Umbilical Vein Doppler Evaluation in Small for Gestational Age Fetuses With Normal Umbilical Artery Doppler Findings: A Prospective Cohort Study Publisher



M Parsaei MOHAMMADAMIN ; Z Zamanpour ZEYNAB ; Z Ghasemipour Afshar ZAHRA ; M Noorafrooz MOHAMMADAMIN ; M Dashtkoohi MOHADESE ; M Taghva Nakhjiri MOBINA ; Zh Madani Zahra HAMIDI ; M Aliasgharpoor MARYAM ; Zy Panahi Zahra YAZDAN ; F Ghotbizadeh Vahdani FAHIMEH
Source: Journal of Ultrasound in Medicine Published:2025

Abstract

Objectives: The umbilical vein (UV) plays a crucial role in fetal oxygenation, and its dysfunction may contribute to adverse outcomes in small-for-gestational-age (SGA) fetuses. We hypothesized that UV Doppler assessment could enhance risk stratification and guide delivery timing. This study compared UV hemodynamics between SGA and appropriately-for-gestational-age (AGA) fetuses to evaluate their predictive value for low birth weight. Methods: In this prospective cohort study (Tehran, Iran; July–December 2024), we included singleton pregnancies >32 weeks. SGA was defined as estimated fetal weight (EFW) or abdominal circumference (AC) <10th percentile, excluding fetal growth restriction (EFW/AC <3rd percentile or additional Doppler abnormalities). UV flow (UVF), EFW-normalized UVF (nUVF), and UV diameters (intra-abdominal and free-loop) were compared between SGA and AGA cohorts. Predictive performance for low birth weight (<2500 g) was assessed via receiver operating characteristic (ROC) analysis. Results: Among 322 pregnancies (78 SGA, 24.2%), SGA fetuses exhibited significantly lower UVF (172.1 versus 216.3 mL/min; P <.001), nUVF (76.4 versus 81.4 mL/minute/kg; P =.048), and narrower UV diameters (both P <.001). After adjustment, differences persisted except for nUVF. UVF and UV diameters moderately predicted low birth weight (areas under the ROC curve [AUCs] >.70), with free-loop diameter showing the highest discrimination (AUC =.798, 95% confidence interval: 0.687–0.909). Conclusions: SGA fetuses with normal umbilical artery Doppler demonstrate significant UV hemodynamic changes. UV Doppler, particularly free-loop diameter, may help identify high-risk pregnancies, aiding delivery planning. These findings support further exploration of UV assessment in SGA management protocols. © 2025 Elsevier B.V., All rights reserved.