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

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of the MEDLINE database coupled with scanning of the bibliographies of primary and review articles including known unpublished studies.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 x 1 for a positive and negative test result, respectively. Moderate prediction can be achieved with likelihood ratios of 5-10 and 0 x 1-0 x 2 whereas likelihood ratios values of 1-5 and 0 x 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 x 4 (95% CI 5 x 7-7 x 1), while a negative test result had a pooled likelihood ratio of 0 x 7 (95% CI 0 x 6-0 x 8). For intrauterine growth retardation the pooled likelihood ratio was 3 x 6 (95% CI 3 x 2-4 x 0) for a positive test result and 0 x 8 (95% CI 0 x 8-0 x 9) for a negative test result. Using perinatal death as outcome measure, the pooled likelihood ratio was 1 x 8 (95% CI 1 x 2-2 x 9) for a positive test result and 0 x 9 (95% CI 0 x 8-1 x 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 x 8 (95% CI 2 x 3-3 x 4), while a negative test had a likelihood ratio of 0 x 8 (95% CI 0 x 7-0 x 9). For intrauterine growth retardation the pooled likelihood ratio was 2 x 7 (95% CI 2 x 1-3 x 4) for a positive test result and 0 x 7 (95% CI 0 x 6-0 x 9) for a negative result. For perinatal death the pooled likelihood ratio was 4 x 0 (95% CI 2 x 4-6 x 6) for a positive test result and 0 x 6 (95% CI 0 x 4-0 x 9) for a negative result.

CONCLUSION: Uterine artery Doppler flow velocity has limited diagnostic accuracy in predicting pre-eclampsia, intrauterine growth retardation and perinatal death.