Objectives: Prenatal detection of congenital heart disease (CHD) by using fetal echocardiography (FE) helps early diagnosis leading to prompt management and treatment. FE provides the high accurate non-invasive modality to improve the survival or life quality of CHD patients. The aim of this study was to evaluate the antenatal detection of CHD by FE and compare with post-delivery echocardiography results.

Method: A prospective cohort study of pregnant women referred to tertiary center Imam-Reza hospital, Mashhad, Iran for performing FE in hands of a skilled pediatric cardiologist between 2012 and 2021. Cardiac echocardiography was performed by GE Vivid 7 color Doppler and Mindray Resona 7 color Doppler with a convex probe 5-7 megahertz during late first trimester or early second trimester and after birth till 2-month later. Data was analyzed with SPSS and MedCalc software and agreement evaluated by using kappa.

Result: Out of 261 studied fetuses, 101 normal cases detected in total agreement with postnatal-echo diagnosis. Acceptable diagnosis found for Septal defects; VSDs high statically detected (sensitivity= 90%, specificity= 93%).
complex CHDs noted to be the mostly precise accurate prenatal diagnosis. Right Arch abnormalities, aortic stenosis, hypoplastic left heart syndrome and cardiac masses were completely acceptable but detecting coarctation of aorta faced with over-diagnosed. Prenatal diagnosed arrhythmias without structural defects mostly premature beats shifted to normal after-birth Echo.

Conclusion:
FE is a safe and sensitive modality in the prenatal diagnosis of CHDs. The study showed the effectiveness accuracy of early first trimester; also complete detection in both-side of defect spectrum.