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  • What is transposition of the great arteries?
    • Transposition of the great arteries (TGA) is a heart condition that is present at birth, and often is called a congenital heart defect. TGA might also be referred to as transposition of the great vessels (TGV), but TGA is the more common term.TGA occurs when the two main arteries going out of the heart-the pulmonary artery and the aorta-are switched in position, or "transposed".

      Normally, blood returning to the heart from the body is pumped from the right side of the heart through the pulmonary artery to the lungs. There, it receives oxygen and returns to the left side of the heart. Then, the oxygen-rich blood is pumped from the left side of the heart through the aorta to the body. In TGA, blood returning from the body bypasses the lungs and is pumped back out to the body. This occurs because the main connections are reversed. The pulmonary artery, which normally carries oxygen-poor blood from the right side of the heart to the lungs, now arises from the left side and carries oxygen-rich blood returning from the lungs back to the lungs. The aorta, which normally carries blood from the left side of the heart to the body, now arises from the right side and carries oxygen-poor blood back out to the body. The result of transposition of these two vessels is that too little oxygen is in the blood that is pumped from the heart to the rest of the body.

      CDC estimates that each year about 1,901 babies in the United States are born with TGA. In other words, about 5 out of every 10,000 babies born in the United States each year is born with TGA.

  • What are the symptoms of transposition of the great arteries?
    • Because the main arteries are switched, there are two separate blood circulations instead of a single connected one. Thus, blood with oxygen from the lungs does not get to the rest of the body. This means that TGA is a cyanotic (lacking oxygen) heart defect that leads to a bluish-purple coloring of the skin and shortness of breath.

      Symptoms appear at birth or very soon afterwards. How bad the symptoms are depends on whether there is a way for the two separate blood circuits to mix, allowing some oxygen-rich blood to get out to the body. This mixing can occur through other defects, such as a hole between the bottom chambers of the heart (a ventricular septal defect), or through a shunt that normally is present at birth. Symptoms also can depend on whether other defects are present as well. Common symptoms of TGA include:

      * Blueness of the skin
      * Shortness of breath
      * Poor feeding

  • How do you treat transposition of the great arteries?
    • Surgery might be needed shortly after birth. In most hospitals, a type of surgery called an arterial switch procedure can be used to permanently correct the problem within the first week of life.

      * Without corrective surgery, severe cases of TGA can be fatal during the first 6 months of life. Babies who have surgery to correct TGA sometimes have the following associated conditions later in life:
      * Leaky heart valves
      * Problems with the arteries that supply the heart muscle with blood (coronary arteries)
      * Abnormal heart rhythm (arrhythmias)
      * A decline in function of the heart muscle or heart valves
      * Heart failure
      * Damage to the lungs and difficulty breathing

      Babies with TGA will require lifelong follow-up with a cardiologist. Even so, with proper treatment, most babies with TGA grow up to lead healthy, productive lives.

  • What causes transposition of the great arteries?
    • The cause of TGA is unknown at this time. Scientific researchers have found that some diseases and behaviors might be associated with a higher risk for TGA. These include:

      * The mother having a viral illness during pregnancy
      * The mother having poor nutrition during pregnancy
      * The mother using an excessive amount of alcohol during pregnancy
      * The mother being older than 40 years of age
      * The mother having diabetes during pregnancy
      * The baby having Down syndrome

      CDC works with many researchers to study risk factors that can increase the chance of having a baby with TGA, as well as outcomes of babies with the defect. Following are examples of relevant research findings:
      * TGA seems to occur more often among White babies than non-White babies, although more research is needed.
      * No strong link exists between caffeine use by a mother during pregnancy and the risk for TGA.
      * There are signs that the rate of TGA is decreasing over time.

  • Can transposition of the great arteries be prevented?
    • 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 found early.

      Even so, mothers can take steps before and during pregnancy to have a healthy pregnancy. Steps include taking a daily multivitamin with folic acid (400 micrograms), not smoking, and not drinking alcohol during pregnancy.

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Last Revised: January 28, 2014


Data Query

Transposition of the Great Arteries Data Query
Access the transposition of the great arteries data in the WI EPHT online database. Review the Data Details below to learn about interpreting the data.

The WI EPHT online data has data about other birth defects:
Cleft Lip with or without Cleft Palate
Cleft Palate without Cleft Lip
Down Syndrome (Trisomy 21)
Hypoplastic Left Heart Syndrome
Spina Bifida
Tetralogy of Fallot
Lower Limb Deficiencies
Upper Limb Deficiencies

Data Details

What is the data source?

The website provides data from the Wisconsin Birth Defects Registry, which is maintained by the Birth Defect Prevention and Surveillance program, Wisconsin Department of Health Services.

How does WI EPHT measure birth defects?

The WI EPHT website includes the following measures:

  • Prevalence rate of live births by geography
  • Number of birth defects by geography

What are some considerations for interpreting the data?

While significant effort is made to ensure the accuracy and completeness of the data, there are limitations that are listed below:

  • The Wisconsin Birth Defects Registry does not currently receive reports from all providers in the state. Thus, the numbers presented here represent only a subset of the actual cases.
  • Reporters have up to two years to provide data to the registry, so some cases from the most recent years may not yet be included in the registry.

There are many factors that can contribute to a disease and should be considered when interpreting the data. Some of these include:

  • Demographics, e.g., race, gender, age
  • Socioeconomic Status, e.g., income level, education
  • Geographic, e.g., urban vs. rural
  • Changes in the medical field, e.g., diagnosis patterns, reporting requirements