It is thought that 85–90% of CHD cases are multifactorial (which result from an interaction of genetic and environmental factors). In approximately 8% of cases, a congenital heart anomaly can be associated with a genetic defect; however, in most cases, a genetic etiology cannot be determined [4].
It has been reported that there is a relationship between some anomalies and gender. In our patients there was a slight female preponderance (52,6%). The reason why acyanotic anomalies are more common in girls is the presence of anomalies such as VSD, PDA, ASD in this group, and these data are consistent with the information in the literature. It has been reported that spontaneous septal defect closure is more common in males than females [5]. According to a meta-analysis, the female gender is a risk factor for the presence of CHD in Down Syndrome [6]. On the other hand, there are studies reporting cyanotic anomalies being more frequently detected in males [2]. Biological gender differences in the structure of blood vessels and androgenic hormones may be responsible for gender differences in this regard [7].
Although the subjects included in the study presented due to reasons such as respiratory distress, cyanosis, familial risk factors or for routine examination, the most common reason for admission was cardiac murmur. Sixty-four (54.3%) patients presented with a murmur. In previous studies, the most common reason for cardiological consultation was also cardiac murmur [8, 9].
In the study of Aydoğdu et al., VSD was the most common anomaly with a prevalence of 42.9%, and ASD was in the second most common anomaly with a prevalence of 37.5% [10]. In our study, VSD was the most common anomaly (39.5%) followed by ASD (12.2%), a finding which was partly consistent with the literature. The most common cyanotic anomaly was teratology of fallot (10 patients; 8.7%); tricuspid atresia was found in 5 (4.3%) patients, and TGA in 6 (5.2%). The fact that 4 of these 6 patients were male is in accordance with literature data indicating that serious and complex heart defects are more common in males [2].
In our study, consanguinity was found between the parents of 28 (24.5%) patients; It was determined that there was first-degree consanguinity among the parents of 18 patients (15.7%), and distant consanguinity between the parents of 10 patients (8.8%). In a study conducted by Güven et al. [11] in 2002–2003 on CHD in newborn clinics, it was found that 15% of infants with CHD had a family history of consanguineous marriage between their parents, with most of these relationships being first-degree consanguinity. Having a higher rate of consanguinity, 15.7% of our patients’ parents were first-degree relatives. These data are partly consistent with the data on first-degree consanguineous marriage in the study of Güven et al., which suggests that first-degree consanguineous marriage may be influential in the etiology of CHD.
The recurrence risk for CHD increases two- to threefold when there is a family history. This shows that CHD can be transmitted by Mendelian inheritance [12]. In the literature, it has been shown that having CHD in the family is a risk factor for CHD in subsequent children [13]. In our study, 6 (5.2%) patients had a history of CHD in their relatives, 4 (3.5%) in their siblings, and 5 (4.3%) in their parents.
Congenital heart disease is seen more frequently in some single gene defects and chromosomal abnormalities; for example, approximately 40% of children with Down Syndrome have overt heart disease, 50% of which can be congenital heart diseases such as endocardial pillow defect, VSD, PDA, and TOF [14]. In our study, a chromosomal anomaly was found in 9 (7.9%) patients. Of these patients, 5 had Down Syndrome, 2 had Di George Syndrome, 1 had Turner Syndrome and 1 had Edward Syndrome. In a study by Park et al., endocardial cushion defect (43%) was the most common anomaly in patients with Down syndrome, followed by VSD (32%) [15]. In a study by Meberg et al. [16], Edwards Syndrome was detected 2.1% (58%), in the study of Dorfman et al. 0.5% [9]. In our study, Edwards Syndrome was found at a rate of 0.87%. In Down syndrome patients, there is overexpression of the DSCAM (Down syndrome cell adhesion molecule) gene that creates an imbalance in the epithelial-mesenchymal transformation that leads to a defect in mesenchymal migration and proliferation that causes CHD [17].
Compared to normal babies born in the same gestational week, low-birth-weight babies are more likely to have ASD, VSD, tetralogy of Fallot, hypoplastic left heart syndrome, pulmonary stenosis, or aortic coarctation {18,19]. In a study performed by Kadivar et al., the mean gestational age was 38 weeks, the mean birth weight was 2812 g, and the number of prematurity was 41 (16.9%) [8]. In the study of Aydoğdu et al., the mean birth weight was 2961 g, and 18% of the cases were prematüre [9]. In our study, 26 (22.8%) patients were preterm, 17 (14.9%) were low birth weight (under 2500 g), and the mean birth weight was 2.982+/ -740 g. The high rate of low-birth weight and high mean maternal gestational age suggests that these two factors may be influential in the etiology of CHD. Besides comorbidities are also effective risk factors. Maternal diabetes increases the incidence of congenital heart disease. If the mother has insulin-dependent diabetes mellitus, anomalies such as VSD, TOF and great vessel transposition may develop. In the study of Kadivar et al. [8], 9% of patients diagnosed with CHD were born to diabetic mothers. In our study, 6 of the patients (5.2%) had a maternal history of insulin-dependent diabetes mellitus, 2 (1.8%) had a maternal history of hypertension and antihypertensive drug use, and 4 (3.5%) had a maternal history of preeclampsia. Both maternal hypertension and diabetes affect maternal metabolism and cause endothelial dysfunction, which leads to CHD.
It has been shown that folic acid deficiency increases the risk of cardiovascular anomalies in the fetus [20]. Therefore, it is recommended that folic acid supplements be administered to mothers starting one month prior to pregnancy and for two months after the start of pregnancy [20]. In our study, although the mothers of at least 57 (50%) patients regularly used iron, folic acid, and multivitamins during pregnancy, it was determined that many mothers either used folic acid irregularly or did not use it at all.