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

To establish and compare the frequency of intrauterine congenital heart defects in high-risk and low-risk pregnancies for congenital heart diseases.

Records of 3782 patients who underwent fetal echocardiography at the Pediatric Cardiology Unit were reviewed for reasons of referral and results of echocardiography retrospectively. The categorical variables between the groups were analyzed using a Chi-square test.

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.

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.