Umbilical artery Doppler velocimetry in unselected and low risk pregnancies: A review of randomised controlled trials

Objective Meta-analysis of data from controlled trials performed in populations at high risk have shown that umbilical artery Doppler velocimetry (umbilical Doppler) can reduce perinatal mortality. The individual published trials among unselected or low risk populations have found no beneficial effect. Our objective was to evaluate the effect of routine use of the umbilical Doppler in unselected or low risk pregnancies by reviewing all published and unpublished randomised controlled trials. Study design Systematically reviewing published and unpublished trials, we selected trials for the overview only if they were completed randomised trials of umbilical Doppler in unselected or low risk pregnancies. Of the seven trials examined, three were not included in the meta-analysis because of methodological problems or because they did not meet the inclusion criteria. We therefore included four trials: two in unselected and two in low risk populations. These four groups were comparable in their degree of maternal and perinatal risk. Using the Mantel-Haenzel statistical method and pooling the data, we considered 11,375 women in the meta-analysis. Results Systematic use of the Doppler umbilical artery velocimetry had no statistically significant effect on perinatal deaths in unselected populations (odds ratio [OR] 1.28; 95% confidence interval [CI] 0.61-2.67), low risk populations (OR 0.51; 95% CI 0.20-1.29) or overall for the four trials (OR 0.90; 95% CI 0.50-1.60); nor was there any significant effect on stillbirths (global OR 0.94; 95% CI 0.42-1.98). However, the number of' participants remain insufficient and further information is required to arrive at a definite conclusion on the absence of effect. The meta-analysis showed no significant difference between the Doppler groups and the control groups for antenatal hospitalisation, obstetric outcome or perinatal morbidity. Conclusion Based on the results of the published trials, routine use of the umbilical Doppler cannot be recommended.