The principal of ultrasound scan is used for this technique. All aspects of ultrasound imaging (2D/3D/4D, M-mode and color Doppler) are used. A minimum requirement screening the fetal heart is a combination of 4 – chamber view (heart chamber, valve and partitions) and the outflow tract view (blood vessels) which enables most of the cardiac defects to be detected (a simplified 2 – view technique). A basic level heart level heart scan can be done by most of the sonologist who are adept in doing pregnancy scans. However, a detailed heart scan requires a highly specialist training and advance ultrasound machines. More importantly, the person doing the specialized heart scan should have a thorough knowledge about the various types of birth defects of the heart and treatment that can be offered including the cost involved. Such facility is called a specialized fetal cardiology unit. Very few centres in India have a specialized fetal cardiology unit. Which provides a comprehensive facility for diagnosis, counselling and then treatment for various birth defects of the heart.

With advance in ultrasound, accurate diagnosis of major cardiac defects can be done as early as 14 weeks of gestation. The ideal timing of fetal heart scan would be around 16 to 18 weeks. It is preferable to conduct these scans before 20 weeks (legal upper limit per medical termination of pregnancy). So that if a problem is diagnosed, the family can be offered all possible options for management.

A Basic heart scan (4 chamber and outflow views) should be compulsorily done as a part of every single obstetric scan. However, certain high risk pregnancies (as detailed below) should be referred for a detail fetal echocardiography. Such high risk pregnancies should be referred at around 16-18 weeks gestation.

Indication for echocardiogram:

• Previous child with congenital heart disease.
• Abnormal fetal heart in routine obstetric ultrasound.
• Irregular fetal cardiac rhythm.
• Hydrops foetalis or increased nuchal fold thickness.
• Major abnormalities of the other organ detected in the antenatal scan.
• Chromosomal anomalies of the foetus.
• Maternal diabetes or exposure of the mother to harmful medicines or toxins.
• Maternal auto-immune disease.
• Babies conceived by in-vitro fertilisation (IVF) or intra-cytoplasmic sperm injection (ICSI).

In the current era, it is extremely importantly to screen the fetal heart using a combination of 4 – chamber and outflow views in all pregnancies and refer all suspected cases for a more expert evaluation. Once a cardiac lesion is diagnosed, a multi-disciplinary approach is required to provide adequate counselling and then to manage the condition through the perinatal period.

Prenatal diagnosis of these defects in early pregnancy (<20 weeks) provides the following option for the family.

• In-utero transport of the foetus to cardiac centre: Here the pregnant mother is referred for delivering the baby with critical heart disease in a specialized cardiac centre. The baby can then be attend by an expert immediately after birth and treatment can be instituted without delay. Thus, the baby can be up for surgery before it becomes sick and sustains internal organ damage. Such an approach will certainly improve results of surgery, especially the neurological outcomes.
• In-utero treatment: This is particularly applicable in rhythm disorders where certain medicines are given to the mother to control the baby’s heart beat. (Fast as well as slow heart beat). In selected centres in-utero heart interventions (dilatation of the narrow valves) is also undertaken.

Some defects have important syndromic association, which maybe possibly detected in the intrauterine life and this would help the parents in taking a well informed decision.

Performing the fetal echocardiogram can help to mentally prepare the prospective parents. It would also help them to arrange finance in case of a neonatal surgery or intervention. Similarly the babies can be transferred to a unit performing these complex surgeries in a hemodynamic stable condition.

Fetal echocardiography uses the common ultrasound principle and it has been shown without any doubt that is very safe, even if performed multiple times, in pregnancy.

Babies with congenital heart defect require meticulous diagnosis, surgery and post-operative care. This is usually done by a team of doctors consisting of a paediatric cardiologist, paediatric cardiac surgeon, paediatric cardiac anaesthetist and paediatric cardiac intensive care specialist.

We also offer training facilities for those medical professionals who are interested in learning the art of fetal heart scan. We plan to have these courses once every 3 months.