Overview
Researchers conducted the first trial to develop normal reference ranges and nomograms for fetal cardiac measurements in the northeastern Egyptian population (Qalyubiyya Governorate). The study focused on pregnancies between 14+6 and 36+6 weeks of gestation, using two-dimensional echocardiography to assess 23 cardiac dimensions in 900 low-risk singleton pregnancies. The aim was to define growth patterns of cardiac structures and provide clinically useful tools for detecting subtle congenital anomalies early in pregnancy.
Why GA-Specific Fetal Cardiac References Matter
Accurate fetal cardiac measurements are essential for tracking cardiac remodeling and understanding how the fetal heart adapts to varying intrauterine environments. Establishing gestational-age (GA) specific references helps clinicians interpret measurements within the right developmental context, reducing false positives for congenital heart disease and enabling timely intervention planning.
Methods in Brief
The cross-sectional study enrolled 900 healthy pregnant women with singleton pregnancies who underwent routine antenatal scans at Benha University Hospital. Measurements included:
- Cardiac circumference (CC) and thoracic circumference (TC)
- Inner diameters of the atria and ventricles
- Foramen ovale diameter, myocardial and interventricular septal thickness
- Atrioventricular valve ring diameters, arterial root diameters, great vessel diameters
- Transverse ductus arteriosus diameter, among others
2D echocardiography followed ISUOG and ASE guidelines, with measurements taken end-diastole or end-systole as appropriate and reported in millimeters. Measurements were captured during a comprehensive four-chamber view and supplemental planes, ensuring clear visualization and consistent technique.
Statistical Approach and Key Findings
All fetal cardiac dimensions increased with gestational age and were non-normally distributed. Regression analyses (linear, cubic, quadratic, and exponential) were applied to model relationships with GA. Although several models fit well, the quadratic regression often provided the best fit for most dimensions. Key outputs included:
- GA-specific reference ranges and centile charts (10th, 25th, 50th, 75th, 90th)
- Nomograms translating GA to expected measurements
- Observation of stable RA/LA and FO/AO relationships across gestation
The study demonstrated that 23 fetal echocardiographic measurements could be robustly described across the 14+6 to 36+6 weeks window, with quadratic growth patterns reflecting accelerating development in later pregnancy.
Clinical Implications
Clinicians can use these nomograms and reference ranges to assess fetal cardiac size, chamber dimensions, and vessel diameters against GA-based expectations. The work supports earlier recognition of atypical remodeling, enabling enhanced prenatal counseling, surveillance, and potential perinatal planning in populations with similar demographics.
Context within Global Research
Our findings align with prior international work showing non-normal distributions and quadratic growth of fetal cardiac parameters. The study adds valuable population-specific data for Egypt and contributes to the broader effort to create accessible nomograms that improve universal prenatal care.
Study Limitations and Future Directions
Limitations include a cross-sectional design and focus on a low-risk cohort. Future research could expand to diverse Egyptian regions, include multi-center longitudinal follow-up, and assess postnatal outcomes to further validate the predictive value of these nomograms.
Conclusion
This pioneering study provides GA-specific reference ranges, regression equations, centile graphs, and nomograms for 23 fetal echocardiographic measurements in the northeastern Egyptian population. The work offers essential baselines for early detection of fetal cardiac remodeling and supports enhanced prenatal care in Egypt and similar settings.
