A randomised controlled trial of Doppler ultrasound velocimetry of the umbilical artery in low risk pregnancies. Doppler French Study Group. Randomised comparison of routine versus highly selective use of Doppler ultrasound in low risk pregnancies.
To evaluate the effect on management and outcome of pregnancy of routine umbilical Doppler examination in low risk populations.
                Pragmatic randomised controlled trial.
                Twenty centres caring for low risk pregnant women.
                4187 women were randomly assigned to umbilical Doppler between 28 and 34 weeks of gestation or no routine umbilical Doppler. The women included were at low risk at 28 weeks of gestation defined by a normal ultrasonographic examination at the time of randomisation and no obstetric or medical complications during the first two trimesters of the pregnancy.
                The general characteristics at inclusion were comparable for the two groups. Performance of umbilical Doppler led to a significant increase in the number of ultrasonographic and Doppler examinations subsequently conducted; there were no other effects on the management of the pregnancy. There was no significant difference in fetal distress during labour (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.70-1.33). There were three times fewer perinatal deaths in the Doppler group (three versus nine), but this difference was not significant (OR 0.33; 95% CI 0.06-1.33).
                Based on this trial routine use of umbilical doppler for low risk pregnancy cannot be recommended. More data are needed to reach a definite conclusion of the value of routine Doppler. To help answer the question: should Doppler ultrasound of the umbilical circulation be made available to all pregnant women as part of their routine antenatal care?
                A randomised trial.
                St James's University Hospital, Leeds.
                2025 low risk primigravid women.
                Obstetric intervention rates and short term neonatal morbidity.
                The incidence of abnormal Doppler was low (1.7%) with complete absence of end diastolic flow in only 0.3% of cases. No significant differences could be demonstrated between control and study women in any of the outcomes measured.
                This study did not demonstrate any benefit or harm from Doppler ultrasound as a routine screening test for all low risk women, whereas our previous studies have suggested that it is useful in high risk pregnancies. Any marginal returns on extending access to Doppler ultrasound from high risk to all women must be small. Since this test has excellent performance characteristics (sensitivity and specificity) for the prediction of fetal hypoxia and acidosis our results call into question the cost to benefit ratio of all tests designed to predict these outcomes in low risk women.
Present evidence failed to show any benefit to either the baby or the mother when utero-placental Doppler ultrasound was used in the second trimester of pregnancy in women at low risk for hypertensive disorders. Nevertheless, this evidence cannot be considered conclusive with only two studies included. There were no randomised studies in the first trimester, or in women at high risk. More research is needed to investigate whether the use of utero-placental Doppler ultrasound may improve pregnancy outcome.