Fetal echocardiography refers to a detailed ultrasound examination of the fetal heart, over and above the careful screening of the heart we perform during every ultrasound scan.
Congenital heart defects are the leading cause of infant mortality due to birth defects. The prevalence of fetal heart defects is estimated to about 14.6 per 1000 fetuses and can often be missed on routine sonography. About 25% have critical defects that require surgery or intervention shortly after birth and therefore prenatal diagnosis is essential for optimal management and outcome. At San Diego Perinatal Center, we have state of the art imaging equipment so that patients get the most comprehensive screening evaluation of the fetal heart available.
A complete fetal echocardiogram excludes 80 to 90 percent of major cardiac defects. The most common abnormalities that could be missed ae small atrial and ventricular septal defects.
The following table from the Journal of the American Heart Association summarizes the current recommendations for referral for fetal echocardiogram. Fetal echocardiography is ideally performed at 22-24 weeks. For select high risk patients, we can perform early fetal echocardiography at 13-14 weeks gestation. It is important to notify your provider if you have any of these risk factors.
Fetal Echocardiogram Indications
|Table 3. Common Indications for Referral for Fetal Echocardiogram
|Indications with higher risk profile (estimated >2% absolute risk)
Maternal pregestational diabetes mellitus
Diabetes mellitus diagnosed in the first trimester
Maternal phenylketonuria (uncontrolled)
Maternal auto-antibodies (SSA/SSB+)
– ACE inhibitors
– Retinoic acid
– NSAIDs in third trimester
Maternal first trimester rubella infection
Maternal infection with suspicion of fetal myocarditis
Assisted reproduction technology
CHD in first degree relative of fetus (maternal, paternal or sibling with CHD)
First or second degree relative with disorder with Mendelian inheritance with CHD association
Fetal cardiac abnormality suspected on obstetrical ultrasound
Fetal extracardiac abnormality suspected on obstetrical ultrasound
Fetal karyotype abnormality
Fetal tachycardia or bradycardia, or frequent or persistent irregular heart rhythm
Fetal increased NT >95% (≥3 mm) Monochorionic twinning
Fetal hydrops or effusions
|Indications with lower risk profile (estimated >1% but <2% absolute risk)
– Anticonvulsants Lithium
– Vitamin A
– SSRIs (only paroxetine)
– NSAIDs in first/second trimester
CHD in second degree relative of fetus
Fetal abnormality of the umbilical cord or placenta
Fetal intra-abdominal venous anomaly
|Not indicated (≤1% risk)
Maternal gestational diabetes mellitus with HbA1c <6%
– SSRIs (other than paroxetine)
– Vitamin K agonists (Coumadin), although fetal survey is recommended
Maternal infection other than rubella with seroconversion only
Isolated CHD in a relative other than first or second degree
|ACE indicates angiotensin-converting enzyme; CHD, congenital heart disease; HbA , hemoglobin A ; NSAID, nonsteroidal anti-inflammatory drug; NT, nuchal translucency; and SSRI, selective serotonin reuptake inhibitor
|Source: Donofrio et al, “Diagnosis and Treatment of Fetal Cardiac Disease” AHAjournals.org
What if a Cardiac Abnormality is Found?
First, we will perform a comprehensive evaluation of the baby, to assess for any other abnormalities. Because most cardiac defects carry a markedly increased risk that the baby has a chromosomal problem, we will arrange genetic counseling and offer genetic amniocentesis testing. Presuming that the baby has no other abnormalities and normal chromosomes, we will then recommend and arrange a fetal echocardiogram with the pediatric heart specialists at Rady Children’s Hospital-San Diego, who can provide you with greater detail about the nature of the abnormality, and develop a treatment plan for the pregnancy.
If you have specific concerns about your baby having a congenital cardiac defect, either based upon a prior pregnancy affected by congenital heart disease, others in the family, such as yourself or your husband, who have had surgery for a heart defect, or drug or medication exposures, then please contact our office early in the pregnancy for genetic counseling, and to decide whether a detailed fetal heart ultrasound will be recommended.