VP37.02: Evaluating the physiological variability inherent in common maternal fetal pulsedwave Doppler parameters: a pilot study

Despite the ubiquitous use of pulsed-wave Doppler (PWD) derived-indices as a diagnostic tool in clinical practice, their degree of physiological variability has never been thoroughly evaluated. We aimed to report and evaluate the variability of maternal-fetal PWD derived-indices. 20 healthy, singleton pregnant women at 20–37 weeks' gestational age (GA) were recruited. 100 PWD waveforms were acquired for the left uterine (LtUt), right uterine (RtUt), umbilical (Umb), and middle cerebral arteries (MCA), using a GE VolusonTM E8 and 2D convex transducer (C4-8D) with machine settings set to ISUOG PWD guidelines. For each single waveform, systole/diastole ratio (S/D), resistance index (RI) and pulsatility index (PI) were automatically measured. Coefficient of variation (CoV) was calculated for each PWD index in each vessel and was linearly regressed versus GA (r). CoV results are shown in figure 1. Uterine artery PI and fetal vessel S/D and PI demonstrated CoV >10% over the time period, with all vessels showing greater variation in PI than RI, resulting in a lower correlation for PI (mean r = 0.12) than RI (mean r = 0.35). There is widespread variability in PWD indices, differing between vessels. Whilst PI includes ‘more’ waveform information, that comes with greater variability. Single or brief measurements of PWD waveforms may not be reflective of their mean state as there may be physiological variation of 10–15%. Supporting information can be found in the online version of this abstract Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.