Full length article Inter- and intra-observer variability in fetal ductus venosus blood flow measurements in high-risk fetuses at 26–32 weeks Clara M. Bruin a, *, Wessel Ganzevoort a , Ewoud Schuit a,c , Nico A. Mensing van Charante a,b , Hans Wolf a a Department of Obstetrics and Gynaecology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands b Department of Gynaecology, Dijklander Ziekenhuis, Hoorn, the Netherlands c Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands A R T I C L E I N F O Article history: Received 28 May 2019 Received in revised form 12 September 2019 Accepted 17 October 2019 Available online xxx Keywords: Fetal growth restriction Ductus venosus Doppler ultrasonography Reproducibility of ductus venosus pulsatility index Correlation Variability A B S T R A C T Objectives: Early preterm fetal growth restriction is a significant contributor to perinatal morbidity and mortality. The ductus venosus pulsatility index for veins (DV PIV) is proposed as a monitoring tool because it appears to improve perinatal outcomes. The test characteristics and robustness of DV PIV have been inadequately described. The aim of this study was to investigate inter- and intra-observer variability of DV PIV. Study design: Nineteen women with a gestational age between 26 and 32 completed weeks were included in this study. Doppler sonographic fetal assessment was performed by two independent maternal-fetal medicine specialists. Each sonographer alternately performed three flow tracings for each participant, in the absence of the other sonographer (six tracings in total per patient). DV PIV was calculated automatically from stored tracings by a third researcher. Inter- and intra-observer variability of DV PIV and limits of agreement were assessed using the Bland–Altman method. Comparison of the distribution was performed with Kendall’s related samples test, and the intraclass correlation coefficient (ICC) was calculated. Results: In total, 114 DV measurements were taken from 19 participants with a median age of 31 years [interquartile range (IQR) 26–34 years] at a median gestational age of 28 weeks (IQR 27–29 weeks). The proportional limits of agreement for intra-observer variation were 0.48 to 0.48 and 0.39 to 0.62 for the two observers. ICCs were 0.66 [95% confidence interval (CI) 0.42–0.84] and 0.68 (95% CI 0.45–0.85). The proportional limits of agreement for inter-observer variation were 0.29 to 0.19 with an ICC of 0.89 (95% CI 0.73–0.96). Conclusion: Inter-observer variation was far less than intra-observer variation, probably due to mitigation of biological variation by averaging three measurements. DV PIV has acceptable test characteristics for use in a clinical setting when the average of at least three consecutive measurements is used. © 2019 Elsevier B.V. All rights reserved. Introduction Fetal growth restriction (FGR) is a significant contributor to perinatal morbidity and mortality. The incidence of adverse outcomes is high, particularly in preterm gestational ages. Timing of delivery is pivotal in early preterm FGR fetuses, and depends on anticipated risks of antenatal death and neonatal complications. When estimated risks of antenatal death exceed anticipated neonatal risks, delivery is indicated. Unfortunately, monitoring the fetal condition in diagnosed early preterm FGR is a challenge, thereby complicating the timing of delivery [1]. At present, cardiotocography (CTG) and Doppler ultrasound of the umbilical artery are at the cornerstone of clinical evaluation for timing of delivery [2,3]. Additional use of the ductus venosus pulsatility index for veins (DV PIV) to indicate delivery appears to improve perinatal outcomes. In a multicentre, prospective, observational study, adverse perinatal outcome could be predicted at 0–1 days before delivery by DV PIV of 3 standard deviations (SD) below the mean [odds ratio (OR) 11.3, 95% confidence interval (CI) 2.3–57], and at 2–7 days before delivery by DV PIV of 2 SD below the mean (OR 3.0, 95% CI 0.8–12) [4]. In a pragmatic randomized controlled trial with strict monitoring schedules, waiting for either abnormal CTG or DV changes (whichever came first) was * Corresponding author at: Amsterdam UMC, Department of Obstetrics and Gynaecology, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. E-mail address: c.m.bruin@amsterdamumc.nl (C.M. Bruin). https://doi.org/10.1016/j.ejogrb.2019.10.028 0301-2115/© 2019 Elsevier B.V. All rights reserved. European Journal of Obstetrics & Gynecology and Reproductive Biology 243 (2019) 67–71 Contents lists available at ScienceDirect European Journal of Obstetrics & Gynecology and Reproductive Biology journal homepage: www.elsevier.com/locate/ejogrb