Anatomical and proportional changes in the fetal thoracic cavity: implications for prenatal assessment.

BACKGROUND

Accurate characterization of fetal thoracic development is essential for improving prenatal assessment and early detection of structural abnormalities. The aim of this study was to evaluate the morphometric and proportional characteristics of the fetal thoracic cavity during mid and late gestational periods.

MATERIALS AND

METHODS

A total of 32 fetal specimens (16 mid gestation, 16 late-gestation) were included. Crown-rump length (CRL), transverse diameter (TD), anteroposterior diameter (AP), and thoracic circumference (TC) were measured and analyzed using descriptive statistics, between-group comparisons, correlation, and regression methods.

RESULTS

All parameters increased significantly from mid to late gestation (p < 0.001). The greatest relative growth was observed in TD (≈55%), indicating that transverse expansion represents the dominant pattern of thoracic development. Regression analysis demonstrated that in mid gestation, TC could be reliably predicted by TD alone, whereas in late gestation the inclusion of AP improved predictive accuracy, reflecting increasing structural complexity. Minimal clinically important difference (MCID) analysis confirmed that these changes were not only statistically significant but also clinically meaningful.

CONCLUSIONS

Fetal thoracic development follows stage-specific growth patterns with important clinical implications. The findings provide preliminary data that may support improved prenatal evaluation, the establishment of population-specific normative data, and enhanced prediction of fetal respiratory system maturity.