Reference ranges and Z-scores for fetal cardiac measurements from two-dimensional echocardiography in Asian population

Abstract

Currently available fetal echocardiographic reference values are derived mainly from North American and European population studies, and there is a lack of reference z-score for fetal echocardiographic measurement in Asian populations. The aim of this study was to establish normal ranges of echocardiographic measurements and z-scores in healthy Asian fetuses. A total of 575 healthy pregnant Taiwanese with an estimated gestational age from 14 to 38 weeks were enrolled voluntarily for this observational study. Standard two-dimensional echocardiography was performed to obtain measurements of the cardiac chambers and great arteries of the developing fetuses. In contrast to past studies, our sample was more evenly distributed for estimated gestational age (p<0.001). We present percentile graphs for 13 fetal echocardiographic measurements from the knowledge of estimated gestational age, biparietal distance, head circumference, abdominal circumference, and femur length. Most cardiac structures and developmental markers had linear models as the bestfitting, except for transverse aortic isthmus by estimated gestational age and transverse ductus arteriosus by femur length. Our findings indicate that estimated gestational age was generally the best model for fetal heart development, while head circumferences could be used as an optimal developmental marker to predict left atrium, right atrium, right ventricle, pulmonary annulus, and ductus arteriosus. Lastly, we developed nomograms for each of the 13 fetal heart measurements by each developmental markers. This is the first study providing echocardiographic reference ranges and nomograms for Asian fetuses. Computing z-scores from nomograms helps in standardizing comparisons and adds additional prognostic information to the diagnosis of congenital heart disease.

Assessment of the Size and Shape of the 4-Chamber View and the Right and Left Ventricles Using Fetal Speckle Tracking in Normal Fetuses at 17–24 Gestational Weeks

“…The shaded area represents ±1 z -score value. The lines indicate the z -score values computed for Gembruch et al [21], Li et al [22], Lussier et al [19], Garcia-Otero et al [2], and DeVore et al [28].…”

“…Speckle tracking software also may be not available on all ultrasound machines [28]. Furthermore, due to all measurements in this study performed by only 1 operator, the interobserver reproducibility could not be evaluated, and there might be potential intraobserver bias despite an unlikely event in an experienced hand [5,7,8,16,17,19,21,[28][29][30][31][32]. To demonstrate our measurements in clinical use, further research is warranted to evaluate fetal cardiac size and shape in details for diagnosis, serial monitoring, predicting postnatal outcome, and possible treatment in each fetal cardiac pathology.…”

“…Since the fetal heart does not have the same growth rate as the fetal body [28], we identified the best-fitted regression equations to calculate both the means and SDs as a function of 6 independent variables. Prior studies have reported that the end-diastolic length, width, area, and circumference of the 4CV and both ventricles were strongly correlated with all the independent variables [2, 19, 22, 23, 26]. As for which of the independent variables is the best model, the GA may not be a perfect one to use since the fetal heart size may vary based upon the underlying fetal conditions, especially in fetuses with abnormal growth or an unreliable menstrual age [22, 25, 28].…”

“…Standardized reference ranges of fetal cardiac size and function are essential for the detection of cardiac abnormalities and to generate prognostic information for prenatal counseling and postnatal planning treatment [19]. Previous studies have reported the nomograms of fetal cardiac size ranging from the first trimester to the end of the pregnancy using M-mode and 2-dimensional echocardiography in which the area, length, and size of the chambers have been measured [2,4,[19][20][21][22][23][24][25][26][27]. However, there are no normative data using speckle tracking analysis in fetuses between 17 and 20 weeks of gestation.…”

“…Racial variability may result in discrepancy in fetal cardiac size throughout the gestation period [20]. Few studies have constructed reference values of fetal cardiac size and shape in the Asian population [19, 20, 22, 27]. Therefore, the aim of the current study was to establish normal reference values obtained by measuring the shape, area, length, and width of the 4CV using the point-to-point trace of the epicardium and the shape, area, length, and width of the right and left ventricles using speckle tracking analysis between 17 and 24 weeks of gestation in Thai fetuses.…”