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Uterine artery impedance at very early clinical pregnancy
Author(s) -
GuedesMartins Luís,
Saraiva Joaquim,
Gaio Rita,
Macedo Filipe,
Almeida Henrique
Publication year - 2014
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.4325
Subject(s) - notching , uterine artery , percentile , medicine , gestation , gestational age , confidence interval , pregnancy , obstetrics , pulsatility index , gynecology , fetus , mathematics , statistics , materials science , biology , metallurgy , genetics
ABSTRACT Objective The aim of the study was to construct gestational age‐based reference ranges for the uterine artery (UtA) mean pulsatility (PI) and resistance (RI) indices from 6 to 10 weeks of pregnancy. Method A prospective, cross‐sectional, observational study was carried out in 312 singleton pregnancies with gestational age ranging from 6 to 10 weeks. UtAs were examined transvaginally by color and pulsed Doppler imaging, and the mean of the right and left values of PI and RI, as well as the presence or absence of a bilateral protodiastolic notch, was recorded. UtA‐PI and UtA‐RI reference percentiles were derived through time‐conditional quantile regression. Results The authors derived the 10th, 50th, and 90th reference percentile curves and correspondent 95% confidence intervals, for the evolution of the UtA mean PI and RI from week 6 to week 10 of gestation. The prevalence of bilateral notching absence was 8.1% (6/74) at 6 weeks and 28.8% (15/52) at 10 weeks. Conclusion The authors present evidence of progressive reduction of uterine vascular impedance in a very early stage of pregnancy and provide new, averaged UtA‐PI and UtA‐RI charts between 6 and 10 weeks of gestation. © 2014 John Wiley & Sons, Ltd.