How useful is uterine artery Doppler flow velocimetry in the prediction ofpre-eclampsia, intrauterine growth retardation and perinatal death? An overview

Objective To evaluate the clinical usefulness of Doppler analysis of the ut erine artery velocity waveform in the prediction of pre-eclampsia and its a ssociated complications of intrauterine growth retardation and perinatal de ath. Design Quantitative systematic review of observational diagnostic studies u sing online searching of the MEDLINE database coupled with scanning of the bibliographies of primary and review articles including known unpublished s tudies. Material Twenty-seven studies involving 12,994 subjects stratified into pop ulation subgroups at low and high risk of developing pre-eclampsia and its complications. Outcome measures The outcome measures studied were: 1. the development of p re-eclampsia; 2, intrauterine growth retardation; and 3. perinatal death. T he main meta-analyses were the flow velocity waveform ratio +/- diastolic n otch derived by transabdominal Doppler ultrasound as the:measurement parame ter The analyses were conducted using likelihood ratio as a measure of diag nostic accuracy. A likelihood ratio of 1 indicates that the test has no pre dictive value for the outcome. prediction for the outcome event is consider ed conclusive with Likelihood ratios of > 10 or < 0.1 for a positive and ne gative test result, respectively. Moderate prediction can be achieved with likelihood ratios of 5-10 and 0.1-0.2 whereas likelihood ratios values of 1 -5 and 0.2-1 would generate only minimal prediction. Results In the low risk population a positive test result, predicted pre-ec lampsia with a pooled likelihood ratio of 6.4 (95% CI 5.7-7.1), while a neg ative test result had a pooled likelihood ratio of 0.7 (95% CI 0.6-0.8). Fo r intrauterine growth retardation the pooled Likelihood ratio was 3.6 (95% CII 3.2-4.0) for a positive test result and 0.8 (95% CI 0.8-0.9) for a nega tive test result. Using perinatal death as outcome measure, the pooled like lihood ratio was 1.8 (95% CI 1.2-2.9) for a positive test result and 0.9 (9 5% CI 0.8-1.1) for a negative test result. In the high risk population a po sitive test: result predicted pre-eclampsia with a pooled Likelihood ratio of 2.8 (95% CI 2.3-3.4), while a negative test had a likelihood ratio of 0. 8 (95% CI 0.7-0.9). For intrauterine growth retardation the pooled likeliho od ratio was 2.7 (95% CI 2.1-3.4) for a positive test result and 0.7 (95% C T 0.6-0.9) for a negative result. For perinatal death the pooled likelihood ratio was 4.0 (95% CI 2.4-6.6) for a positive test result and 0.6 (95% CI 0.4-0.9) for a negative result. Conclusion Uterine artery Doppler flow velocity has limited diagnostic accu racy in predicting preeclampsia, intrauterine growth retardation and perina tal death.