CHD: Study could help detect heart defects before birth

Published: 28 September 2025

A New Zealand study led by Dr Teena Gamage may revolutionise early detection of congenital heart disease in unborn babies, a condition that impacts around 1 in 100 births.

Imagine being pregnant, only to discover your baby has a serious heart defect that could have been detected months earlier. 

For hundreds of New Zealand families, that is the devastating reality of congenital heart disease (CHD), which impacts around one in 100 births. 

Now, a new study could revolutionise how CHD is detected in unborn babies, potentially saving lives and improving long-term health outcomes. 

CHD affects around 570 babies annually in New Zealand and is the most common birth defect globally, yet less than half of these cases are picked up during pregnancy ultrasounds. 

CHD is also responsible for nearly a third of stillbirths and can lead to heart failure, life-long neurological deficits and other complications if left undiagnosed. 

A pioneering study led by Dr Teena Gamage from the University of Auckland will investigate whether a simple blood test could change that. 

The research, funded by the Heart Foundation, will explore whether extracellular vesicles (EVs), tiny particles released by the placenta into the mother’s bloodstream, could hold the key to early and accurate detection of CHD.

These vesicles carry fetal DNA, protected within a lipid shell, making them potentially more stable than other forms of cell-free DNA currently used in prenatal testing.  

Teena explains, “EVs carry genetic information that reflects how the baby is developing. If we can decode that information, we may be able to detect heart defects much earlier and more reliably than current methods allow.” 

The study will examine whether DNA carried in EVs can distinguish between healthy and abnormal fetal hearts, which forms the basis of the blood test.

What it could mean for children with CHD

Teena will investigate how CHD affects brain development in utero and into adulthood, helping to explain why some children with heart defects may face developmental delays and cognitive challenges. 

Teena says the research could dramatically improve the quality of life and reduce long-term impact on families and the healthcare system. 

“Early detection in the womb could help develop treatments or early interventions to minimise the impacts of congenital heart disease on brain formation and function. This could help children live longer and healthier lives, and in some cases prevent long-term damage. 

“Early detection could also allow us to move pregnant people who are at risk into specialist care units at hospitals where they and their babies can be monitored.”

Heart Foundation Medical Director Dr Gerry Devlin says Teena’s research has great global potential. 

“This is an exciting study that could one day change the way CHD is detected. The study has potential to not only improve lives but reduce complications for some at birth.”