Previous studies from different area in China have reported various incidence of CHD, which ranged from 6.87 to 76.00 per 1000 children.5, 18–23 To our best knowledge, this has been the first time that performed a prospective census-based cohort study investigating all local pregnant and their newborns to respectively evaluate incidence and type of CHD during fetal and neonatal period, and analyze the potential risk factors, which provides new knowledge of CHD control and prevention. Our study indicates that the incidence of CHD in fetuses is twice for that in newborns. Of the 64,763 participants, 1,026 (15.84‰) had fetal congenital heart disease. Of the 63,958 live births (including 114 newborns of missing birth record), 468 (7.32‰) newborns were diagnosed CHD. The highest incidence of fetal CHD is congenital tricuspid regurgitation accounting for 29.43% (304/1,026), followed by malformations of ventricular septal defect 26.71% (274/1,026). However, the highest incidence of neonatal CHD is ventricular septal defect 34.40% (161/468), followed by congenital tricuspid regurgitation 18.8% (88/468). The type with highest incidence in our study is consist with the previous reported by Egbe A, et al.5 However, the type with second high incidence is different, which is atrial septal defect detected by Egbe A. For this difference, the main reason maybe that isolated patent foramen ovale and patent ductus arteriosus are excluded in our study because they are normal neonatal findings during fetal and neonatal period. Compared with previous studies, our study could evaluate more accurate incidence of CHD on the basis of conducting the prospective census-based cohort study. The higher incidence of CHD in fetuses than newborns, indicates that prenatal screening and diagnosis are significantly important for CHD control and prevention. Moreover, our findings provide some important implications for the prevention and management of CHD. First of all, abortion and stillbirth should be extremely concerned for pregnant with critical CHD fetuses. Moreover, it should be avoided that pregnant with light and mild cardiac abnormality select termination. Last but not least, even if fetuses identified as CHD, they still have a chance to become health when they are born, due to the subsequent development of tissues and organs. Overall, fetal CHD screening is very important for the early detection and intervention of CHD.
As previous studies have suggested, the variation in CHD incidence was attributed to cases of minor CHD, but severe CHD remained stable.4 In our report, 114 of 1,026 pregnant women with fetal CHD chose to terminate their pregnancy. CHD classified as simple, moderate, complex. Among these terminated cases, sample CHD cases, moderate and complex CHD accounted for 24.56% (28/114 fetuses), 17.54% (20/114 fetuses), 49.12% (56/114 fetuses) respectively. 10 of 114 terminated cases were cardiac abnormal but not identify the type of fetal CHD. Meanwhile, the vast majority of fetuses with congenital tricuspid regurgitation are more likely to repair itself when they are born, as well as about half of fetuses with ventricular septal defects. Additionally, there were 42 newborns with CHD who have no cardiac abnormality during the fetal period. It indicated that the screening of fetal echocardiography in CHD may cause missed diagnosis and overdiagnosis, which may lead to over induction. In our country, most pregnant women and families lack of the knowledge of CHD, reacting strongly to CHD in pregnancy, and eventually chose to give up due to severe psychological burden. Actually, several induction cases including congenital tricuspid regurgitation, small ventricular septal defects and left superior caval vein, maybe self-heal or effectively cured by surgery in later stage, and do not affect quality of life. For these pregnant with fetal CHD, the ethics committee should strengthen management and strictly control the blind choice of induction.
We observed that pregnant women who have given birth to a child before have effect on the occurrence of CHD have less risk of having CHD in their offspring in comparison to the pregnant women who has never had a child before. (RR: 0.890; 95% confidence interval, CI, 0.813–0.975). We suspected that pregnant women who have given birth to a child before have more experience to take care of themselves in terms of diet, health and pre-pregnant check during pregnancy. Those pregnant women or their relatives had history of congenital heart disease increase odds ratio of having CHD in their offspring (RR, 2.480; 95% CI, 1.362–3.967), which is similar to the study done by Yokouchi-Konishi T, et al.24 Some studies showed no association between maternal education level with CHD.25 However, others have found that the occurrence of CHD was inversely associated with the mother’s education level, and that there was a dose–response relationship between them.26 In our study, as compared with maternal educational level group less than high school degree, in maternal educational level group high school or college degree, odds of having CHDs is 1.342 (RR, 1.390;95% CI, 1.129–1.701). In China today, adolescents are becoming much more sexually liberated.27 Premarital sex and unplanned pregnancies among teenagers are increasing, especially in the group of high school degree or college degree, thereby indirectly raising the occurrence of CHD. These findings also highlight the need to improve the healthcare and sex educational opportunities for teenagers, particularly for those with high school or college education. We found that those pregnant women who live in countryside induce odds ratio of having CHD in their offspring (RR, 0.821; 95% CI, 0.730–0.920). The main reason may be the complex industrial/urban scenario emission such as SO2.28 If pregnant women are influenced by environmental factors during this period (early trimester of pregnancy), the fetus easily suffers from CHD. In this study, we conduct a prospective cohort study of pregnant women and find that the odds of having CHD to be 1.214 (RR, 1.215;95% CI, 1.080–1.359) with a history of illness in 1st trimester, which is similar to the study done by Liang Q, et al.29 Poisson regression analysis indicated that twin and multi-fetal infants are more likely to suffer from CHD than singleton infants (RR: 1.631, 95% CI: 1.276–2.036). The study can examine the risk of CHD in twins compared with singletons. This is consistent with the study done by Best, K. and J. Rankin.30 Our study found that the relative ratio of having CHD to be 1.780 (95% CI, 1.300-2.345) with birth defect in the firstborn child. The results indicate that the increased risk of CHD not only associate with the history of having a CHD sibling, but also with the history of having a birth defect sibling. Possible explanations for increased CHD risk in siblings of children with birth defect include shared genes, shared environmental factors, or a combination.31
Due to the registration process of the total pregnant women in Qingdao, we need multi-center cooperation to complete information collection throughout their pregnancy. There are more than 60 prenatal ultrasound institutions and many ultrasound physicians in the city. Owing to the widely different levels of experience of examiners, there is a large discrepancy in study results of second trimester ultrasound screening for fetal malformations, which is a result of varying levels of obstetric scanning expertise prevalent at the reporting center.