A fetal echo or fetal echocardiography is an ultrasound test performed to evaluate the heart of the fetus during pregnancy and is often done as early as 20-24 weeks but can be done later in pregnancy too.

Echocardiography or Echo assesses the heart's structures and function. A small probe called a transducer (similar to a microphone) is placed on the mother's abdomen above the uterus and sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed in certain locations and at certain angles, the ultrasonic sound waves move through the mother's and baby's skin and other body tissues to the baby's heart tissues, where the waves bounce (or "echo") off of the heart structures. The transducer picks up the reflected waves and sends them to a computer. The computer interprets the echoes into an image of the heart walls and valves.

Fetal echocardiography can help detect fetal heart abnormalities before birth, allowing for faster medical or surgical intervention once the baby is born. This improves the chance of survival after delivery for babies with serious heart defects.

When is a fetal echocardiogram necessary?

fetal echocardiography is not done routinely in all pregnancies and is only done in certain indications such as when the regular ultrasound finds an anomaly or if there is a history requiring the echo.

Regular anatomic ultrasound tests that are done usually around 20 weeks provide general information on different parts of the fetus including the head, chest, abdomen, and extremities.  The regular ultrasound checks the fetus' heart to make sure it has all four chambers. 

The following are indications to perform a fetal echocardiogram :

• A routine prenatal ultrasound has discovered possible heart abnormalities. 
• A routine prenatal ultrasound has identified other congenital (present at birth) anomalies such as kidney, brain or bone abnormalities.
• A family history of congenital heart disease (such as parents, aunts or uncles, or grandparents) or if a sibling was born with a congenital (present at birth) heart defect
• A chromosomal or genetic abnormality discovered in the fetus
• If a mother has taken certain medications that may cause congenital heart defects, such as anti-seizure medications or prescription acne medications
• If the mother has abused alcohol or drugs during pregnancy
• If a mother has diabetes, phenylketonuria, or a connective tissue disease such as lupus
• If the mother has had rubella during pregnancy

How is a fetal echocardiogram performed?

A fetal echocardiogram is performed by a specialist who is specially trained to perform the echocardiogram. The test is typically performed by placing a probe over the mother's abdomen to visualize the fetal heart.

During the test the transducer probe will be moved around to obtain images of different locations and structures of the fetal heart. Techniques sometimes used to obtain detailed information about the fetal heart include the following:

• 2-D (2-dimensional) echocardiography
  This technique is used to "see" the actual structures and motion of the heart structures. A 2-D echo view appears cone-shaped on the monitor, and the real-time motion of the heart's structures can be observed. This enables the physician to see the various heart structures at work and evaluate them.
• Doppler echocardiography
  This Doppler technique is used to measure and assess the flow of blood through the heart's chambers and valves. The amount of blood pumped out with each beat is an indication of the heart's functioning. Also, Doppler can detect abnormal blood flow within the heart, which can indicate such problems as an opening between chambers of the heart, a problem with one or more of the heart's four valves, or a problem with the heart's walls.
• Color Doppler
  Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow. This simplifies the interpretation of the Doppler images.

Fetal echocardiography can help detect fetal heart abnormalities before birth, allowing for faster medical or surgical intervention once the baby is born. fetal echocardiography does not detect all anomalies. Detecting an anomaly often improves the chance of survival after delivery for babies with serious heart defect.

Other tests or procedures that may be needed include the following:

• additional ultrasounds or echocardiography (to confirm the diagnosis, follow fetal growth, and monitor fetal well-being)
• amniocentesis - a test performed to determine chromosomal and genetic disorders and certain birth defects. The test involves inserting a needle through the abdominal and uterine wall into the amniotic sac to retrieve a sample of amniotic fluid.
• genetic counseling - providing an assessment of heritable risk factors and information to patients and their relatives concerning the consequences of a disorder, the probability of developing or transmitting it, and ways in which it can be prevented, treated, and managed.