Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 AFRICA 269 newborns, 21 (51.2%) were male and 20 (48.8%) were female. Thirty-six (87.8%) had acyanotic CHD while five (12.2%) had cyanotic CHD. The commonest CHD was isolated VSD, which comprised 11 (26.8%) of the CHDs. Transposition of the great arteries [TGA, 3 (7.3%)] was the most prevalent cyanotic CHD. There were five (12.2%) cases of mixed CHD with a prevalence of 1.8/1 000 live births (95% CI: 0.2–3.4/1 000). The mixed CHD consisted of one case each of VSD + ASD (atrial septal defect), ASD + PDA (patent ductus arteriosus) and VSD + ASD + PDA and two cases of VSD + PDA. The distribution of the other CHD cases is shown in Table 2. Five (12.2%) of the CHD cases were severe CHD, giving a prevalence of 1.8/1 000 live births (95% CI: 0.2–3.4/1 000). There was one case each of tetralogy of Fallot (TOF) and persistent truncus arteriosus (PTA) and three cases of TGA. Seventeen patients (41.5%) had minor CHDs constituting 6.0/1 000 live births (95% CI: 3.2–8.8/1 000). One neonate had dextrocardia but with no associated CHD. Babies with CHD were significantly lighter in weight than those without CHD ( p = 0.001). The mothers of babies with CHD were significantly older than those without CHD ( p = 0.038) and similarly, the fathers of babies with CHD were significantly older than fathers of babies without CHD ( p = 0.016). The difference in mean values of the length, occipitofrontal circumference (OFC) and gestational age between babies with CHD and those without CHD are shown in Table 3. Of the newborn variables evaluated for their relationship with CHD, low-birth-weight babies had significantly more cases of CHD than babies with normal birth weight ( p = 0.31). Similarly, post- and preterm babies had significantly more CHDs than term babies ( p = 0.0019). The details of the relationships between newborn and parental variables with CHD are shown in Table 4. Although there were no genetic studies done, 12 babies had clinically diagnosed Down syndrome, representing an incidence of 1:237 live births. Discussion The birth prevalence of CHD of 14.4/1 000 live births in this study is higher than the reported range of 4.5–9.4/1 000 live births in a meta-analysis of global birth prevalence from articles published in 2010 and earlier. 1 The birth prevalence is however comparable to the 13.8/1 000 live births obtained from the birth registry of CHD in Castellon province of the Valencia region 14 of Spain, and the 13.7/1 000 live births recorded as the overall birth prevalence in Norway. 15 These high values speak to the ability of echocardiographic screening to accurately identify children with CHD even though some of the CHDs may be clinically silent. The birth prevalence in this study is higher than the 8.07/ 1 000 live births recorded in a similarly conducted study in North India. 16 The difference in prevalence is mainly due to exclusion of a large number of minor CHDs in the Indian study. For instance, ASDs ≤ 5 mm in dimension were excluded, whereas in our study, those ≤ 3 mm were excluded, allowing more cases in our study to be recruited, with the attendant higher birth prevalence. While the overall prevalence in this study is high, the prevalence of severe CHD of 1.6/1 000 live births is low and consistent with other previous studies. The implication of this is that the observed increase is caused by minor and asymptomatic CHDs of septal defects and PDA. Similar findings have been noted in other studies, further emphasising the advantage of echocardiographic screening. The most prevalent CHD was isolated VSD, followed by isolated ASD. This finding is in agreement with other previous studies that showed VSD to be the most prevalent CHD and acyanotic CHD sub-group. 1,14,15 The commonest cyanotic CHD in this study was TGA. This is similar to some previous Table 2. Distribution of CHD by gender in the study population Types of CHD Male, n (%) Female, n (%) Total Isolated VSD 7 (63.6) 4 (36.4) 11 Isolated ASD 2 (28.6) 5 (71.4) 7 Isolated PDA 3 (60.0) 2 (40.0) 5 Isolated AVSD 2 (40.0) 3 (60.0) 5 TGA 1 (33.3) 2 (66.7) 3 Common atrium 0 (0.0) 2 (100.0) 2 Cor triatriatum 1 (100.0) 0 (0.0) 1 PTA 1 (100.0) 0 (0.0) 1 TOF 0 (0.0) 1 (100.0) 1 Mixed CHD 5 (100.0) 0 (0.0) 5 VSD = ventricular septal defect, ASD = atrial septal defect, PDA = patent ductus arteriosus, AVSD = atrioventriculoseptal defect, TGA = transposition of the great arteries, PTA = persistent truncus arteriosus, TOF = tetralogy of Fallot. The breakdown of mixed CHD is in the text. Table 3. Comparison of means of some variables between babies with and without CHD Variable CHD Mean (SD) No CHD Mean (SD) t -test p -value Birth weight (kg) 2.57 ± 0.75 2.87 ± 0.73 2.61 0.009* Length (cm) 46.4 ± 4.3 47.1 ± 4.3 1.03 0.300 Occipitofrontal circumference (cm) 34.0 ± 3.6 33.8 ± 2.8 0.45 0.65 Gestational age (weeks) 36.4 ± 3.6 37.4 ± 3.3 1.92 0.055 Maternal age (years) 33.1 ± 4.8 31.5 ± 4.9 2.08 0.038* Paternal age (years) 39.5 ± 6.2 37.4 ± 5.5 2.44 0.016* *Indicates significant values. Table 4. Distribution of CHD by neonatal and parental characteristics Variable CHD n (%) No CHD n (%) Total p- value Gestation ( n = 2 724) Term 22 (1.0) 2085 (99.0) 2107 0.009 Preterm 18 (3.0) 578 (97.0) 594 Post-term 0 (0.0) 23 (100.0) 23 Gestational maturity ( n = 2 848) Normal for gestational age 31 (I.3) 2275 (98.7) 2306 0.106 Large for gestational age 1 (0.8) 120 (99.2) 121 Small for gestational age 8 (2.9) 267 (97.1) 275 Birth weight categories ( n = 2 805) Normal birth weight 24 (1.1) 2171 (98.9) 2195 0.0043 Low birth weight 14 (3.1) 435 (96.9) 449 Very low/extremely low birth weight 2 (1.2) 159 (98.8) 161 Maternal age categories ( n = 2 774) < 40 years 36 (1.3) 2591 (98.7) 2627 0.0010 ≥ 40 years 5 (3.4) 142 (96.6) 147 Paternal age categories ( n = 2 438) < 50 years 34 (1.4) 2327 (98.6) 2361 0.21 ≥ 50 years 3 (3.9) 74 (96.1) 77 Socio-economic class ( n = 2 734) High class 21 (1.3) 1591 (98.7) 1612 0.27 Middle class 7 (1.1) 612 (98.9) 619 Low class 11 (2.1) 492 (97.8) 503