How is CHD diagnosed in a child? 

Congenital heart disease (CHD) is typically diagnosed through a combination of prenatal screening, newborn physical examinations, and diagnostic imaging tests such as echocardiograms. While many defects are identified during the 20-week anomaly scan or shortly after birth via pulse oximetry, some milder conditions are only discovered later in childhood if a doctor detects a heart murmur or if the child develops symptoms like unusual fatigue or breathlessness. 

What We will cover in this Article 

• Methods used to detect heart defects during pregnancy 

• The role of the newborn physical examination (NIPE) 

• How pulse oximetry identifies low oxygen levels in infants 

• Diagnostic imaging tools including echocardiograms and chest X rays 

• The significance of heart murmurs in childhood diagnosis 

• Identifying CHD in older children and adolescents 

The Pathway to Diagnosis 

In the UK, the diagnostic journey for congenital heart disease often begins before a child is even born. The NHS has a structured screening program designed to catch major heart defects as early as possible. However, the process of diagnosis can occur at various stages of a child’s development depending on the severity of the structural issue. 

Clinicians follow a step-by-step approach, starting with non-invasive bedside tests and moving toward detailed cardiac imaging if an abnormality is suspected. 

Prenatal Diagnosis (Before Birth) 

Most significant heart defects are now found during pregnancy. The mid pregnancy ultrasound, or anomaly scan, is performed between 18 and 21 weeks. Sonographers look at the four chambers of the heart and the major blood vessels to ensure they are formed correctly. If a problem is suspected, a foetal echocardiogram is performed by a specialist to provide a detailed view of the baby’s heart. 

Newborn Screening 

After birth, all babies in the UK receive a physical examination within 72 hours. Doctors or midwives listen to the heart for murmurs and feel for pulses in the baby’s groin. 

Many hospitals now also use pulse oximetry screening. This involves placing a small sensor on the baby’s hand and foot to measure how much oxygen is in their blood. A low oxygen reading can be an early warning sign of a heart defect that hasn’t yet caused obvious symptoms. 

Common Diagnostic Tests 

If a heart condition is suspected, several specialized tests are used to confirm the diagnosis and determine the severity of the defect. 

The Echocardiogram 

This is the most important tool for diagnosing CHD. It is an ultrasound of the heart that allows cardiologists to see the heart’s structure and how blood is flowing through the chambers and valves. It is painless, does not use radiation, and can be performed on babies, children, and even foetuses. 

Electrocardiogram (ECG) 

An ECG records the electrical activity of the heart. Small stickers are placed on the child’s chest to check the heart rate and rhythm. It helps doctors see if a structural defect is putting strain on the heart or causing an irregular heartbeat. 

Chest X ray 

An X ray can show the size and shape of the heart and whether there is extra fluid in the lungs, which can be a sign of certain heart defects. 

Test Type	What it Measures	Why it is Used
Pulse Oximetry	Blood oxygen levels	To catch ‘silent’ defects at birth
Echocardiogram	Heart structure and blood flow	To confirm a specific diagnosis
ECG	Electrical heart rhythm	To check for strain or arrhythmias
Chest X ray	Heart size and lung fluid	To assess the impact on the lungs
Cardiac MRI	Detailed 3D heart images	For complex cases or older children

Diagnosing CHD in Older Children 

Some children are born with mild defects that do not cause symptoms in infancy. These are often found later during routine check ups or when the child starts school and becomes more active. 

The Significance of Heart Murmurs 

A heart murmur is simply an extra sound heard between heartbeats. Many children have ‘innocent’ murmurs that are not caused by a defect. However, if a doctor hears a murmur that sounds unusual, they will refer the child for an echocardiogram to ensure the heart’s structure is normal. 

Symptoms in Older Children 

In some cases, a diagnosis is triggered when a child experiences: 

• Getting tired or breathless more easily than their peers 

• Fainting during exercise or excitement 

• Chest pain during physical activity 

• A blue or grey tinge to the skin or lips when active 

To Summarise 

CHD is diagnosed through a combination of clinical observation and advanced technology. While prenatal scans and newborn checks catch the majority of cases, doctors remain vigilant throughout childhood for signs like heart murmurs or reduced exercise tolerance. Early and accurate diagnosis is the most important step in ensuring children with heart defects receive the specialized care they need to lead healthy lives. 

If you experience severe, sudden, or worsening symptoms such as your child fainting or having a blue tinge to their lips, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK trained physician with experience in general medicine and emergency care. Dr. Petrov’s clinical background includes performing diagnostic procedures and managing cardiac presentations in hospital settings. This content is based on the latest 2026 NHS and NICE diagnostic frameworks to provide parents with accurate and trustworthy medical information.