Can Fetal Echo Detect Heart Defects in Babies?

A fetal echocardiogram is a specialised ultrasound of the unborn baby's heart. It is the best prenatal test for examining the heart's structure and function. Parents often ask how reliable it is. The answer is that a fetal echo detects most significant heart defects, but some conditions are difficult or impossible to see before birth.

What can a fetal echo detect?

• Underdeveloped heart chambers, such as hypoplastic left heart syndrome
• Large holes between chambers, such as atrioventricular septal defects
• Abnormal connections of the major arteries, such as transposition of the great arteries
• Tetralogy of Fallot and similar complex defects
• Valve problems that significantly affect blood flow
• Narrowing of major vessels in many cases
• Heart rhythm problems, such as heart block or fast rhythms
• Heart muscle problems and fluid around the heart

What may be missed?

Small holes

Small ventricular septal defects may be hard to see and often close on their own after birth.

Atrial septal defects

The foramen ovale is normally open before birth, so atrial septal defects usually cannot be diagnosed prenatally.

Patent ductus arteriosus

The ductus is a normal fetal vessel and is expected to be open before birth.

Coarctation of the aorta

Narrowing of the aorta can be difficult to confirm before birth and may be suspected rather than diagnosed.

Progressive problems

Some valve narrowings or muscle conditions develop or worsen later in pregnancy or after birth.

What affects accuracy?

• Gestational age at the time of scan
• Baby's position
• Maternal body type and abdominal scar tissue
• Amniotic fluid levels
• Quality of the equipment
• Experience of the specialist

Sometimes a repeat scan is needed if views are unclear.

What happens if a defect is found?

The specialist explains the finding, its likely impact and treatment options after birth. Parents may meet a paediatric cardiologist, and genetic testing may be offered. Delivery may be planned at a hospital with neonatal cardiac care.

The part to remember

A fetal echo provides valuable information about the baby's heart and helps families and doctors prepare. Understanding its strengths and limits sets realistic expectations. Dr Malathi G. Prasad offers fetal echocardiography in Trichy.

When you are ready, the fetal echo service page covers timings and preparation; questions about your own situation are best put to our specialists.

Related guides

• What Happens If a Fetal Echo Shows a Heart Problem?
• Fetal Echo vs Anomaly Scan: What's the Difference?
• Anomaly Scan in Pregnancy: Complete Guide to the 20-Week / TIFFA Scan