Reference Ranges and Clinical Significance of Key Fetal Cardiac Parameters Measured by Color Doppler Ultrasound at 11+0 to 16+0 Weeks of Gestation

Abstract Objective: This study aims to investigate the application value of four parameters, namely, V-angle (VSA), cardiothoracic ratio (CTR), global sphericity index (GSI), and cardiac axis (CAx), in the early detection of congenital heart disease (CHD) during the first trimester by using color Doppler ultrasound and increase the accuracy of CHD prediction in early pregnancy. Methods: A prospective study was conducted from January 2022 to March 2024 across two centers: Haidian District Maternal and Child Health Hospital in Beijing and Fujian Maternal and Child Health Hospital. A total of 2,529 normal fetuses and 50 fetuses with CHD underwent color Doppler fetal echocardiography between 11+0 and 16+0 weeks of gestation. The correlation between each parameter and gestational age (GA) during early pregnancy was analyzed. Normative reference ranges and diagnostic models were established and validated. The diagnostic efficacy of the four parameters for CHD was quantitatively assessed based on the established models, and their clinical application value was explored. Results: In normal fetuses during early pregnancy, GA showed negative correlation with VSA, positive correlation while CTR and GSI, and no correlation with CAx. Z-score models and reference ranges for the four parameters were established across five different GA groups. The polynomial linear regression model significantly improved the detection rate of CHD compared with univariate regression models. The four parameters demonstrated statistical significance in different CHD subtypes, especially in severe forms of CHD, confirming their value as effective parameters for early CHD screening in fetuses. Conclusion: CAx, CTR, VSA, and CSI were identified as effective parameters for the early diagnosis of CHD in fetuses during the first trimester. This research has, for the first time, established normal reference value ranges for the four parameters in early pregnancy and developed a multiparameter joint prediction model. The findings provide quantifiable indicators for CHD screening and further enhance the accuracy of CHD prediction in early pregnancy.