CHD is the most common group of congenital anomalies and a major cause of death in infancy and childhood . They are frequently required multiple hospitalizations and surgical procedures. Our study examined the epidemiologic features of CHD, using the data from the Guangdong Hospital-Based Birth Defects Monitoring System. We provide birth prevalence for CHD. In our study, all live births and still births born in monitoring hospitals were included and accessed within 7 days after delivery. So the prevalence of CHD in our study reflects the perinatal prevalence of CHD.
Our results showed that the prevalence rises in urban and rural populations during 2008–2012. There are might three reasons for that. First, the use of ultrasonic examination makes the rate of congenital diagnosis improved. In the lack of ultrasonic examination, the percentage of CHD was lower . In our study, we also found that the use of ultrasonic examination rises during 2008–2012 (data not shown). Second, with the improvement of congenital diagnosis, more and more CHD cases can be found in the perinatal period, resulting in an increasing prevalence. Parents accepted cardiac echocardiography as the most important neonatal screening method, and they were willing to screen their babies with cardiac echocardiography to determine whether CHD were present. Third, environmental and genetic factors can influence the prevalence of CHD.
The difference of maternal age-specific overall prevalence was observed in our study, and the prevalence in urban and rural areas increased with maternal age. A similar finding has been reported by Miller et al. , who reported that the prevalence in infants born to mothers older than 35 years was much higher than in those born to younger mothers. Other studies have showed that the prevalence of CHD increases with increasing maternal age [14, 18, 19].
In the birth defect registry system, the urban–rural classification depends on the place where the mother lived during the pregnancy, which mainly reflects the combined exposure during the pregnancy [18, 20]. In our study, we found a higher prevalence in urban areas compared with rural areas. The education, economic level, occupational exposure, lifestyle, and health care are different between people who live in urban and rural areas in China [21, 22]. On the other hand, living in rural areas may be associated with lower access to health care and a shortage of healthcare providers. The prevalence of CHD subtypes were also found to vary by urban–rural classification.
The data of our study is reliable and representative. The study was based on the birth defect registry system of the province of Guangdong, and the system contains 58 hospitals covering districts, which represents the total situation of CHD in Guangdong province well. All data were reported on the network in time. Strict quality control of data collection was taken by county, municipal and provincial experts every year, thus ensuring reliable data. However, several limitations in the study should be addressed. First, according to the surveillance system, the monitoring period was 28 weeks’ gestation to 6 days after delivery, and babies with CHD detected more than 7 days after delivery would be missed. Second, the study did not cover cases of births given out of hospital, although the proportion was small. Third, our study was difficulty in distinguishing between an ASD and a patent foramen ovale in the perinatal period. And because of most of foramen ovale and ductus arteriosus after birth to 6 days is normally patent and will be closed naturally within several months. The exclusion of a patent foramen ovale and patent ductus arteriosus in perinatal infants eliminated perinatal conditions from consideration, thereby improving the prevalence estimates of CHD. Finally, it is possible that hospital-based samples might introduce referral bias. However, our study used the data from the Guangdong Hospital-Based Birth Defects Monitoring System, which is covering 58 hospitals across the province, and our results provide value insights to our understanding of the main epidemiologic characteristics of CHD prevalence in Guangdong province.
The findings from our study have some practical implications. High prevalence of CHD indicates that CHD become one of the major public health concerns in Guangdong province, China. A high and increasing rate of CHD among perinatal infants increases the burden on families and health care providers, both in terms of parental anxiety, and of the direct costs of diagnostic examinations, follow-up, and possibly treatment .