Transposition of the great arteries/vessels is a congenital heart defect, in which the two main arteries leaving the heart are reversed (transposed). This creates two parallel circulation systems leaving a shortage of oxygen in the blood flowing from the heart to the rest of the body. In this disease the lungs do not oxygenate the blood and without an adequate supply of oxygen-rich blood the child faces serious complications or death if adequate measures are not taken.

Transposition of the great arteries is usually diagnosed within the first hours to weeks of life primarily by the blue-grey skin color. Corrective surgery soon after birth is the usual treatment. Having a baby with this defect can be alarming, but with proper treatment, the outlook is promising.



Transposition of the great arteries symptoms include:

  • Blue color of the skin (cyanosis)
  • Shortness of breath
  • Lack of appetite
  • Poor weight gain



Transposition of the great arteries occurs during fetal growth when the baby's heart is developing. Why this defect occurs is unknown.

When transposition of the great arteries occurs, the positions of the pulmonary artery and the aorta are switched. Oxygen-poor blood circulates through the right side of the heart and back to the body without passing through the lungs. Oxygen-rich blood circulates through the left side of the heart and right back into the lungs without being circulated to the rest of the body.

Some factors, such as rubella or other viral illnesses during pregnancy, maternal age over 40, or maternal diabetes, may increase the risk of this condition, but in most cases the cause is unknown.


Risk Factors

Several factors may increase the risk of a baby being born with this condition. They are:

  • A family history of transposition of the great arteries or another congenital heart defect
  • A history of rubella or another viral illness in the mother during pregnancy
  • Poor nutrition during pregnancy
  • Drinking alcohol during pregnancy
  • A mother older than age 40
  • A mother whose diabetes is poorly controlled
  • Down syndrome in the baby



Complications of transposition of the great arteries may be lack of oxygen to tissues, heart failure and lung damage.

All babies with this disorder arteries need to have surgery early in life, usually within the first week. Complications of the surgery may occur later in life, including:

  • Heart rhythm abnormalities (arrhythmias)
  • Narrowing of the arteries that supply blood to the heart (coronary arteries)
  • Heart muscle weakness or stiffness leading to heart failure
  • Leaky heart valves



There is no known way to prevent this defect, but some of the problems experienced later in life by babies born with TGA can be prevented or lessened if the defect is detected early.