International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project

BackgroundReference values for umbilical artery Doppler indices are used clinically to assess fetal well-being. However, many studies that have produced reference charts have important methodologic limitations, and these result in significant heterogeneity of reported reference ranges.ObjectivesTo produce international gestational age-specific centiles for umbilical artery Doppler indices based on longitudinal data and the same rigorous...