A randomised controlled trial of Doppler ultrasound velocimetry of the umbilical artery in low risk pregnancies. Doppler French Study Group. The effect of introduction of umbilical Doppler recordings to obstetric practice. The Doppler assessment in multiple pregnancy randomised controlled trial of ultrasound biometry versus umbilical artery Doppler ultrasound and biometry in twin pregnancy. 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 assess the effect on obstetric practice of clinician access to umbilical artery Doppler ultrasound results.
                Randomised controlled trial.
                A large teaching hospital.
                Two thousand two hundred and eighty-nine pregnancies defined as being at risk by referral for Doppler or fetal monitoring.
                Continuous wave Doppler studies of umbilical artery. Results immediately available to clinicians.
                Fetal outcome: perinatal mortality, Apgar score and admission to the neonatal unit. Obstetric intervention: admission to hospital, induction of labour and caesarean section. Use of of fetal well being: cardiotocography, biophysical profile and ultrasound biometry.
                The treatment and control groups were comparable in age, parity, gestation at point of entry and risk features. There were no overall differences in perinatal outcome, obstetric intervention or use of fetal monitoring. Examination of a subset recruited only because of hypertension or suspected intrauterine growth retardation (n = 754) similarly showed no difference attributable to group randomisation. Comparison of only those pregnancies retrospectively defined as low risk and high risk showed more use of cardiotocography in the high risk group with access to Doppler (P = 0.007) but no difference in the low risk group.
                Doppler umbilical artery recording has been shown to perform well in prediction power of antenatal fetal compromise. What has been examined in this study is the response of clinicians to the test. The results suggest that obstetricians do not use the test to modify their risk assessment, and, therefore, the need for fetal monitoring in particular pregnancies. There is a real need for accumulation of information from very large data sets, particularly in the prediction power of Doppler for antenatal fetal compromise from apparently chronic utero-placental cause to guide use of monitoring resources. If simply added to existing fetal monitoring techniques in a hospital where these are widely used, then umbilical artery Doppler recordings may at present simply involve extra resources of staff and expenses, without benefit. To assess the addition value of umbilical artery Doppler ultrasound added to standard ultrasound biometry measurements in the management of twin pregnancies.
                A prospective randomised controlled multicentre trial of women with twin pregnancies.
                Tertiary level referral hospitals in Australia, New Zealand and Southeast Asia.
                Pregnant women with twin pregnancies.
                Women were randomised at 25 weeks of gestation to receive either standard ultrasound biometric assessment or standard assessment plus Doppler ultrasound umbilical artery flow velocity waveform analysis. The studies were repeated at 30 and 35 weeks unless otherwise indicated. Physicians were advised to institute close fetal surveillance in the presence of an abnormal umbilical artery Doppler study or with biometry indicators of fetal compromise.
                Standard obstetric (mode of delivery, perinatal mortality, hypertension, antenatal admissions and gestation at delivery) and neonatal (5 minute Apgar scores <5, admissions to neonatal nursery and requirements for ventilation) outcomes and statistical analysis was on intention-to-treat. There were no significant differences between the two groups with respect to demography, antenatal, peripartum and neonatal outcomes. There was no difference in the perinatal mortality rate in the no Doppler group (n = 264), which was 11/1000 live births, and the Doppler group (n = 262), which was 9/1000 live births. There were three unexplained intrauterine deaths in the no Doppler group and none in the Doppler group (OR 0.14, 95% CI 0.01-1.31). Two intrauterine deaths in the Doppler group were due to cord prolapse in labour and a fetomaternal haemorrhage, both very unlikely to be influenced by Doppler surveillance.
                In this study, close surveillance in twin pregnancy resulted in a lower than expected fetal mortality from 25 weeks of gestation in both the no Doppler and Doppler groups. The lower rate of unexplained fetal death in the no Doppler group was not significantly different from the Doppler group. 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.
Existing evidence does not provide conclusive evidence that the use of routine umbilical artery Doppler ultrasound, or combination of umbilical and uterine artery Doppler ultrasound in low-risk or unselected populations benefits either mother or baby. Future studies should be designed to address small changes in perinatal outcome, and should focus on potentially preventable deaths.