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Fetal Echocardiography

What does this test do?

A fetal echocardiography uses sound waves to evaluate the baby's heart for problems before birth. The test takes place while the baby is still in the womb, most often during the second trimester when a mother is about 18 to 24 weeks along.

The procedure is similar to a pregnancy ultrasound, and mothers will lie down during the procedure.

A technician will place a clear, water-based gel on the mother’s belly and will move a hand-held probe over the area.

The probe sends out sound waves, which bounce off the baby's heart and create a picture on a computer screen. The test lasts about one to two hours depending on the position of the fetus.

Neither you nor the baby will feel the ultrasound waves, although the conducting gel may feel cold and wet on your skin.

The test can show:

  • Blood flow through the heart
  • Heart rhythm
  • Structures of the baby's heart

The test may be done if:

  • A parent, sibling, or other close family member had a heart defect or heart disease.
  • A routine pregnancy ultrasound detected an abnormal heart rhythm or possible heart problem in the unborn baby.
  • The mother has diabetes (before pregnancy), lupus, or phenylketonuria.
  • The mother has rubella during the first trimester of pregnancy.
  • The mother has used medicines that can damage the baby's developing heart (such as some epilepsy drugs and prescription acne medicines).
  • An amniocentesis revealed a chromosome disorder.
  • There is some other reason to suspect that the baby has a higher risk for heart problems.

What abnormal results mean

Abnormal results may be because of:

  • A problem in the way the baby's heart has formed (congenital heart disease)
  • A problem with the way the baby's heart works
  • Heart rhythm disturbances (arrhythmia)


There are no known risks to the mother or unborn baby.


Some heart defects cannot be seen before birth, even with fetal echocardiography. These include small holes in the heart or mild valve problems.

And sometimes tests cannot see every part of the blood vessels leading out of the baby’s heart. Problems in this area may go undetected.

If the health care provider finds a problem in the structure of the heart, he or she may order a detailed ultrasound to look for other problems with the developing baby.