TIFFA) scan later for detailed anatomy. They are complementary, not alternatives. Here’s how they differ and why both matter.
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The short answer
The NT (nuchal translucency) scan is done at about 11–14 weeks as part of first-trimester screening — it assesses the risk of chromosomal conditions and checks early development. The anomaly scan (TIFFA — Targeted Imaging For Fetal Anomalies) is done at about 18–22 weeks — a detailed survey of the baby’s anatomy. They answer different questions at different stages, so they are complementary, not either/or.
NT scan vs anomaly (TIFFA) scan at a glance
| Feature | NT scan | Anomaly (TIFFA) scan |
|---|---|---|
| Timing | ~11–14 weeks | ~18–22 weeks |
| Main purpose | Chromosomal-risk screening + early checks | Detailed fetal anatomy survey |
| What it assesses | Nuchal translucency, nasal bone, early structure (often with blood markers) | Brain, heart, spine, face, limbs, organs, fluid, placenta |
| Result | A risk estimate (with combined screening) | A structural assessment |
| Do you need both? | Yes — different stages, different questions | |
What the NT scan checks
At 11–14 weeks, the NT scan measures the fluid at the back of the baby’s neck (nuchal translucency), looks at early structures such as the nasal bone, and — combined with a first-trimester blood test — gives a risk estimate for the common chromosomal conditions. It is a screening assessment, not a diagnosis. For how the blood-test options compare, see NIPT vs the double marker test.
What the anomaly (TIFFA) scan checks
At 18–22 weeks, the anomaly (TIFFA) scan is a careful, structured survey of the baby’s anatomy — brain, heart, spine, face, limbs, abdominal organs, the amniotic fluid and the placenta. It is the detailed “head-to-toe” check of how the baby is formed, and it answers a completely different question from the early NT scan.
How they fit your scan schedule
Both sit within a planned series of pregnancy scans rather than replacing one another: the NT scan early, the anomaly scan in the second trimester, and growth/wellbeing scans later as needed. Our fetal-medicine team coordinates the timing so each scan is done in its correct window and nothing is missed. Where a screening result needs confirmation, the next step is a diagnostic test — explained on our prenatal screening page.
Why expert imaging matters
The value of both scans depends on the quality of the imaging and the experience of the person performing them. We follow the ISUOG imaging protocol, allow enough time to image carefully, and explain findings clearly and calmly — so you understand what each scan can and cannot tell you, without pressure. Care is led by our fetal-medicine team alongside Dr. Priyadatt Patel.
Planning your pregnancy scans?
We’ll make sure each scan is booked in its right window — clear guidance, no pressure.
WhatsApp +91 97234 31544 Contact & directionsFrequently asked questions
Is the NT scan the same as the anomaly scan?
Do I need both scans?
When is the TIFFA scan done?
What does the NT scan detect?
Is the anomaly scan necessary?
Medically reviewed by Dr. Priyadatt Patel — Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead, Advanced Laparoscopic Surgeon & IVF and Endometriosis Programme Lead. Last reviewed June 2026. This page provides general clinical orientation only and is not a substitute for personal medical advice; no outcome is guaranteed.
Dr. Priyadatt Patel
Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead
MS OBGyn · Pregnancy Care · Advanced Gynaecological Ultrasound · Fertility Preservation
ESHRE / ESGE / AAGL / ASRM guideline-aligned practice. 3D Karl Storz precision technique. Fertility-preservation-first philosophy. Evidence-based decisions, honest counselling, long-term outcomes orientation.
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