# 3D Umbilical Venous Blood Flow - A New Paradigm for Improving the Assessment of Fetal Growth Restriction.

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 2020 · $657,144

## Abstract

Significance: Fetal growth restriction (FGR) is an independent predictor of infant and lifelong morbidity and
mortality of non-anomalous fetuses. However, fetal biometry alone does not reliably distinguish between small
fetuses at risk for poor outcomes from those that are constitutionally small. Considerable efforts have been
directed toward developing more robust methods for the detection and monitoring of small fetuses at risk for
adverse outcomes. Conventional efforts for measuring umbilical venous blood flow (UVBF), using conventional
2D vessel diameter measurements with Doppler velocimetry, have been challenging due to technical factors that
make it impractical for routine clinical practice. We will address this problem by using 3D sonography to measure
umbilical venous blood flow (3D UVBF). This approach combines color flow Doppler ultrasound with a 2D array
transducer to quantify volume flow in a manner that does not require a priori knowledge of small vessel diameter,
Doppler insonation angle, flow velocity profile, or vessel geometry. Hypotheses: 1) 3D UVBF is an accurate and
reproducible sonographic parameter for measuring umbilical venous flow throughout gestation; 2) Reference
standards for 3D UVBF will be readily generated that provide a necessary framework for prospective analyses;
and 3) A predictable and progressive circulatory deterioration pattern, based on 3D UVBF, occurs significantly
more frequently among small fetuses (EFW < 10th%) with adverse outcomes when compared to other small
fetuses without complications. Preliminary Data: We have shown that the 3D UVBF % error, relative to average
measured arterial and venous flow, was ≤ 10% for 8 of 9 measurements in exteriorized fetuses of pregnant ewes.
Lower than expected 3D UVBF values were found in 2 of 7 fetuses from human pregnancies that later developed
FGR or preeclampsia (Pinter S, et al. J Ultrasound Med 37:1633-1640, 2018). In further reproducibility studies,
the 3D UVBF intra-subject and intra-measurement relative standard errors (RSE) were 12.1 ± 5.9 and 5.6 ± 1.9
% (mean ± SD), respectively (n=35). Specific Aims: We propose to validate 3D UVBF, develop 3D UVBF
reference standards, and provide detailed observations of circulatory changes in small fetuses with EFW < 10th%.
In Specific Aim 1, in-vitro flow phantom experiments and reproducibility studies in pregnant women will examine
the accuracy and reproducibility of 3D UVBF. In Specific Aim 2, serial ultrasound scans will develop prescriptive
3D UVBF reference standards in 400 non-anomalous fetuses with normal growth outcomes. In Specific Aim 3,
circulatory patterns of multi-vessel Doppler velocimetry and 3D UVBF changes will be determined in a
prospective cohort of 1100 small fetuses. The added value of 3D UVBF and related Doppler circulatory patterns
in identifying small fetuses with adverse perinatal outcomes or neonatal morbidities will be examined. Successful
execution of our Aims should establish 3D UVBF as a r...

## Key facts

- **NIH application ID:** 9984890
- **Project number:** 5R01HD097756-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** JEFFREY B FOWLKES
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $657,144
- **Award type:** 5
- **Project period:** 2019-08-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9984890

## Citation

> US National Institutes of Health, RePORTER application 9984890, 3D Umbilical Venous Blood Flow - A New Paradigm for Improving the Assessment of Fetal Growth Restriction. (5R01HD097756-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9984890. Licensed CC0.

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