Analysis Of Risk Factors In Congenital Heart Disease

Congenital heart disease(CHD) represents one of the most prevalent congenital malformation, with an incidence of 6-8‰among live births. In recent years, fetal echocardiogram(ECHO) has been become an effective technique in early screening and diagnosing CHD prenatally. As cardiac development has been completed in the first trimester of pregnancy, it is feasible to study the risk factors of CHD prenatally. Though some well designed population based studies have been conducted, to date, there are no published reports of large prospective studies examining environmental or nutritional factors associated with CHD in China.Objectives:To explore the risk factors of CHD by using fetal ECHO technique prenatally, to assess the effects in the occurrence of CHD and to provide a scientific basis for the prevention of CHD.Methods:The study was designed as descriptive prospective clinical epidemiologic study. Relying on the national 863 project, there are 12cooperative units join in this study, samples were divided into the non-Shanghai and Shanghai target population. The first part, from Jan.2009 through Dec.2009 for 12 consecutive months, by using fetal ECHO as the diagnostic criteria,1:1 matched case-control study was executed, in which 173 non-Shanghai fetal cases and controls' mothers were interviewed with the same questionnaire during pregnancy. The second part, from 11, May.2010 through 15,Oct.2010 for 5 consecutive months, using fetal ECHO, pathology and neonate ECHO as the diagnostic criteria,1:2 matched case-control study was conducted, in which 39 Shanghai cases and 78 Shanghai controls'mothers were interviewed with the same questionnaire during pregnancy. For statistic analysis, univariate conditional Logistic regression was used to filter the selective factors, then multivariate conditional Logistic stepwise regression to filter once more, to establish and evaluate the optimal regression model.Results: In the first part of study, positive life events, folic acid supplementation in periconception, passive smoking in pregnancy etc.18 suspicious risk factors entered the analysis of multivariate conditional Logistic stepwise regression after univariate conditional regression analysis of 59 factors (alpha=0.10). The analysis results showed that positive life events(OR=0.399), eating potatoes during pregnancy(OR=0.662), folic acid supplementation in periconception(OR=0.525) were protection factors of CHD, radiation exposure before pregnancy(OR=3.567) and indoor decoration in early pregnancy(OR=2.106) were risk factors of CHD. In the second part, using the same statistic methods, univariate conditional regression analysis showed 5 risk factors possibly associated with the occurrence of CHD, they were:threatened abortion, having cold without fever, using progesterone in pregnancy, weight gain<10% in the early 5 months of pregnancy. The multivariate conditional Logistic stepwise regression showed that weight gain<10% in the early 5 months of pregnancy(OR=0.236)was protection factor for the occurrence of CHD, threatened abortion(OR=3.47) was the associated risk factor of CHD.Conclusions:This study showed that the protection factors of fetal CHD diagnosed with fetal ECHO in non-Shanghai area were positive life events, eating potatoes during pregnancy and folic acid supplementation in periconception; the risk factors were radiation exposure before pregnancy and indoor decoration in early pregnancy. The protection factor of CHD in Shanghai diagnosed with fetal ECHO and other techniques was weight gain<10%in the early 5 months of pregnancy; the risk factor was threatened abortion. Though the casual relationship between risk factors and CHD needs further research, this study had prompted that environmental factors had a significant impact on the occurrence of CHD. In general, strengthening and promoting pregnancy health care remains the main task for the prevention of CHD.