Call for all babies to have heart defect test

5th August 2011 - Around six in every 1,000 babies are born with congenital heart defects in England, and now a new study has found a quick, non-invasive test can help identify problems accurately and save lives.

A UK study, published online first in The Lancet  says pulse oximetry is a safe and reasonably accurate test that is more sensitive for spotting heart problems than antenatal screening and clinical examinations. Pulse oximetry works by shining a light source through the skin. The degree of absorbtion of the light indicates how much oxygen the haemoglobin in the blood is carrying. A reduced level of oxygen suggests the heart may not be working properly.

The authors say this test, using a sensor placed on a baby's hand or foot, should be given to all newborns before they leave hospital.

Congenital heart defects

Congenital heart disease is an abnormality of the heart that is present at birth. In some cases it may be diagnosed when the baby is still developing in the womb, but often is not discovered until after the baby is born. It is one of the most common birth defects.

In most cases there is no obvious cause of congenital heart disease, including anything mothers were exposed to during pregnancy.

However, some factors are known to increase heart defect risks:

• Down’s syndrome
• Infections, such as rubella, in the mother during pregnancy
• Poorly controlled diabetes in the mother during pregnancy

If the condition is detected, heart surgery may be performed. 85% of children with congenital heart disease now survive into adulthood.

Heart screening trial

Currently, heart defect screening involves an ultrasound scan during pregnancy and a routine physical examination of the baby shortly after birth.

This is not the first study of pulse oximetry screening for congenital heart defects in newborn babies, but it is the largest so far.

20,055 apparently healthy newborn babies were screened between February 2008 and January 2009 in six maternity units across the UK. They were checked before they left hospital and were followed up after they left until they were 12 months old.

Pulse oximetry detected 75% of critical cases and 49% of all major congenital heart defects.

When 35 babies already suspected of having heart problems after antenatal ultrasound were excluded, the oxygen test's detection rate was 58% for critical cases and 28% for all major cases.

Pulse oximetry combined with routine ultrasound and physical examination at birth detected 92% of critical congenital heart defects, and no baby died with unidentified congenital heart defects.

The test did wrongly identity congenital heart defects in 169 babies - known as 'false positives'. However, the study authors say six of these babies still had significant heart defects, and another 40 babies had other problems requiring treatment, including respiratory disorders and infections which may otherwise have gone undetected at that stage.

Reaction

Reacting to the study results in an emailed statement, Amy Thompson, senior cardiac nurse at the British Heart Foundation, says: "Although great progress has been made in the treatment and care of congenital heart disease, early and rapid detection is key for greater survival.

"Not all babies who are born with a heart defect will show any signs or symptoms, so problems can go unnoticed. This is a promising piece of research which shows how a quick and simple test could help to detect more heart defects and make a real difference."