What Is Fetal Echocardiogram And Why Is It Done?

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About one in 100 babies are born with a congenital heart anomaly, one of the common birth defects according to research (1) (2).

To minimize the risks of a heart defects at birth, the health of the fetus should be assessed and any problems should be diagnosed early during pregnancy. Fetal echocardiography is one of the procedures your doctor may consider when he suspects something wrong with the fetal heart.

In this MomJunction article, we tell you about fetal echo testing and how it helps diagnose the abnormalities and the risks associated with them.

What Is Fetal Echocardiography?

Fetal echocardiography or fetal echo is a non-invasive ultrasound imaging test that assesses the heart of the unborn baby. It is usually done in the second trimester, between 18 and 24 weeks of gestation. It can also be done later during your pregnancy if the need arises.

The test uses sound waves to create an echocardiogram or a picture of the fetal heart. It studies the fetal heart issues and abnormalities, heart rhythm disruptions and evaluates the functioning of the heart (3).

Fetal echo is similar to ultrasound except that it allows for a better examination of the structure and function of the fetal heart.

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Why Is Fetal Echocardiography Important?

The fetal echo test is important for the following reasons:

  • A fetal echocardiogram could reveal abnormalities in the functioning of the heart, which can be a serious health concern. Serial readings a period of time may be required to establish a diagnosis in some cases.
  • When you receive the results and know where exactly the problem lies, you will be able to manage your pregnancy better. You can also prepare yourself to care for the baby postpartum.
  • The test could also help your doctor plan the necessary treatment after a correctional surgery.
  • You will also be able to seek counseling and support to make the right decisions after the birth of the baby.

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When Is Fetal Echocardiography Recommended?

Your doctor would recommend this test if any of the previous tests indicate abnormal heartbeat in the fetus. Fetal echo is recommended in the following scenarios (3) (4):

  • If you or your partner have been diagnosed with congenital heart issues.
  • If there is a family history of heart diseases such as hypertension.
  • If the fetus has been diagnosed with heart disease or fetal arrhythmia.
  • If the fetus is diagnosed with a genetic abnormality (such as Down syndrome) or other conditions (such as brain or kidney abnormality).
  • If you consume alcohol or take drugs during pregnancy.
  • If you are on certain acne and seizure medications that can cause congenital heart diseases.
  • If you have medical conditions such as diabetes (gestational or otherwise), rubella, phenylketonuria or lupus.
  • In case of abnormal amniocentesis.
  • If you have conceived through the IVF method or other such reproductive technology that can increase the risks of congenital heart defects (5).
  • In the case of nuchal translucency, when there is fluid accumulation under the skin behind the fetus’ neck (6).
  • If the fetus has the twin-to-twin transfusion syndrome in the case of monochorionic twin pregnancies (7).

An experienced ultrasonographer or ultrasound technician performs this test. Sometimes, the obstetricians may perform it while the pediatric cardiologist interprets the results.

Fetal echo is not necessary for every one, but if the doctor deems it necessary, you’ll have to undergo the procedure. Sometimes, the prenatal ultrasound examinations performed during regular prenatal checkups can also give you information about the fetal heart.

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Do You Need To Prepare For The Fetal Echo Procedure?

No. Unlike other prenatal ultrasounds that need you to have a full bladder, a fetal echocardiogram does not require any preparation from you. The duration of the test will range from 30 minutes to two hours. It is recommended that you take your partner or a family member along with you for the test.

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What Is The Procedure Of Fetal Echocardiography?

A fetal echo is similar to a pregnancy ultrasound and takes about 30 minutes to an hour (8). Fetal echo can be abdominal echocardiography (done through the abdomen) or transvaginal echocardiography (done through the vagina) (9).

Abdominal echocardiography

  • This ultrasound procedure is widely used to assess the heart of the fetus.
  • During the test, you need to lie down on the bed, when a lubricating gel is applied on the belly.
  • A handheld ultrasound transducer is gently moved over the abdomen. The transducer sends high-frequency sound waves that create an echo as they move through the mother’s and the baby’s skin to the fetal heart tissues.
  • The echoes reflect on the computer screen and create images depicting the area, shape, and structure of the heart.
  • After the process, the gel-like substance is cleaned, and you can get back to your day.
  • The entire procedure takes about 30 to 120 minutes, depending on the fetal heart complexity.

There is no pain or discomfort during the procedure.

Transvaginal/ Endovaginal echocardiography

  • It is typically done in the early pregnancy stages particularly the first trimester.
  • For this, you need to undress from the waist down and lie down on the bed.
  • A small probe that is inserted into the vagina uses sound waves to create the pictures of the fetal heart.
  • The endovaginal method provides clearer pictures compared to the abdominal ultrasound.

Sometimes, the following procedures are used to get more detailed pictures and information of fetal heart (10).

  • 2D echocardiography: It is used to assess the actual size, exact movement, and structure of the fetal heart. The echo on the screen appears cone-shaped and lets the doctor see the real-time motion of the fetal heart structures.
  • 4D echocardiography: This procedure uses a special probe that obtains a series of pictures of the fetal heart. You can view the photos at the same time in different planes or reconstruct them for acquiring a realistic image of the heart. This technique helps the specialist to understand and detect the heart condition better.
  • Doppler echocardiography: It is used to measure and assess the flow of blood between the valves and chambers of the heart. It detects if there is an abnormal flow, indicating problems with the valves, chambers or heart walls.
  • Color Doppler: It is an improved form of Doppler echo. Here, different colors help assess the direction of the blood flow which makes the interpretation easier.

Accurate interpretation of the results of the echocardiogram is essential to prescribe the right treatment.

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What Do The Fetal Echocardiogram Results Indicate?

During the follow-up, your health care provider or pediatrician will interpret the results for you (11).

A normal result indicates that there is no cardiac abnormality. But the fetal echo cannot be used to diagnose every possible condition, such as a hole in the heart that cannot be diagnosed initially. So you may have to undergo this test again, as and when your doctor feels it is necessary, to reduce any significant risks.

If the results are abnormal, you may be asked to undergo additional tests such as a fetal MRI or other ultrasounds. Anomalies detected could include a heart defect or rhythm abnormality, among other problems which could put your baby at high risk.

The doctor will then explain the results of the echo test during your follow-up appointments. You can also get answers to any questions you may have at this time and get a reference to a child specialist.

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Are There Any Risks Associated With The Fetal Echo Test?

No, fetal echo is only an ultrasound and poses no risk to the baby. It is a safe, and sometimes necessary, procedure to ensure that you and your baby are healthy. However, the test has its limitations.

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What Are The Limitations Of Fetal Echocardiography?

Fetal echocardiography:

  • Cannot assess every abnormality
  • Cannot detect mild issues within the valves or a hole in the heart
  • May give inconclusive results, and you may be asked to go for a retest or additional tests

Next, we answer a few commonly asked questions about fetal echocardiography during pregnancy.

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Frequently Asked Questions

1. How does it feel during the fetal echo test?

Since it is an ultrasound, you will feel slightly cold and wet because of the conducting gel on the belly. You will not, however, feel any ultrasound waves.

2. What is a 3-vessel view in fetal echocardiography?

One of the standard views in a fetal echo, the three-vessel view gives you an axial view of the heart. It that snips the upper part of arches, and highlights from the right ventricle to the pulmonary trunk. It is an ultrasound image containing:

  • Full-length picture of the pulmonary artery (P) which arises from the right ventricle
  • Cross section of ascending aorta (A)
  • Superior vena cava (V)

This image, labeled as PAV, is checked to see if all of the above vessels fall in one line. Also, the aorta and the pulmonary artery should be perpendicular to each other. If not, there is a chance of a heart defect (transposition of the great vessels) (12).

3. What is a short axis view of a fetal echocardiogram?

The short axis view is an oblique view of the right ventricle and shows all the connections of the right heart. This ultrasound image shows the inlet, trabecular and outlet parts, and can be attained only if the fetus is in the posterior spine (13).

4. Why is harmonic imaging used in fetal echocardiography?

Harmonic imaging is used to improve the spatial resolution of the ultrasound image, enable visualization, and contrast resolution of the image to look at the subtle differences (14).

5. What are the different views for a fetal echocardiogram?

The different, specific views obtained through an optimized visualization of a standard fetal echocardiogram include (15):

  • Basic views: abdominal situs view, four chamber view, five chamber view, three-vessel view (3VV), and three-vessel-trachea view (3VT).
  • Additional views: short axis view, aortic arch view, ductal arch view, Superior and inferior vena cava views (Bicaval views), long axis left ventricle outflow tract view, and right ventricular outflow tract view, and highlighted interventricular septum view.

6. Can fetal echo detect VSD?

Yes. A fetal echo can help detect and evaluate a VSD (ventricular septal defect), which is an opening in the interventricular septum (that is a wall between the two lower heart chambers) (16).

7. Can fetal echo detect TGA?

Yes, fetal echo analyzes the position of the atrial septum to detect transposition of great arteries (TGA), which is a rare fetal cardiac anomaly that causes cyanosis in the newborn.

8. Is fetal echo necessary to diagnose single umbilical artery?

Yes, fetal echo helps diagnose single umbilical artery, which is a rare condition associated with the increased possibility of congenital heart disease (CHD) (17).

9. What is an atrial septal defect (ASD), and how does fetal echo detect it?

ASD causes a hole in the wall separating the two top chambers of the heart and is detected using the four-chamber view of the fetal echo (18).

10. What does the M-mode fetal cardiogram explain?

The M-mode echocardiogram is used to time the diastolic and systolic phases of the fetal heartbeat cycle (19).

11. Does fetal echo detect pulmonary atresia?

Yes, fetal echo detects pulmonary atresia, which is a defect of the pulmonary valve and controls the flow of blood from the right ventricle to the pulmonary artery. The fetal echocardiogram can be highly accurate in diagnosing this (20).

12. Could fetal echocardiography detect pericardial effusion?

Yes, pericardial effusion could be detected by a fetal echo using the real-time M-mode ultrasound. It helps rule out fetal hydrops or structural anomalies caused by excess fluid between the heart and surrounding sacs (21).

13. How important is an EIF in fetal echocardiography?

Echogenic intracardiac focus (EIF), which is a small bright spot inside the fetal heart chambers, can be detected in a fetal echocardiogram for assessing the risk for birth defects (22).

14. What is Tetralogy of Fallot, and how it is detected?

Tetralogy of Fallot (TOF) is a heart abnormality that refers to four, related heart defects occurring together – ventricular septal defect (VSD), pulmonary stenosis, overriding aorta and right ventricular hypertrophy. A three-vessel view of the fetal echo can help detect these four related defects easily (23).

15. Can fetal echo diagnose vascular rings?

Yes, fetal echocardiography can diagnose vascular rings, which are the congenital abnormalities of the aortic arch, and lead to respiratory symptoms (24).

Should there be a need for echocardiography during your pregnancy, talk to your doctor about it in detail. Knowing what happens during a diagnostic procedure helps you better prepare for it and also be ready to deal with the results it gives.

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