What is a blue baby in medical terms?

Answer 1

"Blue baby" is an old-fashioned lay term for newborns with cyanotic heart defects. A cyanotic heart defect is one in which the patient is a bit blue in color (cyanotic) due to inadequate oxygenation of the blood. In cyanotic heart defects, this hypoxemia is due to inappropriate mixing of oxygenated and deoxygenated blood in the heart. One possible cause is the vetricular septal defect (sometimes abbreviated VSD); a lay term for a VSD is a "hole in the heart."

Answer 2

A blue baby is an infant born with a congenital heart defect that causes a bluish coloration of the skin as a result of cyanosis (deoxygenated blood). The color is most noticeable around the lips and at the tips of the fingers and toes. This indicates a severe condition which usually requires surgical repair.

To read more about this condition, see the Related Link.

Answer 3

As the wikipedia page states there are a few different causes of Blue Baby, here is the link and you can check them all out.