Revision as of 11:00, 16 December 2025

Abstract

The umbilical artery (UA) plays a vital role in the exchange of substances between the mother and fetus through fetal circulation. In silico computational fluid dynamics (CFD) has emerged as an effective tool for simulating and analyzing UA blood flow, especially when combined with clinical Doppler ultrasound data. However, most existing studies have applied CFD to investigate UA hemodynamics only at isolated stages of gestation. In reality, UA hemodynamics undergoes continuous changes throughout fetal morphogenesis and physiological development during the entire gestational period. To address this gap, the present study employs CFD to investigate the evolution of UA hemodynamics across eight consecutive gestational age groups: 19, 23, 25, 27, 30, 33, 36, and 39 weeks. The simulations are based on Doppler ultrasound data acquired from clinical examinations of fetuses. The results demonstrate that UA blood flow velocity, secondary helical flow intensity, pressure drop, and wall shear stress generally increase with advancing gestational age. Furthermore, statistical analysis of clinical data across different gestational weeks reveals that the ratio of the Dean number to the Reynolds number (i.e., square root of the dimensionless curvature) remains basically stable during fetal development, with a value of 0.57 ± 0.06. This finding offers new insight into the scaling behavior of UA flow dynamics and may serve as a useful reference for clinical assessments. Overall, this CFD-based investigation provides a comprehensive characterization of UA hemodynamic development and may assist clinicians in gaining a deeper understanding of fetal circulatory adaptation throughout gestation.

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