“Pink baby” congenital defects are heart abnormalities in which systemic oxygenation is usually maintained, so the child does not show obvious central cyanosis.
The problem is often not a lack of oxygen, but abnormal blood flow. This may be caused by a left-to-right shunt, sending oxygenated blood back towards the lungs, or by an obstruction to normal systemic blood flow.
Examples include ASD, VSD, PDA and Coarctation of the Aorta.
The term is useful as a simple physiological description, but it is not absolute: some lesions can become cyanotic if the circulation changes significantly over time.
