EP38.02: Accuracy and reproducibility of the umbilical vein blood flow measurements: a systematic review

Umbilical vein blood flow (UV-Q) is a measure of placental blood supply to the fetus. Despite a potential clinical value, UV-Q assessment did not gained ground partly due to the concerns regarding the lack of accuracy and reproducibility in its measurement. The aim of the study was to perform a systematic review on the available UV-Q reference ranges in uncomplicated singleton pregnancies, in order to assess its accuracy and reproducibility. A systematic review of the literature reporting reference ranges for UV-Q in uncomplicated pregnancies were identified following the PRISMA. Selected articles were further grouped based on the UV sampling site (free-floating and intra-abdominal) and the formula used to compute UV-Q. The 50th percentile and/or the mean were derived from the formulae and/or from the reported percentiles. The initial research identified 587 publications. After removal of duplicates, reviews and all unsuitable for study type articles or population, the comparison was performed for 14 sets of data identified by the research strategy and 1 set from our local cohort (unpublished, presented in a separate abstract). We found a substantial heterogeneity among reported UV-Q central values, partially attributable to the sampling site (figure 1A-D) and type of formula used. When the comparison was made among curves obtained with the same methodology as ours, there was an impressive overlap (figure 1E-F). Our data suggest that, when adhering to standardised methodology, the assessment of the UV-Q is accurate and reproducible. This opens a prospective on possible clinical applications of this biophysical assessment in case of fetal growth restriction and/or stunted fetal growth. 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.