Heart defects in the developing fetus

Staff members in the divisions of Cardiology and Cardiovascular-Thoracic Surgery treat children with a wide range of cardiovascular disorders. The types of congenital heart disease that can be diagnosed prenatally are expanding as technology constantly improves.

Evaluation of the four chambers of the heart is part of the routine ultrasound examination done by many obstetricians as part of their routine prenatal care around the 20th week of pregnancy. If an obstetrician sees an abnormality in any of the chambers, the valves, or the aortic arch, he usually refers the patient to a pediatric cardiologist.

The cardiologists at Children's Memorial perform a fetal echocardiogram, which is a specialized, focused ultrasound (sonogram) study of the baby's heart while he is still inside the mother's womb. This test produces detailed pictures of the heart's structures and may include a Doppler study, which identifies and measures details of blood flow. The direction, speed, and volume of blood within the heart and blood vessels can be calculated to better identify problems in this area.

Pregnant mothers may also be referred for a fetal echocardiogram if some aspect of the pregnancy suggests an increased risk of delivering a baby with a heart problem. Among the many reasons possible for increased risk are a positive family history (a blood relative with a heart problem), an abnormal genetic screening result (abnormal nuchal translucency, serum screening, or chromosome number), a maternal health condition such as diabetes or rubella (German measles), or other known birth defect in the baby such as diaphragmatic hernia. The following is a list of some of the defects that can be diagnosed prenatally:

  • Holes between the right or left side of the heart (i.e., atrial septal defect, ventricular septal defect)
  • Valve abnormalities including stenosis (narrowing), insufficiency (leaking), or atresia (underdevelopment)
  • Misalignment of the great vessels (aorta and vena cava) and/or their origins and destinations
  • Major heart chamber malformation or chamber absence
  • Abnormal heartbeat rhythms (arrhythmias) due to abnormal electrical pathways or abnormal structure of the heart
  • Abnormal position of the heart (malposition)
  • Abnormal narrowing of the great vessels (coarctation)
  • Heart failure, water around the heart (pericardial effusion), ballooning of a vessel (aneurism), over-thickening of the heart muscle (hypertrophy) and sick heart muscle (myocarditis)

If a baby is diagnosed with a structural heart defect, patients are referred to the cardiovascular surgical team, who provide parents with valuable information to help prepare them for their baby's arrival. Parents receive detailed counseling on the condition suspected and discussion of all aspects of possible treatment plans and options for care after birth.

Read more about the heart defects that the cardiovascular surgical team treats.