Reference ranges for Doppler indices of umbilical and fetal middle cerebral arteries and cerebroplacental ratio: systematic review

Abstract

There is considerable methodological heterogeneity in studies reporting reference ranges for Doppler indices of UA, MCA and CPR, and the resulting references have important implications for clinical practice. There is a need for the standardization of methodologies for Doppler velocimetry and for the development of reference standards, which can be correctly interpreted and applied in clinical practice. We propose a set of recommendations for this purpose. This article is protected by copyright. All rights reserved.

Ultrasound angiology reference standards of fetal cerebroplacental flow in normal Egyptian gestation: statistical analysis of one thousand observations

“…Three quarters of the published references were performed by one sonographer. Multisonographer observations increase external efficacy and data reliability [53]. The current study was performed by 3 radiologists with long term experience 5-25 years in feto-maternal Doppler ultrasonography (Fig.…”

“…In great numbers of observations, each case was examined at least three times and the study was based on a population that had no pregnancy risk nor complications, and surely, the current study reference ranges are reliable and could be applicable in the general population. Both the median and variance ought to be displayed as a function of gestational age in a way that accounts for the expanding variability with gestation and affords smooth centile curves; goodness of fit testing ought to illustrate that these curves depict precisely the structure of the raw information [53]. The present study created scattered diagram curves of gestational age individual measurements and calculated CPR reference ranges for MCA/UA PSV, S/D ratio, RI, and PI in 1284 observations with 1st-99th percentiles, and 50th percentiles clearly demonstrate our tabulated raw data.…”

Maternal and perinatal factors associated with adverse perinatal outcomes at term and the development of a predictive model for identification of at–risk pregnancies.

“…Despite this, centiles for the MCA PI and UA PI as well as the CPR have often suffered from methodological flaws such as small sample size, suboptimal modelling and lack of reporting of model diagnostics or subsequent goodness-of-fit evaluation. According to Oros' systematic review on reference centiles for Doppler indices, Ebbings 2007 longitudinal reference ranges were methodologically the most robust that were published to date (93). However, when I applied Ebbings 10 th centile to the Mater obstetric cohort, I found that it was reflective of 20% of our population (i.e.…”

“…Also, whilst the multilevel modelling adjusts for the correlation within subjects, using the conditional reference intervals based on Royston's 1995 paper, further addresses the issue of bias and the possibility of unusual patterns arising from repeated measurements (89). (72) to be the highest scoring (93). Surprisingly there was no mention or reference to the methodology employed by the WHO for the Intergrowth-21 st project which conducted comprehensive research into appropriate methodology for anthropometry.…”

“…The final chapter investigating the ultrasound-based variables is dedicated to creating a new set of reference ranges for the UA PI, MCA PI and CPR. This was necessary as the existing reference ranges all suffered from poor methodology and in the case of the CPR, the ranges that have been described as using the most robust methodology we considered too high as 20% of our mothers had a CPR that was less than their 10 th centile (66,93).…”