Congenital heart disease

The mammalian heart is essential for pumping blood around the body, but its complexity poses a huge challenge during development. This How science works explains how the heart is formed, what can go wrong and how understanding the intricacies of its formation could help us in treating defects

Figure 1 (a) An adult human heart, showing the direction of blood flow through the heart (b) The human circulatory system. The pulmonary circulatory system takes deoxygenated blood from the heart to the lungs, where it becomes oxygenated and is returned back to the heart. The systemic circulatory system takes oxygenated blood from the heart around the body and returns it to the heart

It is estimated that between 1% and 5% of the human population are born with structural or functional problems with their hearts — known as congenital heart disease. These problems result from errors that happen when the baby’s heart is forming in the womb. They are the most common birth defect, and are the most common non-infectious cause of child death.

The impact of congenital heart disease varies — some defects can be corrected with surgery but some defects are so severe that newborn babies die. However, many defects go unnoticed, or if they are found they may not require any treatment. Therefore, it is possible that the prevalence of congenital heart disease in the population may be even higher than estimates suggest.