Congenital heart disease is a disorder that is present at birth, and studies show that the incidence is around eight cases per thousand live births. The heart is formed during the first four - ten weeks of gestation, and alterations to this process can affect normal development, leading to heart defects. There are various types of heart defects: abnormalities that affecta single part of the heart (for example a valve) but also, highly complex abnormalities where there is severe damage to the cardiac architecture. The seriousness of the disease and the effects on child health vary: some forms have no real impact on child health and allow a normal life, while others are incompatible with life.