Foetal Echocardiography: Purpose, Procedure, and Risks

Dec 29 , 2023 | 2 min read

Examination of the foetal heart and cardiovascular system by ultrasound (foetal echocardiography) has evolved considerably over the past 3 decades because of advances in imaging technology. In the past, the role of the paediatric cardiologist was to provide a basic, often limited, anatomic cardiac diagnosis with the primary goal of counselling families on what to expect after delivery. Counselling was based on the premise that nothing could be done in utero. With technological advances and increasing experience and interest in foetal medicine, the multidisciplinary speciality of foetal cardiology has emerged. Now, the goal has become to understand the foetus as a patient, knowing that the foetal circulation is different from the postnatal circulation, that structural disease may progress in utero, and that cardiac function and stability of the cardiovascular system play an important role in foetal wellness.

Why is there a need for foetal echocardiography?

Congenital heart defects (CHDs) are the most common congenital anomalies affecting 8 of 1000 live births and are major causes of morbidity and mortality.

CHDs are 6.5 times more common than chromosomal abnormalities
CHDs are four times more common than neural tube defects
CHDs, if not treated /corrected on time, contribute to 20% of neonatal deaths
It is important to have a foetal cardiac evaluation in detail to know the prognosis of heart defect if diagnosed on time by foetal echocardiography.

Who can do foetal echocardiography?

Foetal echocardiography can be performed by a paediatric cardiologist/radiologist/foetal medicine specialist. But the personnel performing foetal echocardiography should be well versed with

Cardiac development & abnormalities
Cardiac anatomy in all projections
Foetal Physiology
Alterations in foetal physiology with CHD
Natural history of the lesion in foetal life & later
Outcome when intervened on time

Indications of foetal echocardiography:

Level II foetal anomaly scan is used to evaluate foetal organs, including foetal heart. Foetal echocardiography is used to define the heart in detail and has defined maternal and foetal indications:

I. Foetal factor:

Suspected structural cardiac abnormality on ultrasound scan
Suspected abnormality in cardiac function on ultrasound scan
Hydrops foetal
Persistent foetal tachycardia (>180)
Persistent foetal bradycardia (<120)or CHB
Frequent episodes of irregular rhythm on routine scanning
Foetal extracardiac anomaly
Nuchal translucency of >3.5
Chromosomal abnormality
Monochorionic twining

Systemic venous anomaly
- Persistent right umbilical vein
- Left Superior vena cava
- Absent ductus venosus

Greater than normal nuchal translucency (3-3.4mm)

II. Maternal factors:

Indicated

Pre-gestational Diabetes Mellitus regardless of HbA1C level
Gestational Diabetes Mellitus is diagnosed in 1st or early 2nd trimester.
In Vitro Fertilization pregnancy
Phenylketonuria
Autoimmune ds with SSA with a prior affected foetus
1st degree relative of foetus with CHD
1st or 2nd degree relative with ds of Mendelian inheritance & a history of childhood cardiac manifestations
Retinoid exposure
1st-trimester Rubella infection

May be indicated

Selected teratogen exposure
ACE inhibitors
Autoimmune ds with SSA without a prior affected foetus
2nd degree relative to the foetus with CHD

Conclusion

Foetal cardiac evaluation should be an integral part of all antenatal scanning.
There are specific indications for referral for foetal echocardiography.
The ideal time for foetal echocardiography is 18-22 weeks of gestation. In selected cases, a follow-up scan is indicated.
A doctor who is well versed in foetal cardiac anatomy and physiology prognosis of heart defect should perform the scan if diagnosed on foetal echo. As an institute policy, paediatric cardiologists should be involved in counselling parents with a foetal diagnosis of CHD.

If a foetus is diagnosed with CHD,
- It is important to inform the treating obstetrician about the cardiac issue and prognosis

Detailed parental counselling
- Give the most possible & clear information to the family.
- Identify & discuss possible options & their potential consequences.
- If needed, take a second opinion.