Prevalence and distribution of structural heart diseases in high and low risk pregnancies

Objective: To establish and compare the frequency of intrauterine congenital heart defects in high-risk and low-risk pregnancies for congenital heart diseases. Methods: Records of 3782 patients who underwent fetal echocardiography at the Pediatric Cardiology Unit were reviewed for reasons of refer- ral and results of echocardiography retrospectively. The categorical variables between the groups were analyzed using a Chi-square test. Results: Structural heart defects were found in 213 (5.6%) fetuses in both high and low risk groups. Most common defects were ventricular septal defect (36.2%) and atrioventricular septal defect (14.1%). Frequency of congenital heart diseases was 7.8% (169 fetuses) in high-risk group: 4.1% were complex, 2.3% significant and 1.4% were minor. In low-risk group, the frequency was 2.7% (44 fetuses): 0.6% were complex, 0.8% significant and 1.3% were minor. In this group, rates of congenital defects were high regarding particular reasons: intrauterine fetal death in previous pregnancy (6.3%), abnormal first or second trimester screening tests (4.3%), and multiple gestations (3.4%). The sensitivity and specificity of fetal echocardiography according to transthoracic echocardiography were found to be 86% and 99%, respectively. Conclusion: Congenital heart diseases rate, as expected, was found to be higher in high-risk group. However, regarding intrauterine fetal death in previous pregnancy, abnormal first or second trimester screening tests and multiple gestation, no statistically significant difference was observed between low-risk and high-risk groups. Therefore, we suggest the routine use of fetal echocardiography in cases we have mentioned above if the staff and equipment of the pediatric cardiology clinic are eligible.