Fetal echocardiography (also known as fetal echo) is an ultrasound test that focuses on the developing fetus’ heart. Like echocardiography tests in adults, fetal echocardiography checks for possible heart defects and evaluates the function of the heart during pregnancy.
This procedure is usually performed by a pediatric cardiologist, or by a gynecologist that specializes in maternal-fetal medicine (MFM, also known as perinatologist).
How is the test performed?
Fetal echo is a relatively simple procedure, during the scan an ultrasound transducer is placed on the abdomen, like other prenatal ultrasound scans. This test focuses on the fetus’ heart, and also includes a color Doppler ultrasound – a technique that allows identifying flow patterns, such as the speed and direction of blood flow within the chambers and blood vessels.
The scan is considered safe for both the mother and fetus and involves only mild discomfort. It is performed as a screening test, or after test results that may indicate heart problems.
When is the test performed?
The test can be performed during all stages of pregnancy, after test results detect a risk for heart defects, or due to a family history of heart disease. For instance, women with gestational diabetes are at high risk for fetal heart defects and are therefore referred to a fetal echocardiography as part of their screening tests.
In other cases, fetal echo is performed after heart defects are detected during prenatal screening tests. Occasionally, the test is recommended if the fetus’ heart rate is sound to be too slow during previous tests.
The test is recommended to women with the following risk factors: family history of congenital heart defects, genetic disorders found in the fetus that are linked to heart defects (such as DiGeorge syndrome, Noonan syndrome), exposure to teratogenic substances that may affect the fetus (such as Lithium or epilepsy medication), gestational diabetes, maternal lupus, or certain infections (especially rubella).
Some recommend fetal echo in cases of IVF and when the fetus was conceived by assisted reproductive technologies. In addition, the test is recommended after abnormal nuchal translucency results, diagnosed chromosome abnormalities, and in some instances of multiple pregnancy (twins).
The optimal time for performing this procedure is between weeks 18-22 of pregnancy, when the structure of the fetus’ heart can be clearly observed. After heart defects are detected, further testing is required. These tests may include a thorough assessment of maternal and fetal wellbeing, relevant family history, and a karyotype test for detecting chromosomal abnormalities (such as Down syndrome).
Which diseases can the test detect?
The main aim of this procedure is detecting congenital heart defects and assessing them.
The test includes a thorough examination of all parts of the fetal heart including the four chambers, and heart vessels such as the pulmonary artery and the aorta. Occasionally, technical difficulties may arise due to the position of the fetus, maternal weight, or too early stages of pregnancy.
The main fetal heart defects include left-to-right shunt, and right-to-left shunt. These are also known as cyanotic cardiac defects.
Some defects do not have a great affect on the future of the fetus and child (such as a small hole in the heart), while others pose danger to the fetus’ life postnatally (such as a transposition of the great arteries) which requires corrective surgery and supportive treatment.
the decision on continuing the pregnancy after a severe heart defect is detected is up to the parents, their beliefs, and preferences, after a thorough explanation of their healthcare provider.