The anomaly (level II) scan: your 18–22 week detailed scan

Medically written by Dr. Sushma Dhakal, MBBS · MD (Obstetrics & Gynaecology) · Fellowship in Fetal Medicine · Updated 30 October 2026 · 3 min read

The anomaly scan, also called the level II scan, TIFFA scan or mid-pregnancy scan, is a detailed ultrasound of your baby from head to toe. It is the main scan for checking that the baby's organs have formed normally, and for most families it is a reassuring, special moment.

When is it done?

The best time is 18 to 22 weeks of pregnancy (usually around 20 weeks). By then the organs are large enough to see clearly, and there is still time for further tests and planning if anything needs attention.

What does the doctor check?

Head and brain: skull shape, brain ventricles, cerebellum and other structures.
Face: lips (to look for cleft lip), eyes and profile.
Spine: the bones and the skin covering them (for spina bifida).
Heart: four chambers, valves and the main blood vessels.
Chest and abdomen: lungs, diaphragm, stomach, abdominal wall, kidneys and bladder.
Limbs: arms, legs, hands and feet.
Placenta, cord and fluid: position of the placenta, the three vessels in the cord, and the amount of amniotic fluid.
Growth: measurements of the head, abdomen and thigh bone to check size for dates.

What can it detect, and what not?

A detailed scan by an experienced specialist detects most major structural problems, such as spina bifida, many heart defects, and problems of the kidneys or abdominal wall. However, no scan can find every condition. Some problems develop later in pregnancy, some are too small to see, and chromosomal or genetic conditions may not show any visible sign. A normal anomaly scan is very reassuring, but it is not a guarantee.

Soft markers

Sometimes the scan shows a "soft marker", a small finding such as a bright spot in the heart or mild kidney dilatation. These are common in healthy babies. On their own they usually mean very little; their meaning depends on your earlier screening results. Your doctor will explain whether any follow-up is needed.

If a problem is found

Hearing that something may be wrong is frightening. You will be given time and clear information about what the finding means, whether further tests (such as a fetal echo, neurosonography, MRI or amniocentesis) would help, and what care your baby may need after birth. Many conditions can be treated well when they are known before delivery.

How to prepare

Allow 30–60 minutes; the baby's position sometimes means walking around and re-scanning.
You do not need a full bladder. Wear comfortable two-piece clothing.
Bring your earlier scan and blood test reports.
Your partner or a family member is welcome to join you.

Have questions about your pregnancy?

Book a consultation with Dr. Sushma Dhakal, Fellowship-trained fetal medicine specialist (FMF UK certified).

Book this scan Request Counselling

Frequently asked questions

When is the anomaly scan done?

Between 18 and 22 weeks of pregnancy, usually around 20 weeks.

Can the anomaly scan detect all problems?

No. It detects most major structural problems, but some conditions cannot be seen or appear later in pregnancy.

What is a soft marker?

A small scan finding that is common in healthy babies. Its importance depends on your other screening results.

How long does the anomaly scan take?

About 30–60 minutes, depending on the baby's position.

This guide is for general information only and is not a substitute for personal medical advice. Every pregnancy is different. Please consult your doctor about your own situation. In an emergency, go to the nearest hospital.