TIFFA Anomaly Scan at 20 Weeks: What Exactly Does Your Doctor Examine?
Written and medically reviewed by Dr. Mathew Thomas, Fetal Medicine Consultant & Radiologist, Kollam — based on 10+ years of clinical fetal imaging practice.
Key Facts at a Glance
- TIFFA (Targeted Imaging for Fetal Anomalies) is the detailed 18–22 week anatomy survey of pregnancy; the ideal window is 19–20 weeks.
- It systematically examines the brain, face, spine, heart, chest, abdomen, kidneys, limbs, placenta and amniotic fluid.
- A complete TIFFA scan takes 30–45 minutes and detects roughly 70–90% of major structural abnormalities.
- It is not a Down syndrome screening test — chromosomal risk is assessed at the 11–14 week NT scan or by NIPT.
- Congenital heart defects affect about 8 in 1,000 babies, which is why the cardiac views are a critical part of the protocol.
From Dr. Mathew's Practice
The question I am asked most often during a TIFFA at our Kollam centre is: is everything normal? What I want every parent to know is that a proper anomaly scan cannot be rushed — I follow the same structured organ-by-organ checklist for every baby, in the same order, every time. When a scan is completed in under 20 minutes, critical views are usually missing. I would rather take 45 unhurried minutes and show you each organ on the screen as I check it.
— Dr. Mathew Thomas, FMF UK Certified Fetal Medicine Specialist, Kollam
At around 18 to 20 weeks of pregnancy, your baby is large enough for a detailed examination of virtually every organ system, yet still small enough to be fully captured in a single ultrasound frame. This is the TIFFA scan — Targeted Imaging for Fetal Anomalies — and it is the most important diagnostic ultrasound of your entire pregnancy.
What is the TIFFA Scan?
TIFFA stands for Targeted Imaging for Fetal Anomalies. It is a systematic, organ-by-organ survey of your baby's anatomy performed by a trained fetal medicine specialist. Unlike a routine obstetric ultrasound that checks basic growth parameters, the TIFFA scan is an extended examination following a strict anatomical protocol.
When is the TIFFA Scan Done?
The TIFFA scan is ideally performed at 19 to 20 weeks. Before 18 weeks, some structures are not fully developed enough for clear visualization. After 22 weeks, the baby begins to become too large and the position makes some views harder to obtain. The optimal window is 18 to 22 weeks.
Complete Checklist: What is Examined During a TIFFA Scan?
A complete TIFFA scan systematically evaluates the following:
Brain and Head
- Head shape and skull integrity
- Lateral ventricles (hydrocephalus screening)
- Cavum septum pellucidum
- Cerebellum shape and size (Dandy-Walker malformation screening)
- Cisterna magna measurement
- Posterior fossa structures
Face
- Upper lip continuity (cleft lip detection)
- Nasal bone presence
- Orbits (eye size and position)
- Profile view (micrognathia screening)
Spine
- Cervical, thoracic, lumbar, and sacral spine
- Spina bifida and neural tube defect screening
- Skin covering over the spine
Heart (Detailed Cardiac Survey)
- Four-chamber view (heart position, size, symmetry)
- Left ventricular outflow tract (LVOT) — aorta
- Right ventricular outflow tract (RVOT) — pulmonary artery
- Three-vessel and tracheal view
- Ductal arch and aortic arch
- Fetal heart rate and rhythm
Congenital heart defects are the most common major structural abnormality, affecting 8 in every 1,000 babies. A detailed cardiac survey is one of the most critical parts of the TIFFA scan.
Chest
- Lung echogenicity and size
- Diaphragm integrity (congenital diaphragmatic hernia screening)
Abdomen
- Stomach bubble (confirming swallowing)
- Kidneys — size, echogenicity, collecting system
- Bladder visibility and size
- Anterior abdominal wall integrity (gastroschisis, omphalocele)
- Umbilical cord insertion at the abdomen
- Bowel
Limbs
- Both humeri and femora (long bone measurement)
- Forearms, lower legs
- Hands — presence and opening
- Feet — position (clubfoot screening)
Placenta and Fluid
- Placental location (placenta previa screening)
- Amniotic fluid index (AFI)
- Cervical length (preterm birth risk)
- Umbilical cord structure (three-vessel cord)
How Long Does the TIFFA Scan Take?
A thorough TIFFA scan takes 30 to 45 minutes. It cannot be rushed — each organ system requires careful evaluation. If your scan was completed in under 20 minutes, it is unlikely to have been a complete targeted anomaly survey.
What Happens if Something is Found?
If a potential abnormality is identified, your doctor will explain the finding clearly and calmly. Most findings require further evaluation — a follow-up scan, a fetal echocardiogram, or an additional specialist opinion. Many apparent concerns on ultrasound turn out to be normal variants. You will never be left without a clear path forward.
References & Further Reading
- [1]ISUOG practice guidelines — routine mid-trimester fetal ultrasound
- [2]NHS (UK) — the 20-week screening scan, patient information
- [3]Fetal Medicine Foundation (FMF), London — anomaly scan certification standards
This article is written for patient education and reflects clinical practice at our centre in Kollam, following FMF and ISUOG protocols. It does not replace a personal consultation with your obstetrician or fetal medicine specialist.
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