Morphometric Study of Developing Human Fetal Trachea and Its Correlation with Fetal Growth Parameters: A Cross - Sectional Study

Background: The fetal trachea undergoes continuous growth and structural remodeling throughout gestation. Normative morphometric data are essential for understanding normal development, prenatal imaging, and early identification of congenital tracheobronchial anomalies. The aim is to evaluate the morphometric characteristics of the developing human fetal trachea across different gestational ages and correlate them with fetal growth parameters. Material and Methods: This cross-sectional observational study included 42 human fetuses of known gestational age, grouped into 13–21 weeks (n=18), 22–30 weeks (n=12), and 31–38 weeks (n=12). Fetal weight, crown-rump length, abdominal circumference, and head circumference were recorded. Tracheal measurements included total tracheal length, pre-bifurcation length, bifurcation length, proximal and distal transverse external diameters, total, right and left tracheobronchial angles, and the number of tracheal cartilages. Statistical analysis was performed using one-way ANOVA and Pearson's correlation coefficient. Results: Mean gestational age was 24.21 ± 7.53 weeks. Total tracheal length increased significantly from 14.99 ± 2.82 mm in the 13–21-week group to 30.56 ± 2.70 mm in the 31–38-week group. All tracheal morphometric parameters demonstrated significant age-related increases (p < 0.0001). Crown-rump length showed the strongest positive correlation with proximal transverse external diameter (r = 0.962), total tracheal length (r = 0.956), distal transverse external diameter (r = 0.956), and left tracheobronchial angle (r = 0.955), whereas the right tracheobronchial angle showed a strong negative correlation with fetal growth parameters. Conclusion: Human fetal tracheal dimensions increase progressively with gestational age and correlate strongly with fetal growth, particularly crown-rump length. These findings provide normative anatomical reference data that may facilitate prenatal evaluation and improve the recognition of congenital tracheobronchial abnormalities.

Keywords: fetal trachea; morphometry; gestational age; fetal growth; tracheobronchial angle.