A baby who is cyanotic (blue), due frequently to a heart malformation that stops the baby's blood from becoming fully oxygenated. The bluish color reflects the deoxygenated state for the bloodstream. (Oxygenated blood is red.) Often the expression "blue baby" can be applied to a young child who is cyanotic due to failure because of the lung area to oxygenate the blood.
a baby born with a bluish color; generally has actually a defective heart