A fetal echocardiogram is a specialized, non-invasive ultrasound that creates detailed images of an unborn baby’s heart. It uses sound waves to examine the heart’s structure, function, and rhythm before birth. This examination provides a far more in-depth assessment than the limited view of the heart seen during a routine obstetrical ultrasound. It assesses the heart chambers, valves, and blood flow patterns, helping physicians diagnose potential cardiac conditions in the fetal stage.
Why a Fetal Echocardiogram is Necessary
The fetal echocardiogram is necessary when a pregnancy has a higher risk for congenital heart defects (CHDs). CHDs are among the most common types of birth defects. While most pregnant individuals do not require this specialized scan, certain maternal, fetal, or familial factors prompt a referral. Identifying these conditions prenatally allows for better management planning and improved outcomes after delivery.
Maternal Indications
Maternal health conditions are one set of indications for the test. Pre-existing conditions such as insulin-dependent diabetes mellitus or connective tissue diseases like lupus increase the risk of having a baby with a CHD. Exposure to certain medications during early pregnancy, including some anti-epileptic drugs, also warrants evaluation. A history of maternal infection with rubella can also be a reason for the specialized scan.
Fetal Indications
Fetal risk factors often become apparent during routine prenatal screening. If a standard obstetric ultrasound suggests a possible structural heart abnormality or an issue with the baby’s heart rhythm, a fetal echo is recommended for a definitive diagnosis. Other suspicious findings include an increased nuchal translucency during first-trimester screening or the detection of abnormalities in other major organ systems.
Known genetic or chromosomal conditions in the fetus are strong indications, as they are often associated with a high incidence of CHDs. If the baby is diagnosed with an abnormal heart rate or rhythm, a fetal echo assesses the underlying electrical and structural cause. The presence of issues like twin-to-twin transfusion syndrome also necessitates this detailed cardiac evaluation.
Familial Indications
The final category involves a family history of congenital heart disease. If the mother, the baby’s father, or another child has a CHD, the risk for the current pregnancy increases, prompting a referral. The risk level is often highest when the mother has a history of CHD. This familial consideration ensures appropriate monitoring during the pregnancy.
The Standard Timing for the Examination
The timing of the fetal echocardiogram is chosen to maximize image clarity and diagnostic accuracy. The standard window for performing a transabdominal fetal echo is during the second trimester, typically between 18 and 24 weeks of gestation. This period aligns with the routine anatomy scan, allowing for a comprehensive assessment once the cardiac structures are fully formed.
Imaging before 18 weeks is challenging because the small size of the heart structures makes obtaining detailed measurements difficult. Although the heart is formed early, the improved image quality and larger structures at 18 to 24 weeks provide the best window for a definitive diagnosis. Scans performed earlier often require a repeat examination later in the second trimester for confirmation.
In high-risk pregnancies, a physician may suggest an earlier scan, sometimes performed as early as 14 to 16 weeks. This is generally done using a transvaginal ultrasound probe for clearer images when the fetus is deep within the pelvis. Even with an earlier scan, a follow-up examination in the standard 18-to-24-week window is often scheduled to ensure all structures are evaluated at an optimal size.
Scans may also be performed later in pregnancy for monitoring purposes or if an issue is identified that could develop or worsen. For certain abnormalities, serial fetal echocardiograms may be necessary up until 34 to 36 weeks gestation to track the condition’s progression. If an issue is found, the timing ensures there is time for parental counseling and preparation for specialized care at birth.
What to Expect During the Procedure
The fetal echocardiogram is performed similarly to a standard prenatal ultrasound; it is non-invasive and painless. No special preparation, such as fasting or a full bladder, is typically required. The test is conducted as an abdominal ultrasound: a clear gel is applied to the abdomen, and a hand-held transducer probe is moved across the skin.
The procedure is usually performed by a specially trained sonographer, and the images are interpreted by a pediatric cardiologist specializing in fetal congenital heart disease. The examination often takes longer than a routine ultrasound, ranging from 30 minutes to two hours. The duration depends on the baby’s position and the complexity of the heart being evaluated, as multiple heart views and blood flow patterns require detailed assessment.
During the scan, the patient lies down comfortably. The technician may ask them to change position periodically to obtain the clearest pictures of the baby’s heart. The goal is to capture images that evaluate the heart’s position, size, structure, function, and rhythm.
In most cases, the pediatric cardiologist reviews the images and discusses the preliminary results with the family on the same day. If the examination is normal, the pregnancy continues with routine care. If a heart problem is detected, the care team will discuss the specific diagnosis, potential treatment options, and a plan for specialized care immediately following birth.