A total of 598 severe heart defects were diagnosed in a study population of 175,153 live births occurring between 2009 and 2018. CHDs mostly (70%, 419/598) manifested as isolated anomalies. A concomitant genetic disorder was diagnosed in 20% (120/598) of the cases, and extracardiac pathology with a normal karyotype was present in 10% (59/598) of the cases. In total, 47% (282/598) of all CHDs were not identified prenatally (Table 1). The percentages of prenatally unidentified cases for the different CHDs were as follows: ventricular septal defect, 72% (72/100); atrioventricular septal defect, 29% (19/65); coarctation of the aorta, 58% (33/57); transposition of the great arteries, 44% (24/55); tetralogy of Fallot, 37% (20/54); persistent ductus arteriosus, 100% (46/46); hypoplastic left heart syndrome, 9% (4/45); pulmonary stenosis, 44% (17/39); double outlet right ventricle, 38% (14/37); aortic stenosis, 37% (12/32); pulmonary atresia with ventricular septal defect, 25% (3/12); common arterial trunk, 45% (5/11); Ebstein’s anomaly, 45% (5/11); tricuspid atresia, 20% (2/10); single ventricle, 12% (1/8); pulmonary atresia with intact ventricular septum, 0% (0/6); interruption of the aortic arch, 50% (2/4); corrected transposition of the great arteries, 0% (0/3); and total anomalous pulmonary venous return, 100% (3/3).
Among the newborns with prenatally undetected CHD, 52% were males (147/282). The median age of the mothers having newborns diagnosed with CHDs was 29 (range 16–46). In total, 15% (42/282) of the mothers had a history of risk factors. The most common (38/282) maternal diseases were pregestational diabetes, hypertension, thyroid disease, rheumatic and autoimmune disease, oncological disease, and haematological and coagulation disorders. In 4 cases, the mother herself was treated for moderate or severe CHD. Vaginal birth occurred in 63% (177/282) of the children born with CHDs, and there was no significant perinatal asphyxia, even in critical cases. Details of the perinatal period, and gender are given in Table 1. The most common CHD was a ventricular septal defect, and the least common was a single ventricle. The group of cyanotic defects included 83 cases, while the group of acyanotic defects included 199 cases.
Time of diagnosis
A total of 74% (209/298) of the children with CHD were diagnosed as early neonates, usually during their stay at the maternity hospital (Table 2). In 100% of the cases, the following defects occurred at this early age: transposition of the great arteries, tetralogy of Fallot, common arterial trunk, interruption of the aortic arch, hypoplastic left heart syndrome, pulmonary and tricuspid atresia, and single ventricle. Coarctation of the aorta and Ebstein’s anomaly were the least frequent diagnoses in the earliest period, which in one third of the cases were manifested in the late neonatal period when the newborn was discharged from the maternity hospital. Diagnosis after discharge occurred in 26% (72/282) of the hospitalised prenatally undetected cases and in 12% (72/598) of all major CHDs. In infancy, the finding of ventricular septal defect, pulmonary stenosis, coarctation of the aorta, and Ebstein’s anomaly exceeded 10%, and these defects had a greater risk of late detection in infancy than other major CHDs (18% versus 3%, p < 0.001). All defects except isolated cases of ventricular septal defect and persistent ductus arteriosus were diagnosed by 6 months of age.
As expected, when newborns were divided into two groups based on the presence of cyanotic and acyanotic defects, those with cyanotic defects had earlier manifestations [early neonatal: cyanotic 95.2% (79/83) vs. acyanotic 65.8% (131/199); late neonatal: cyanotic 2.4% (2/83) vs. acyanotic 21.1% (42/199), early infancy: 2.4% (2/83) vs 11.6% (23/199), late infancy: 0% vs 1.5 % (3/199), p < 0.0001]
Symptoms leading to diagnosis
The most common symptoms leading to the diagnosis of CHD were heart murmur and cyanosis (Table 3). Cyanosis was the most common symptom in the group of cyanotic defects including transposition of the great arteries, tetralogy of Fallot, interruption of the aortic arch, hypoplastic left heart syndrome, total anomalous pulmonary venous return, common arterial trunk, and pulmonary and tricuspid atresia. Heart murmur was the most common symptom in the group of acyanotic defects including ventricular and atrioventricular septal defects, coarctation of the aorta, and pulmonary and aortic stenosis; and in the group of cyanotic defects including double outlet right ventricle and Ebstein’s anomaly. Cyanosis was logically significantly more common in the group of cyanotic defects [cyanotic 64% (53/83) vs. acyanotic 8% (16/199); p < 0.0001], while heart murmur was significantly more common in the group of acyanotic defects [cyanotic 29% (24/83) vs acyanotic 63% (155/199), p < 0.001].
Circulatory instability and circulatory shock were most common in persistent ductus arteriosus cases due to immaturity and neonatological complications. Respiratory complications were the main symptom in 10–20% of the cases with coarctation of the aorta, aortic stenosis, total anomalous pulmonary venous return, and common arterial trunk. The highest rate of failure to thrive (15%) upon CHD diagnosis occurred in coarctation of the aorta. In this defect, finding of a weakened pulse on the femoral arteries contributed to diagnosis in only 9% of the cases. Stigmatisation due to genetic abnormalities contributed the most (26%) to the diagnosis of CHD in atrioventricular septal defect. Rarely, a diagnosis of CHD was made in the follow-up for other organ pathologies, most notably in cases of double-outlet right ventricle. Except for cyanosis and murmur, the incidence of symptoms between study groups differed in failure to thrive [cyanotic 0% (0/83 vs. acyanotic 5% (10/199), p < 0.037] and circulatory instability [cyanotic 0% (0/83) vs acyanotic 12% (24/199), p < 0.001], both of which were more common as a main symptom in the group of acyanotic lesions. For the remaining symptoms (dyspnoea, tachypnoea, weakened femoral arteries, and other organ disability), no difference was identified between the groups.