Clinical presentation of CHD is versatile and is age-dependent, and hence, a higher index of suspicion is needed for early diagnosis and treatment [11]. In this study, the commonest presentation for CHD was the accidental discovery (35%) followed by recurrent chest infections (30.2%), cyanosis (16.7%), failure to thrive (13%), neonatal sepsis-like illness (3.3%), and finally shortness of breath (1.7%). In a study done by Otaigbe and Tabansi [3], indications for screening echocardiography were auscultation of a murmur (36%), rapid breathing (19.8%), failure to gain weight (11%), and cyanosis (9.9%), whereas in a study done by George and Frank-Briggs [11], fast breathing and inability to gain weight were the commonest presenting symptoms among CHD children.
Prevalence of murmurs is variable in different studies as it depends on the clinical skills, frequency, and timing of examination as nearly half of newborns with CHD will have no murmurs and possibly no other signs when examined at birth [12]. In this study, we detected audible murmurs in 74.4% of patients. Nearly 2 to 3 out of 1000 neonates with CHD will reveal symptoms during their first year of life. Diagnosis will be made by the first week in 40-50% and by the end of the first month in 50-60% of them [13]. In this study, most of our patients (86.8%) were diagnosed below the age of 1 year (37.8% in the neonatal period, and 49% within the first year of life). Similarly, in a study done by Subramanyan et al. [14], the ages at diagnosis of their CHD cases were in the early infancy and the neonatal periods in 40% and 38% of their studied population respectively.
In this study, we detected a male to female ratio of 1.2:1. This matches with previous studies [3, 15]. Isolated VSD was the most prevalent acyanotic CHD. This matches with most of the previous studies [3, 8, 15], whereas tetralogy of Fallot was the most frequent cyanotic CHD, which is also in agreement with most of the available studies [16,17,18].
CHD is the most common etiology for the occurrence of heart failure in infancy [19]. In the present study, we detected heart failure in 44% of the studied population. Similarly, Sommers et al. [20] detected heart failure in 39.1% of patients with CHD. The relatively higher prevalence of complications encountered in this study could be attributed to the lack of regular follow up and non-compliance to treatment, which eventually lead to the delay in surgical management.
About 15% of CHD cases could be related to an underlying genetic cause, and a smaller percentage could be attributed to an environmental modifiable risk factor [21]. According to Liu et al. [22], nearly 14% of CHD cases could be prevented by avoidance of exposure to all known risk factors; however, some recent studies detected a higher percentage of about 30% [21, 22]. Through this study, we tried to review the distribution of the perinatal risk factors-already known in literature among our studied population. This work was not designed to study them individually as predictors for the occurrence of CHDs; also, due to missing data in some files; not all the known risk factors were studied. This included maternal body mass index, smoking, anemia, nutritional status, and vitamin and folic acid supplementation during pregnancy.
In this study, the majority of our patients (91.7%) belonged to housewives. Different maternal occupations have been linked to CHDs [23]. Scientific research has not yet confirmed the association between maternal workplace exposure during pregnancy and the possible teratogenic effect on the forthcoming fetus, though there are still some concerns regarding exposure to pesticides, organic solvents, and heavy metals [24].
In Egypt, the prevalence of consanguinity is 29% [25]. The relation between consanguinity and the incidence of CHD had been explored in previous studies [26, 27]. We detected consanguinity and positive family history of CHD in 44.6% and 9.2% of our studied population, respectively. Similarly, Hag et al. [28] detected consanguinity and positive family history in 49% and 14% of their studied population, respectively, whereas Fung et al. [29] detected them in 3.5% and 21.8% respectively and detected 9% prevalence of CHD among first-degree relatives. Also, Nabulsi et al. [5] and AL–Ani [30] detected consanguinity rates of 34.7% and 77.9%, respectively. The differences among various studies reflect the differences in the prevalence of consanguinity among different societies. Moreover, the high-risk factor in closely related parents indicates that consanguinity may act as a genetic predisposition that increases the susceptibility of developing CHD, especially when there is exposure to an environmental risk factor. This highlights the need for public health education regarding the hazards of inbreeding.
In this study, one hundred and eighteen patients (11.7% of our studied population) were the product of assisted reproduction. Children conceived via modern technologies are thought to be at a higher risk for developing birth defects, including CHD [31]. Koivurova et al. [32] detected a fourfold increase in the incidence of CHD among fetuses conceived via in vitro fertilization (IVF). Also, Tararbit et al. [33] found a 40% increase in the risk of CHD among those children.
Chromosomal anomalies account for (8–10%) of syndromatic CHDs [34] with Down syndrome (DS) being the most common chromosomal anomaly seen among them [35]. In this study, syndromatic CHD was present in 16.7% of the studied population (62.5% of them were DS). Fung et al. [29] detected genetic and syndromatic CHD in 9.5% of their studied population. There is geographic variability in the type of the dominant cardiac lesion seen in DS among different countries [36]. In this study, the atrioventricular septal defect was the commonest lesion seen among DS (40.3%). This matches with Benhaourech et al. [37].
The pattern of maternal age as a hazardous factor for congenital defects differs among different countries which imply possible underlying genetic and environmental background rather than only the biological age [38]. Some studies suggested that the gynecological immaturity [39], lack of proper antenatal care, low socioeconomic class, poor diet, and other environmental non-biological factors account for birth defects among young mothers [40]. Other studies had observed the prevalence of CHDs among older mothers [41, 42], whereas Best and Rankin [43] failed to find a strong evidence to support that advanced maternal age is a risk factor for CHD. Older maternal age has been linked to chromosomal-related congenital abnormalities while the risk of maternal age on the non-chromosomal abnormalities is considered negligible [38]. In this study, most of our patients (91.3%) belonged to young mothers (< 29 years old), only 5.9% belonged to mothers older than 35 years at conception, and only 16.7% were associated with syndromatic and chromosomal abnormalities.
Various studies had shown the effect of maternal diabetes as a risk factor for fetal cardiac malformations [44], as well as maternal hypertension, cigarette smoking, and other maternal chronic illnesses [22]. In this study, maternal diabetes, asthma, hypertension, and epilepsy were found in 27.9%, 14.5%, 7.4%, and 4.2% of the studied population, respectively.
Though the exact etiological factors that link the association between increasing maternal parity and the risk of CHD is still unclear, theories include nutrient depletion especially folic acid [45], short inter-pregnancy periods [46], intrauterine exposure to teratogenic viruses (such as rubella) from children sharing the same home environment [47], biological changes in the intrauterine environment and psychological stress in pregnant mothers who are taking care of many children [48]. In this study, most of the patients (66.3%) were born to multiparous mothers, while 33.7% were born to nulliparous mothers. This matches with the meta-analysis done by Yu et al. [49].
In this study, abortions occurred in 7.1% of the studied population. In contrast to Li et al. [50] who failed to find an association between bad obstetric history, recurrent abortions, and the risk of CHD, Abqari et al. [6] detected such an association. Also, Feng et al. [51] found that mothers will have a 24% higher risk of cardiac anomalies in their children if they experienced repeated abortions before. Etiological arguments include possible uterine factors that influence the implanted embryo [52] and associated chronic maternal illnesses [53]. In this study, we also detected prematurity in 19.3% of our studied patients. Tanner et al. [54] found that preterm infants are 2-times prone to CHD when compared to term infants; they detected prematurity in 16% of their CHD patients.
Study limitations
This work was not designed to study the risk factors as predictors for the occurrence of CHD; instead, it aimed at detecting the frequency of occurrence of those risk factors already documented in literature—among our studied population. Moreover, due to missing data in files, not all the known risk factors were studied, such as maternal body mass index, anemia, nutritional status, antenatal vitamin, and folic acid supplementation. Furthermore, the exact antenatal timing of exposure to teratogen was also missing. In addition, many patients had more than one underlying possible risk factor.
Multi-centric similar studies are needed to be done in different governorates, different geographical areas, Upper and Lower Egypt, rural and urban areas, though we still believe that this study can be considered as a nidus for such studies as it was done in a large University tertiary referral center that receives patients from different geographical areas in Cairo Governorate including those critical, severe, and complicated cases that are neither managed in the Ministry of Health hospitals nor in the private sector.
