Fetal echocardiography is a test that uses sound waves (ultrasound) to evaluate the baby’s heart for problems before birth.

Fetal echocardiography is a test that is done while the baby is still in the womb. It is usually done during the second trimester of pregnancy, when the woman is about 18 – 24 weeks pregnant.

The procedure is similar to that of a pregnancy ultrasound. You will lie down for the procedure.

The test can be performed on your belly (abdominal ultrasound) or through your vagina (transvaginal ultrasound).

In an abdominal ultrasound, the person performing the test places a clear, water-based gel on your belly and then moves a hand-held probe over the area. The probe sends out sound waves, which bounce off the baby’s heart and create a picture of the heart on a computer screen.

In a transvaginal ultrasound, a smaller probe is inserted into the vagina. A transvaginal ultrasound can be done earlier in the pregnancy and produces a clearer image than an abdominal ultrasound.

No special preparation is needed for this test.

The conducting gel may feel slightly cold and wet. You will not feel the ultrasound waves.

This test is done to detect a heart problem before the baby is born. It can provide a more detailed image of the baby’s heart than a regular pregnancy ultrasound.

The test can show:

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

The test may be done if:

• A sibling or other family member had a heart defect or heart disease
• A routine pregnancy ultrasound detected an abnormal heart rhythm or heart problem in the unborn baby
• The mother has type 1 diabetes, lupus, or phenylketonuria
• The mother has rubella during pregnancy
• The mother abused drugs or alcohol during pregnancy
• The mother has been exposed to drugs that can damage the baby’s developing heart (such as some epilepsy drugs and prescription acne medications)
• An amniocentesis revealed a chromosome disorder

The echocardiogram finds no problems in the unborn baby’s heart.

Abnormal results may be due to:

• A problem in the structure of the heart (congenital heart disease)
• Disorders of heart function
• Heart rhythm disturbances (arrhythmias)

The test may need to be repeated.

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.

If the health care provider finds a heart problem, a detailed ultrasound may be needed to check the rest of the unborn baby’s body for other abnormalities. Some heart rhythm problems may be treated before the baby is born. Others are treated soon after birth.

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Laboratory Evaluation. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 423.

Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital Heart Disease. In: Libby P, Bonow RO, Mann DL, Zipes DP. Brawnwald’s Heart Disease. 8th ed. Philadelphia, Pa:Saunders Elsevier;2007:chap 61.