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

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 268 AFRICA is situated in the rainforest belt. It is 122 m above sea level with an estimated population of 1 085 676 (2006 census). The UBTH is a 700-bed centre that provides primary, secondary and tertiary healthcare services to the entire Edo State and neighbouring states of Delta, Ondo and Kogi. Babies delivered vaginally and who are stable are discharged after 48 hours while those born by caesarian section are discharged after five days from the postnatal wards. This provides ample opportunity for their echocardiographic screening before they go home. The neonatal wards have a capacity for 50 beds. The annual birth rate in the UBTH is 2 000 births. Ethical approval was obtained from the ethics committee of the UBTH with protocol number ADM/E 22 A/VOL VII/1380. Written informed consent was obtained from parents/guardians of the newborns. This descriptive, cross-sectional study was carried out over 16 months (January 2017 to April 2018). The study participants were consecutive live newborns delivered in the UBTH and recruited from the postnatal and neonatal wards. All neonates were recruited irrespective of gestational age, APGAR score, maternal illnesses and mode of delivery. The neonates who fulfilled the following criteria were recruited for the study: all newborns admitted into the postnatal wards after delivery, all sick babies admitted into the neonatal wards including those with congenital anomalies, and all babies of mothers with acute or chronic illnesses. Neonates with the following criteria were excluded from the study: newborns with patent foramen ovale of ≤ 3 mm in size were not considered as significant CHD, and preterm newborns (< 37 completed weeks) with haemodynamically insignificant patent ductus arteriosus (PDA) were also not counted as having CHD. The following features characterised haemodynamically significant PDAs: those with PDA diameter > 1.5 mm, the ratio of left atrium:aortic diameter > 1.4, mitral valve E and A velocity ratio > 1, and those with flow reversal in the descending aorta. 10 Neonates with tiny muscular ventricular septal defects (VSDs) were equally excluded. The age at recruitment, gestational age, gender and birth weight of each neonate recruited for the study were documented. Other information that was sought for included parental age. The socio-economic status of the family was determined using the method described by Olusanya et al . 11 The maternal age was categorised into < 40 and ≥ 40 years, while the paternal age was categorised into < 50 and ≥ 50 years. A full clinical examination was carried out on each neonate with the emphasis on the cardiovascular system. The gestational age was determined by dates and early ultrasound where available. The babies were weighed using an infant weighing scale and the crown–heel length was taken in the supine position using a non-elastic tape. The gestational maturity was determined using the Dubowitz and Dubowitz method. 12 Each neonate after feeds, while lying quietly or asleep, had a screening echocardiogram using standard views including two-dimensional, M-mode, colour flow and spectral Doppler. Analysisof the reportwasdoneaccording tothe recommendations of the American Society of Echocardiography. 13 A Sonosite Micromaxx model with an 8-MHz probe was used to interrogate the heart from the apical, subcostal, parasternal and suprasternal views. The echocardiograms were done by the principal investigator who is trained in echocardiography. Each newborn diagnosed with CHD was referred to the paediatric cardiology unit of UBTH for a comprehensive echocardiographic study and further management, including preparing for surgical intervention if indicated. Statistical analysis All collected data were checked for completeness, coded and analysed using the IBM-SPSS version 20.0 (Chicago, Illinois). The birth prevalence of CHD was expressed as number per 1 000 live births. The difference in birth prevalence between types of CHD was tested with the Z -test. The relationship between variables such as gender, socio- economic class, parental age categories and the presence of CHD and its types was tested with the chi-squared test in a bi-variate analysis. The difference in mean values such as the mean gestational ages of newborns with different types of CHD was compared using the student’s t -test or one-way ANOVA where more than two means were compared. The level of significance was set at p < 0.05. Results A total of 2 849 babies were recruited during the study period. There were 1 482 (52.0%) males with a male:female ratio of 1.1:1. They were recruited between 24 hours and 18 days of life with a mean age of 2.2 ± 1.7 days. The mean weight was 2.85 ± 0.73 kg with a range of 0.25–7.5 kg. Their mean length was 46.94 ± 4.32 cm with a range of 26–65 cm. The mean occipitofrontal circumference (OFC) was 33.79 ± 2.84 cm and ranged between 20 and 56 cm. The details of the sociodemographic and clinical characteristics of the newborns are shown in Table 1. There were 2 438 fathers with available data on age. Of these, 2 361 (96.8%) were < 50 and 77 (3.2%) were ≥ 50 years. The maternal age ranged between 15 and 60 years with a median age of 31 years, while the fathers’ ages ranged between 18 and 71 years with a median age of 37 years. Of the 2 774 mothers whose ages were available, 2 617 (94.7%) were < 40 while 147 (5.3%) were ≥ 40 years. There were 41 newborns with CHD, giving a birth prevalence of 14.4/1 000 live births (95% CI: 10–18.8/1 000). Of the 41 Table 1. The demographic characteristics of the study population Characteristics Frequency Percentage Maturity ( n = 2 724) Term 2107 77.4 Preterm 594 21.8 Post-term 23 0.8 Gestational maturity ( n = 2 702) Normal for gestational age 2306 85.3 Large for gestational age 121 4.5 Small for gestational age 275 10.2 Birth weight categories ( n = 2 805) Normal birth weight 2195 78.3 Low birth weight 449 16.0 Very low birth weight 132 4.7 Extremely low birth weight 29 1.0 Socio-economic class ( n = 2 734) High class 1612 59.0 Middle class 619 22.6 Low class 503 18.4