Uterine Artery Pulsatility Index Assessment at 11-13⁺⁶ Weeks' Gestation

Abstract

Introduction: First-trimester uterine artery pulsatility index (PI) measurements form part of an algorithm used to assess the risk of developing pre-eclampsia. The objective of this study was to construct a population-specific reference range for both the lower and mean maternal uterine artery PI at 11-13⁺⁶ weeks' gestation and to assess measurement agreement. Materials and Methods: Reference ranges for mean and lower PI measurements were developed using polynomial regression models following prospective collection of maternal uterine artery PI measurements at 11-13⁺⁶ weeks' gestation. Measurement agreement studies were performed by two experienced operators. Results: Measurements from 298 women were included in the primary study. Polynomial regression indicated no change over gestational age for the lower PI (mean 1.44). There was an inverse relationship between the average PI and gestational age (mean [0.8960 + (2.9771 × CRL^-1/2)]²). PI measurement agreement was good-strong (intraclass correlation (ICC) 0.50-0.79) between operators, and within-operator agreement was almost perfect (ICC 0.88-0.93). Conclusions: Reference ranges for both the average and lowest PI of the maternal uterine arteries were derived at 11-13⁺⁶ weeks' gestation. This will provide a basis for development of auditable standards for first-trimester uterine artery Doppler measurements. The PI measurements are reproducible and reliable.

Influence of Sampling Site on Uterine Artery Doppler Indices at 11-13⁺⁶ Weeks Gestation

“…The participants of this study were a cohort from a larger study recruited between May 2011 and April 2012 for the purposes of construction of a reference range for uterine artery PI at 11-13 +6 weeks [16]. Women attending the unit for first trimester aneuploidy screening were assessed for eligibility and provided with information about the study.…”

“…The inclusion and exclusion criteria for this study mirrored that of the larger study [16]. Women were eligible for inclusion if they had a singleton pregnancy with a CRL 45-84 mm on the day of the examination.…”

Role of Uterine Artery Doppler as a Predictor of Preeclampsia

“…This finding is consistent with other studies. (16,17,18) Our study demonstrated lower resistance and high velocity flow in normal pregnancies than increased resistance and pulsatility index with pregnancies associated with complications. This reflects there are changes in the uteroplacental circulation in very early stage in pregnancies, which are going to get complicated.…”

First Trimester Screening for Preeclampsia and Intrauterine Growth Restriction Using Uterine Artery Doppler and Maternal Serum Placental Growth Factor and Pregnancy Associated Plasma Protein- A

“…These physiological changes convert the spiral arteries from narrow muscular vessels to wide non-muscular channels independent of maternal vasomotor control. In placental dysfunction there is impaired trophoblastic invasion of spiral arteries and this impairment is most marked in PE and IUGR [6,7]. Indirect evidence of impaired placental perfusion in pregnancies destined to develop PE and IUGR has been provided by Doppler studies of the uterine arteries which showed increased PI during both the second and also in the first trimester of pregnancy [8].…”