The detailed anomaly scan: looking at your baby's organs one by one

Seeing your baby on screen as a baby for the first time is an unforgettable moment for many people. The detailed ultrasound is also the most thorough structural check of the pregnancy, so it is natural for it to bring both excitement and a little worry.

When is it done?

The detailed ultrasound (anomaly scan) is usually planned for weeks 18–22, and in practice it may be done up to around week 23. In the Turkish Ministry of Health guideline the second visit falls between weeks 18 and 24, when a basic ultrasound and any needed tests are planned. A basic ultrasound and a detailed ultrasound are not the same thing; the detailed one looks at your baby's structures one by one.

What is looked at?

• Brain and spine: brain structures and the integrity of the spine
• Face: the appearance of the lips and palate
• Heart: the four-chamber view and the large vessels
• Chest and abdomen: lungs, stomach, bowel, liver
• Kidneys and bladder
• Arms, legs, hands and feet
• Umbilical cord: the number of vessels and its attachment
• Placenta: where it lies and how far it is from the cervix
• Amniotic fluid: the amount
• Baby's measurements: growth

If your doctor wishes, cervical length can also be measured; this is not routine for everyone. Whether the sex can be seen depends on your baby's position and on the clinic's practice.

What might it miss?

The detailed scan is a very valuable tool, but it cannot catch every structural difference. Your baby's position, body tissue, the amount of fluid and the position of the placenta all affect image quality. Some problems only become clear after birth or in later weeks. That is not a failing of the equipment or the doctor; it is the nature of ultrasound.

What if some structures cannot be seen?

Sometimes the baby turns away, or areas such as the hands and face are not clear. You may be asked to walk around, have something to drink and be scanned again, or come back after a few weeks. This is very common and not a sign of a problem.

If something is found

In most scans everything looks as expected. If a difference is noticed, your doctor will share it with you calmly and, if needed, suggest extra measurements, referral to a specialist centre or other tests. Some findings are minor and settle on their own. At this stage it is best to go step by step and ask your questions.

What you can do

• Ask how long the appointment is expected to take; it can be long in some clinics.
• Wear comfortable clothes; your tummy will be uncovered.
• Your partner or someone you trust can come with you.
• If you do not follow what is said, ask again without hesitation.
• Wait for your doctor's explanation rather than trying to interpret every image.
• Treat yourself to a small celebration afterwards; for many people this is also when baby movements start to be felt.

When to contact your doctor

• Vaginal bleeding or leaking fluid
• Severe or regular abdominal pain, frequent tightenings
• A clear drop in your baby's movements (once they have started)
• Fever, foul-smelling discharge, severe headache or blurred vision

In a sudden and serious situation, call 112. This article is for information only; for your personal situation, your doctor's advice comes first.