While the exact cause of congenital heart defects, such as truncus arteriosus, is unknown, several factors may increase the risk of a baby being born with a heart condition. These include:

  • Viral illness during pregnancy. If a woman contracts rubella (German measles) or another viral illness during early pregnancy, the risk of congenital heart defects in her baby is increased.
  • Poorly controlled diabetes during pregnancy. Diabetes that isn't well-managed can increase the risk of birth defects, including heart defects.
  • Certain medications taken during pregnancy. Many medications aren't recommended for use during pregnancy because of potential risks to the fetus.
  • Certain chromosomal disorders. Children with DiGeorge's syndrome or velocardiofacial syndrome have an increased risk of truncus arteriosus. These conditions are caused by an extra or defective chromosome.
  • Smoking during pregnancy. Continuing to smoke while pregnant increases the risk that the baby will be born with a heart defect.
Oct. 01, 2015