Intraobserver and interobserver reproducibility of third trimester uterine artery pulsatility index

Objectives: The primary aim of the study was to investigate intraobserver and interobserver reproducibility of uterine artery (UtA) pulsatility index (PI) in the third trimester of pregnancy. The secondary aim of the study was to examine whether high maternal body mass index (BMI) or gestational age (GA) influence the reliability of this measurement. Methods: Singleton pregnancies in women with known BMI were recruited between 30+0 and 40+0 weeks. UtA PI Doppler measurements were performed prospectively, independently, and blindly by 2 Fetal Medicine Foundation–accredited operators. Intraobserver and interobserver reproducibility was assessed by concordance correlation coefficient (CCC) and intraclass correlation coefficient (ICC); Bland-Altman plots were built and limits of agreement (LoA) were calculated. The analysis was performed for both raw numbers and percentiles. To estimate the intraoperator and interoperator agreement in defining normal and pathological measurements, the assessments were divided in 2 categories—UtA PI