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Trichy Fetal Medicine and Fertility Centre
Pregnancy scans

What Happens If an Anomaly Is Found During the 20-Week Scan?

The reassuring part is that a concern raised at this scan is the start of a conversation, not the end of one. No, and this surprises many parents.

In this guide
Doctor gently discussing scan findings with a pregnant couple in a clinic

Few appointments are as anticipated as the 20-week scan, which is why an unexpected remark from the sonographer lands so hard. The reassuring part is that a concern raised at this scan is the start of a conversation, not the end of one. What follows is usually a focused scan with a fetal medicine specialist, and that visit often answers the question that brought you there.

Does an abnormal finding always mean something is wrong?

No, and this surprises many parents. Reports sometimes list "soft markers", minor ultrasound features that also appear in healthy babies. One marker alone rarely changes the picture, though it can justify a second look. Occasionally the baby's position simply hid a structure, and a repeat scan settles the matter.

What happens at the specialist scan?

Expect a longer, slower examination than the 20-week scan. The specialist concentrates on the area of concern and tries to settle four things: whether the finding is actually there, whether it stands alone or is part of a pattern, how significant it looks, and whether it could change as the pregnancy progresses.

If the heart or brain is involved, a fetal echocardiogram or fetal neurosonography may be added. Bring your earlier reports, and consider bringing someone with you. Two people hear more than one, particularly on a stressful day.

Which tests might be suggested next?

That depends on the finding. Genetic counselling is often the first step, because it helps you understand what the finding could imply and which tests are worth considering.

If a chromosomal or genetic cause is a real possibility, amniocentesis may be discussed. In this diagnostic test, a small sample of amniotic fluid is taken with a thin needle under ultrasound guidance. It carries a small risk of miscarriage, which your doctor should explain before you decide. Some brain findings may call for a fetal MRI. In other pregnancies, repeating the scan after a few weeks shows whether a finding is stable.

You may also hear about NIPT. It is a screening test that estimates the chance of certain chromosomal conditions, so it cannot explain a structural finding seen on ultrasound.

What can the outcome look like?

Honestly, it varies. Some findings turn out to be harmless. Others are monitored through pregnancy and treated after birth, sometimes with delivery planned at a hospital that has newborn specialists. A small number of conditions can be treated before birth. And some findings are serious, in which case families need time, clear information and support.

Who helps with the decisions?

A good counselling session lays out the options without steering you. The decisions belong to you and your partner. In India, the Medical Termination of Pregnancy (Amendment) Act, 2021 sets gestational limits and provides for Medical Board review where substantial fetal abnormalities are found, so long gaps between scans and consultations are best avoided. Your doctor can explain what applies to your situation.

When should you call your doctor urgently?

Seek medical help promptly for heavy bleeding, leaking fluid, severe abdominal pain or fever.

What matters most

Before you leave any appointment, ask what exactly was seen, how certain the finding is, what the next test will tell you and when the results will be ready. Request copies of your reports too. Parents in Trichy who have been advised further fetal assessment can contact Trichy Fetal Medicine and Fertility Centre through its official website.

You can read about how we run the second opinion scan at our centre, and who performs it, on the team page.

Common questions

Sources

  1. Khalil A, et al. ISUOG Practice Guidelines (updated): performance of the routine mid-trimester fetal ultrasound scan. Ultrasound in Obstetrics & Gynecology, 2022. · isuog.org
  2. NHS. 20-week screening scan. · nhs.uk

This guide is for general information and does not replace a consultation with a fetal medicine specialist.

In line with the PCPNDT Act, we do not perform or support sex determination.

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