Objective To evaluate the clinical usefulness of Doppler analysis of the uterine artery velocity waveform in the prediction of pre-eclampsia and its associated complications of intrauterine growth retardation and perinatal death.
Design Quantitative systematic review of observational diagnostic studies using online searching of the MEDLINE database coupled with scanning of the bibliographies of primary and review articles including known unpublished studies.
Material Twenty-seven studies involving 12,994 subjects stratified into population subgroups at low and high risk of developing pre-eclampsia and its complications.
Outcome measures The outcome measures studied were: 1. the development of pre-eclampsia; 2. intrauterine growth retardation; and 3. perinatal death. The main meta-analyses were the flow velocity waveform ratio ± diastolic notch derived by transabdominal Doppler ultrasound as the measurement parameter. The analyses were conducted using likelihood ratio as a measure of diagnostic accuracy. A likelihood ratio of 1 indicates that the test has no predictive value for the outcome. Prediction for the outcome event is considered conclusive with likelihood ratios of > 10 or < 0.1 for a positive and negative 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-eclampsia with a pooled likelihood ratio of 6.4 (95% CI 5.7–7.1), while a negative test result had a pooled likelihood ratio of 0.7 (95% CI 0.6–0.8). For intrauterine growth retardation the pooled likelihood ratio was 3.6 (95% CI 3.2–4.0) for a positive test result and 0.8 (95% CI 0.8–0.9) for a negative test result. Using perinatal death as outcome measure, the pooled likelihood ratio was 1.8 (95% CI 1.2–2.9) for a positive test result and 0.9 (95% CI 0.8–1.1) for a negative test result. In the high risk population a positive 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 likelihood ratio was 2.7 (95% CI 2.1–3.4) for a positive test result and 0.7 (95% CI 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 accuracy in predicting preeclampsia, intrauterine growth retardation and perinatal death.