This was a retrospective observational study which was conducted in the Department of Paediatrics of a tertiary care public hospital in Northern India from April 2016 to June 2019. Ethical committee clearance and consent was not taken as this was a retrospective review of records of data. Inclusion and exclusion criteria: Patients who were referred for foetal echocardiography were included in the study. Patients who had repeat foetal echocardiography during the period or those undergoing first trimester foetal echocardiography were excluded.

Foetal echocardiography was done on Philips XD 11 E machine with an S 2-5 curvilinear probe. Referred patients were divided into lower and higher risk groups. Lower risk pregnancies were defined as those pregnancies where the risk of the foetus having congenital heart disease was less than 1% as per the American Heart Association (AHA). Higher risk pregnancies were those which had more than 1% risk of having foetuses with heart disease [6]. After echocardiography, parents of foetuses with heart disease were explained about the nature of the cardiac lesion and the possible management options were discussed. They were then sent back to the referring Obstetricians. Children with complex and potentially serious heart disease were advised to conduct delivery of their child at a tertiary care cardiac centre. The actual delivery and postnatal management of these foetuses were done in different public sector hospitals, including our own hospital. All patients were advised postnatal echocardiography for confirmation of diagnosis. Data about the demography, indication, result of foetal echocardiography and outcome was retrieved from records.

Data was tabulated as mean (standard deviation), percentages and frequencies analysis was done in Microsoft Excel 2013.

There were a total of 1013 patients who underwent foetal echocardiography from April 2016 to June 2019 in the hospital. The age of mother and gestational age at the time of foetal echocardiography is shown in [Table/Fig-1]. Sixty four foetuses had abnormal findings. After excluding five foetuses with ductal constriction, there were a total of fifty-nine foetuses with structurally abnormal hearts.

711/1013, (70.2%) of the patients who were referred for foetal echocardiography were at low risk pregnancies while 29.8% were at high risk. The indications for referral and the number of foetuses with structurally abnormal hearts are tabulated in [Table/Fig-2,3].

The indication with the highest yield was abnormal heart seen in level two ultrasound, 76% of those who were referred for foetal echocardiography had structurally abnormal heart. Out of 51 such patients, 34 (66.7%) were referred because of an abnormality seen in the four chamber view and the remaining 17 were referred for an abnormal three vessel view.

Short term outcome data was available for 45 out of 59 patients. [Table/Fig-4] shows the variety of heart diseases diagnosed and their short term outcome till three months. Overall 28/45 (62.2%) of those who were antenatally diagnosed to have heart disease did not survive beyond the first three months.

Ideally, all children with congenital heart diseases, especially the ones requiring intervention in the first few months of life should have an antenatal diagnosis by foetal echocardiography. This will help the parents in planning the pregnancy, place of delivery and arranging the logistics so that the outcome of the foetus is improved.

In this study, the outcome of foetuses who had an antenatal diagnosis of heart disease were studied. The majority of patients were from low socio-economic strata. Delivery and subsequent treatment of foetuses/neonates/infants was done in different public sector hospitals in Delhi.

The ideal timing of foetal echocardiography is 18-22 week as per the AHA guidelines [6]. In the present study, most referrals were late. Among those detected to have structural heart disease, the mean gestational age at the time of foetal echocardiography was 28.4 weeks. Thus, most patients with structural heart disease had their antenatal diagnosis well beyond the legal time limit for medical termination of pregnancy. This pattern of late referral has been seen in previous studies from India [7-9].

Most referrals for foetal echocardiography (70.2%) in the present study had lower risk pregnancies. A 1.4% of the lower risk cases had heart disease compared to 16.2% of the higher risk cases. The AHA guideline states that foetal echocardiography is not indicated in those mothers who have lower risk pregnancies, which is defined as those pregnancies with less than 1% risk for heart disease in their foetus. However, in the present study, the majority of the subjects were from this lower risk group. This study reiterates the value of adhering to existing guidelines for referral as there was high yield of heart disease in the higher risk cases only.

Various studies from the west have documented the positive impact of prenatal diagnosis on specific types of heart diseases [10-12]. The heart diseases known to have been positively impacted due to pre-natal diagnosis are hypoplastic left heart syndrome, coarctation of aorta, transposition of great arteries and pulmonary atresia. Though one may think that antenatal diagnosis would help the foetus and ensure its survival, it is not always true. In a study published in lancet in 1999, half of the foetuses with antenatally diagnosed heart disease ended in termination of pregnancy in UK [13].

There are a handful of studies from India which have described the postnatal outcome of foetuses with antenatally diagnosed heart disease [Table/Fig-5] [1-5]. Most of these studies are from private tertiary care medical centres from Kerala. There is only one small study on this subject from a public hospital in North India. The patients attending a public sector hospital are generally of low socio-economic status and it is difficult for them to access neonatal cardiac care.

These previous studies show that, there is high rate of foetal loss in pregnancies with antenatally detected heart disease. The percentage of foetuses not surviving till term in previous Indian studies range form 27.8-78.6 [1-5]. In the present study, out of the 45 patients whose follow-up was available 11/45 (24.4%) did not result in live birth. Foetal losses are due to spontaneous abortions, intrauterine deaths and medical termination of pregnancies. Slightly lesser percentage of foetal loss in present study may be due to the fact that all diagnoses were made after the legal time limit of termination of pregnancy and hence medical termination did not contribute to the foetal losses.

In the present study, out of 34 live births, 17 (50.0%) died before three months of age with neonatal mortality of 41.1%. This was in contrast to previous studies where the mortality rate was lower than present study [1-5]. The percentage of death in the neonatal period in previous studies range from 14-17.8% [1-3]. One previous study has reported a mortality of 31% at one year whereas another has reported 39.5% mortality at a median follow-up of 10 months [4,5].

The poor postnatal outcome in present study reflects the complex nature of heart diseases as well as lack of access to timely cardiac interventional or surgical treatment to neonates and small infants with congenital heart disease. The outcome of neonate with heart disease depends upon a variety of factors including associated diseases, severity of heart disease, parental socio-economic status, access to care, and parental decision to continue cardiac care. In our study, all the parents of the affected newborns had the intention to continue cardiac care.

In the present study, out of the 17 newborn who died, eight were delivered in tertiary care paediatric centre, eight in a tertiary care cardiac centre and one was a home delivery. Out of these 17 infants, two infants with Ventricular Septal Defect (VSD) died of non-cardiac cause. One had birth asphyxia and another had undiagnosed trachea-oesophageal fistula, which was successfully operated. Subsequently, patient developed pneumonia and died due to pneumonia. None of the patients with a diagnosis of hypoplastic left heart syndrome, pulmonary atresia with intact septum, coarctation of aorta, Ebstein’s anomaly or transposition of great arteries survived beyond the first month. Out of the 34 live birth with heart disease, 24 required surgical or catheter intervention but only two patients underwent any surgery or intervention in the first three months of life. Both of these were neonatal BT shunt and out of these one survived. This is again in contrast to previous studies from Southern India where higher percentage (16.8-17.2) of newborns with heart diseases underwent interventions [1,2,5].

In the present setting, despite prenatal diagnosis, the outcome of foetuses which require early intervention is suboptimal due to complexity of diseases and lack of access to timely intervention. Only one public sector hospital in Delhi is routinely doing cardiac surgical or interventional treatment in neonates and small infants, more such centres are needed. Many private institutions are providing neonatal cardiac care but access to such care for people from low socio-economic status needs to be improved. Kerala has successfully implemented a program called Hridyam for children with heart disease. A web based registry was used to allocate children with heart disease to various public and private institutes for treatment according to the clinical priority [14]. Similar government program is needed in other parts of the country to improve the outcome of foetuses with antenatlly detected heart disease.

The limitation of this study was the small size, retrospective nature of the study and loss to follow-up of study subjects.

It is concluded from present study that, the referral for foetal echocardiography is frequently delayed and majority of referrals are of low risk cases. Earlier and more selective referral for foetal echocardiography is desirable. This will give the parents of foetuses with serious congenital heart disease adequate time to decide about continuing pregnancy versus opting for medical termination of pregnancy. In this study, the outcome of children with antenatally diagnosed heart disease was less than optimal. Infrastructure and manpower in public sector hospitals should be developed in order to cater to the children requiring intervention in neonatal and early infancy. Government health schemes should be designed such that timely intervention of neonates with heart disease is possible in both public and private sector hospitals.