Frequently Asked Questions About Fetal Echocardiography
What is a fetal echocardiogram?
Echocardiography assesses the heart’s structures and function. A small probe called a transducer (similar to a microphone) is placed on the mother’s abdomen 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, 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.
The fetal cardiology experts at the CHOC Children’s Heart Institute use fetal echocardiography to help detect heart abnormalities before birth, which allows for faster medical or surgical intervention. This early intervention improves the chance of survival after delivery for babies with severe heart defects.
When is a fetal echocardiogram necessary?
It is not necessary for all pregnancies to receive an echocardiogram. The prenatal ultrasound tests that are done prior to birth can give information about whether the fetal heart has developed all four chambers. Most unborn babies do not require any further testing.
Situations in which a fetal echocardiogram may be necessary include, but are not limited to, the following:
- If a sibling was born with a congenital (present at birth) heart defect
- A family history of congenital heart disease
- A chromosomal or genetic abnormality discovered in the fetus
- If a mother has taken certain medications that may cause congenital heart defects, such as antiseizure medications or prescription acne medications
- If the mother has abused alcohol or drugs during pregnancy
- If a mother has diabetes, lupus or phenylketonuria
- If the mother has had rubella during pregnancy
- A routine prenatal ultrasound has discovered possible heart abnormalities
- A routine prenatal ultrasound has identified other congenital anomalies, such as kidney, brain or bone abnormalities.
Fetal echocardiograms are usually performed in the second trimester of pregnancy, at about 18 to 24 weeks. When indicated, earlier screening can often be successfully performed starting at 13 to 14 weeks gestation.
How is a fetal echocardiogram performed?
At CHOC, fetal echocardiograms are performed by one of our pediatric cardiologists who is specially trained to diagnose heart abnormalities. The test is 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 (two-dimensional) echocardiography. This technique is used to “see” the actual structures and motion of the heart structures. A 2-D ultrasound view appears cone-shaped on the monitor, and the real-time motion of the heart’s structures can be observed. This enables the doctor 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, valves and major vessels. 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. This improves the chance of survival after delivery for babies with serious heart defects. Other tests or procedures that may be needed include the following:
- Additional ultrasounds or echocardiograms. Tests done to confirm the diagnosis, follow fetal growth, and monitor fetal well-being.
- Amniocentesis. A test performed to identify the presence of 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.