Introduction: Building a reference for fetal heart measurements
Understanding normal fetal cardiac development is essential for early detection of subtle heart abnormalities. A recent cross‑sectional study in the north‑eastern Egyptian population (Qalyubiyya Governorate) fills a crucial gap by establishing gestational‑age (GA) specific reference ranges and nomograms for 23 fetal echocardiographic measurements in low‑risk singleton pregnancies.
By documenting how cardiac structures grow from mid‑second trimester to late third trimester, clinicians gain a reliable baseline to identify remodeling patterns that may signal congenital or functional issues. The study analyzed 900 healthy pregnant women and used two‑dimensional echocardiography to measure everything from ventricular dimensions to great vessel diameters and the foramen ovale.
Methods and scope
The cohort included singleton pregnancies with GA ranging from 14+6 to 36+6 weeks. Measurements encompassed: cardiac circumference (CC), thoracic circumference (TC), inner diameters of both atria and ventricles, foramen ovale (FO) diameter, myocardial wall and interventricular septal thickness, atrioventricular (AV) valve rings, arterial roots, great vessels, and the transverse ductus arteriosus. Additional parameters included cardiac axis and thoraco‑cardiac relationships.
All scans followed ISUOG and American Society of Echocardiography guidelines, and images were acquired with high‑quality transducers. Age dating combined menstrual history with early fetal biometry. Data were analyzed in R and SPSS to derive centiles and regression equations, enabling construction of centile graphs and nomograms.
Key findings: growth patterns and model fit
All fetal cardiac dimensions increased with gestational age and showed non‑normal distributions. The team tested multiple regression models and found quadratic regression often provided the best fit for most measurements, though linear, cubic, and exponential models were also explored. The resulting nomograms translate GA into predicted cardiac dimensions and centiles (10th, 25th, 50th, 75th, 90th).
Notably, the study documented consistent propotional growth across chambers and major vessels, reflected in several stable ratios. For example, the right atrium to left atrium (RA/LA) ratio hovered around 1.0–1.1, while the right ventricle to left ventricle (RV/LV) ratio approached 1.1 as gestation advanced. The FO/AA (foramen ovale to aortic root) ratio remained near unity, indicating a balanced development of inlet and outlet structures on the left heart side.
Why these nomograms matter for prenatal care
These GA‑specific reference ranges and nomograms serve as a practical tool for clinicians to detect atypical cardiac remodeling early. In a population where data on normal fetal heart dimensions were previously scarce, establishing local nomograms improves diagnostic accuracy and the ability to compare a fetus against population‑matched norms rather than extrapolating from non‑local datasets.
The study’s emphasis on a low‑risk, well‑defined cohort provides clinicians with confidence in using these charts during routine anomaly scans, Doppler assessments, and follow‑up visits. In addition to static measurements, the researchers highlighted the value of centile graphs and regression curves in tracking individual growth trajectories over gestation.
Clinical implications and future directions
With 23 measured dimensions spanning chambers, valves, and great vessels, the nomograms pave the way for nuanced screening of fetal cardiac function and anatomy. They also offer a baseline to investigate how adverse environments or maternal factors may influence early cardiac remodeling. The authors note that further work could include multicenter validation, integration with Doppler flow metrics, and longitudinal studies to assess postnatal outcomes relative to prenatal dimensions.
Conclusion
The first trial of GA‑specific nomograms for fetal cardiac measurements in the north‑eastern Egyptian population delivers essential baseline data for early detection of remodeling patterns. By providing reference ranges, centile graphs, and robust regression equations for 23 cardiac measurements, this study supports improved prenatal care and outcomes in this regional cohort.
