Journal Club: First-trimester uterine artery Doppler and adverse pregnancy outcome: a meta-analysis involving 55 974 women
Authors: L. VELAUTHAR, M. N. PLANA, M. KALIDINDI, J. ZAMORA, B. THILAGANATHAN,
S. E. ILLANES, K. S. KHAN, J. AQUILINA and S. THANGARATINAM
Published in: Ultrasound Obstet Gynecol 2014; 43: 500–507
Objectives: To determine the accuracy with which uterine artery Doppler in the first trimester of pregnancy predicts pre-eclampsia and fetal growth restriction, particularly early-onset disease.
Methods: We searched MEDLINE (1951–2012), EMBASE (1980–2012) and the Cochrane Library (2012) for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of first-trimester uterine artery Doppler to predict adverse pregnancy outcome and performed data extraction to construct 2×2 tables. We synthesized sensitivity and specificity for various Doppler indices using a bivariate random-effects model.
Results: From 1866 citations, we identified 18 studies (55 974 women). The sensitivity and specificity of abnormal uterine artery flow velocity waveform (FVW) in the prediction of early-onset pre-eclampsia were 47.8% (95% CI: 39.0–56.8) and 92.1% (95% CI: 88.6–94.6), and in the prediction of early-onset fetal growth restriction were 39.2% (95% CI: 26.3–53.8) and 93.1% (95% CI: 90.6–95.0), respectively. The sensitivities for predicting any pre-eclampsia and fetal growth restriction were 26.4% (95% CI: 22.5–30.8) and 15.4% (95% CI: 12.4–18.9), respectively, and the specificities were 93.4% (95% CI: 90.4–95.5%) and 93.3% (95% CI: 90.9–95.1), respectively. The number needed to treat (NNT) with aspirin to prevent one case of early-onset pre-eclampsia fell from 1000 to 173 and from 2500 to 421 for background risks varying between 1% and 0.4%, respectively.
Conclusions First-trimester uterine artery Doppler is a useful tool for predicting early-onset pre-eclampsia, as well as other adverse pregnancy outcomes. Based on the NNT, abnormal uterine artery Doppler in low-risk women achieves a sufficiently high performance to justify aspirin prophylaxis in those who test positive.