Anomaly Scan — Detailed Fetal Anatomic Assessment
The anomaly scan (also called the TIFFA scan or 20-week scan) at 18–22 weeks is the most detailed routine fetal anatomic assessment in pregnancy. Performed by Dr. Shreya Iyengar Patel using AI-enhanced 3D/4D sonography under ISUOG standards.
What the Anomaly Scan Covers
A systematic fetal anatomic survey per ISUOG (International Society of Ultrasound in Obstetrics and Gynaecology) guidelines: brain and cranial structures, face and palate, neck, chest and heart, abdominal organs (stomach, kidneys, bladder, abdominal wall integrity), spine and skeletal system, limb completeness, and external genitalia. Approximately 50–70% of major structural anomalies are detected at this scan.
Timing and Technique
Best performed between 18 and 22 weeks. Earlier than 18 weeks: fetal organs may not be fully visualised. Later than 22 weeks: imaging quality reduces, and decision options narrow. Transabdominal scan with patient lying supine. Duration approximately 30–45 minutes for a thorough examination.
Beyond Anatomy — Additional Assessments
Placental position (low-lying or previa identification), cervical length measurement (preterm-birth risk screening), amniotic fluid volume, fetal growth (biometry), Doppler studies of uterine arteries (preeclampsia risk refinement).
When Findings Need Further Evaluation
Most anomaly scans are reassuring. When concerns are raised, options include: detailed targeted re-scan, fetal echocardiography (for cardiac findings), MRI in select cases, genetic counselling, invasive diagnostic procedures (amniocentesis), or specialist referral. Decisions are always yours, with full information and support.
Soft Markers and What They Mean
Soft markers are minor ultrasound findings that on their own usually mean nothing, but in combination may slightly increase risk for chromosomal conditions. Examples: echogenic intracardiac focus, choroid plexus cyst, mild pyelectasis, short femur. We interpret these in clinical context — including first-trimester screen results, NIPT (if done), and maternal age.
Frequently Asked Questions
When should the anomaly scan be performed?
Optimally between 18 and 22 weeks. We typically schedule at 19–21 weeks for the best balance of organ visualisation and timing.
How long does the scan take?
30–45 minutes for a thorough systematic survey. Occasionally repeated visits are needed if the baby is in an unfavourable position.
What if the baby is in a difficult position?
Common. We may ask you to walk around, eat something sweet, or return for a follow-up scan after a few days when the baby has moved.
Can the anomaly scan determine the sex of the baby?
External genitalia are typically visible at 18–22 weeks. In India, sex disclosure during prenatal ultrasound is prohibited by the PCPNDT Act 1994 and is strictly not communicated.
What if something is found on the anomaly scan?
Most findings are minor variants or soft markers requiring no action. Significant findings are discussed thoroughly with you, additional imaging may be arranged, and specialist referral provided. You are never alone in decision-making.
Is the scan safe for my baby?
Yes. Diagnostic obstetric ultrasound has been used for decades with no demonstrated harm. ISUOG-aligned protocols use the minimum necessary exposure (ALARA principle).
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.
Science City Road, Ahmedabad 380060
Mon–Sat 11:00–20:00 · +91 97234 31544
Naranpura, Ahmedabad
Mon–Sat 08:30–10:30 · +91 70460 02566