Evaluating the predictive value of uterine artery Doppler ultrasound in a high-risk population.

Introduction: In the United Kingdom, uterine artery Doppler ultrasound, specifically measurement of the pulsatility index, is recommended in the second trimester of pregnancies at risk of developing conditions like pre-eclampsia and fetal growth restriction, to facilitate timely monitoring and intervention. The aim of this study was to evaluate the effectiveness of uterine artery Doppler in detecting pregnancies at risk for adverse outcomes by analysing a cohort of high-risk pregnancies.

Methods: A total of 218 pregnancies were retrospectively selected post-delivery, having been identified prior to anomaly scanning as at high risk for adverse outcomes. They had bilateral uterine artery Doppler between 18 and 24 weeks of gestation as part of normal care. Mean uterine artery pulsatility index above the 95th percentile was considered abnormal. Subjects received close monitoring in the third trimester, including 2-3 weekly growth ultrasounds with umbilical artery Doppler, and regular blood pressure checks. Sensitivity, specificity, positive predictive value and negative predictive value of uterine artery Doppler were calculated to assess its predictive accuracy for pre-eclampsia and low birthweight.

Results: Sensitivity of uterine artery Doppler > 95th percentile was 20% for pre-eclampsia (positive predictive value: 14%) and 46% for birthweight < 3rd centile (positive predictive value: 30%). Specificity was 80% for pre-eclampsia (negative predictive value: 86%) and 84% for birthweight < 3rd centile (negative predictive value: 91%).

Conclusion: Uterine artery Doppler pulsatility index alone has limited sensitivity for predicting pre-eclampsia, and small for gestational age births in a high-risk population. These findings underscore the need for multimodal approaches, incorporating other biomarkers and clinical risk factors.