Congenital heart disease (heart diseases from birth) accounts for approximately 50% of all deaths attributed to lethal malformations in children. With increasing advancements in the field of science, it is now possible to detect cardiac diseases in the fetus (when the child is within the mother) with remarkable accuracy and offer treatment for many critical heart lesions within the mother's womb.

When a routine ultrasound is performed during pregnancy, a four-chamber view of the fetal heart is routinely obtained. However, a four-chamber view of the fetal heart does not reliably detect conotruncal abnormalities. Most studies have retrospectively evaluated the accuracy of the four-chamber view for the diagnosis of congenital heart disease. Sensitivities between 10-20% reported in prospective studies of the four-chamber view indicate that all patients with any risk factor for congenital heart disease should be referred for a detailed foetal echocardiographic study.

Foetal echocardiography or ultrasound examination of the foetal heart recommendations include the following:

Indications for a foetal echocardiogram:

• Abnormal appearing heart on general foetal ultrasound
• Foetal tachycardia, bradycardia, or persistent irregular rhythm on clinical or screening ultrasound examination
• Maternal or family risk factors for cardiovascular disease, such as parent, sibling, or first relative with congenital heart disease
• Maternal diabetes mellitus
• Maternal Systemic lupus erythematosus
• Teratogen/Drug exposure during a vulnerable period
• Other foetal organ system anomalies detected in the foetus (including chromosomal)
• Performance of transplacental therapy or presence of a history of significant but intermittent arrhythmia. Reevaluation examinations are required in these conditions
• Foetal distress or ventricular dysfunction of unclear etiology

Possible indications for a foetal echocardiogram:

• Previous history of multiple foetal losses

When to do a foetal echocardiogram?

A foetal echocardiogram is ideally done at 18-20 weeks of gestation. This timing also allows for a repeat examination when the first examination is incomplete before 22 weeks (the maximum time limit for the termination of pregnancy). Serial examinations are recommended if a diagnosis of a cardiac defect is made, and the pregnancy is continued. Foetal echocardiography has been reported to have high accuracy when performed by experienced individuals. It is an extremely safe test with no radiation involved.

With increasing advancements in scientific technology, there is now the capability to not only diagnose the illness within the womb but also timely treat certain critical illnesses like the narrowing of valves (aortic and pulmonary) within the mother's womb. These lesions, if detected and treated in time, prevent the progression of the foetus to hypoplastic left heart or hypoplastic right heart syndrome (both with very poor long-term outcomes). Other cardiac diseases that can be treated in utero include restricted PFO and intractable foetal arrhythmias. It is important to recognize these lesions timely so that appropriate therapy, if timely instituted within the mother's womb, leads to the delivery of a healthy baby."