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A new non‐invasive method for measuring uterine vascular resistance and its relationship to uterine artery Doppler indices: a longitudinal study
Author(s) -
Flo K.,
Wilsgaard T.,
Acharya G.
Publication year - 2011
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.8907
Subject(s) - medicine , uterine artery , pulsatility index , doppler effect , vascular resistance , gestation , diastole , ultrasonography , laser doppler velocimetry , blood flow , cardiology , hemodynamics , nuclear medicine , blood pressure , pregnancy , fetus , surgery , physics , genetics , astronomy , biology
Objectives To describe a new method for measuring uterine vascular resistance ( R uta ), establish longitudinal reference ranges and explore the relationship between uterine artery (UtA) Doppler indices and R uta . Methods This was a longitudinal study of 53 low‐risk pregnancies. Doppler ultrasonography was used to measure UtA velocities, and the pulsatility index (PI), resistance index (RI) and systolic/diastolic velocity (S/D) ratio were calculated. R uta was calculated as a ratio between maternal mean arterial pressure and UtA time‐averaged maximum velocity. Results At 22 + 0 to 39 + 6 weeks of gestation, the mean R uta decreased from 1628 to 1180 dyne.s/cm 3 ( P < 0.0001). UtA velocities increased ( P < 0.0001), whereas the PI (0.79–0.56), RI (0.51–0.40) and S/D ratio (2.0–1.7) decreased ( P < 0.0001). R uta and the UtA Doppler indices were positively associated ( P = 0.003–0.001). Conclusion We describe a non‐invasive method for measuring R uta and provide reference ranges for serial evaluation of UtA velocities, Doppler indices and R uta . Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.