Randomised comparison of routine versus highly selective use of Doppler ultrasound in low risk pregnancies. The Doppler assessment in multiple pregnancy randomised controlled trial of ultrasound biometry versus umbilical artery Doppler ultrasound and biometry in twin pregnancy. A randomised controlled trial of Doppler ultrasound velocimetry of the umbilical artery in low risk pregnancies. Doppler French Study Group. Doppler flow velocity waveform analysis in high risk pregnancies: a randomized controlled trial. Randomized comparison of routine vs highly selective use of Doppler ultrasound and biophysical scoring to investigate high risk pregnancies. The effect of introduction of umbilical Doppler recordings to obstetric practice. Doppler ultrasonography in suspected intrauterine growth retardation: a randomized clinical trial. A randomized controlled trial in a hospital population of ultrasound measurement screening for the small for dates baby. Effect of prenatal ultrasound screening on perinatal outcome. RADIUS Study Group. Effects of frequent ultrasound during pregnancy: a randomised controlled trial. Screening for the compromised fetus: a randomized trial of umbilical artery velocimetry in unselected pregnancies. The role of Doppler velocimetry in the management of high risk pregnancies.
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. 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 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 test whether the introduction of Doppler waveform analysis into the ultrasound department of a tertiary level hospital reduces neonatal morbidity and improves obstetric management.
                A randomized controlled trial.
                Department of Ultrasound, King Edward Memorial Hospital, Perth, Western Australia.
                505 women with pregnancy abnormalities referred to an ultrasound department for fetal investigation during the third trimester.
                Continuous wave Doppler studies of umbilical and uteroplacental arterial circulations. Results were revealed to patients and clinicians.
                Principal end point was the duration of neonatal stay in hospital; other end points included the number and type of fetal heart rate monitoring studies, obstetric interventions, frequency of fetal distress, birthweight, Apgar scores and need for neonatal intensive care.
                There was no effect on the duration of neonatal stay in hospital. Small trends in obstetric management were observed with study group patients having fewer contraction stress tests, less likelihood of antepartum fetal distress, and more likelihood of fetal distress after induction of labour leading to emergency caesarean section. Depressed Apgar scores were more frequent in the study group.
                Introduction of Doppler waveform studies did not result in reduced neonatal morbidity but did have a small effect on obstetric management. For each institution the role of Doppler studies in late pregnancy will be influenced by the usage of other tests of fetal welfare already entrenched in clinical practice. To compare routine versus highly selective use of Doppler ultrasound and biophysical scoring in higher risk pregnancy.
                A pragmatic randomized trial.
                St James's University Hospital, Leeds.
                500 pregnant women at high risk of intrauterine growth retardation or still birth.
                Regular monitoring with biophysical profile assessment and Doppler velocity waveform recording in umbilical and uteroplacental arteries. Results immediately available to clinicians.
                Gestational age at delivery, obstetric intervention rates and short-term neonatal morbidity.
                Risk factors were distributed very evenly between the 250 patients in the study and control groups respectively. A total of 902 biophysical profile and Doppler assessments were done in the 250 study group patients and only in 12 patients in the control group. In the study group, absent end-diastolic flow was found in only 2.7% of all 902 measurements. A persistently abnormal biophysical score was always associated with absence of end-diastolic flow. The mean gestational age at induction of labour was statistically and clinically similar in the two groups and there was no overall statistically significant difference in intervention rates between the two groups. There was a statistically significant lower frequency of depressed 5-min Apgar scores in the study group. Serious neonatal morbidity was also statistically significantly more common in the control group than in the study group.
                The use of Doppler ultrasound in higher risk pregnancies does not lead to an increase in iatrogenic preterm delivery. The total rate of positive tests on Doppler ultrasound is very low and persistently abnormal biophysical scores are unlikely to be found in patients where umbilical end-diastolic blood flow is present. Surrogate measures for fetal damage seem to be improved when clinicians have access to Doppler ultrasound assessments. 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. A randomized clinical trial was performed to test the hypothesis that if suspected intrauterine growth retardation (IUGR) is associated with normal umbilical artery Doppler ultrasound findings, hospitalization can safely be avoided. One hundred and fifty women with singleton pregnancies and suspected IUGR were randomized between an intervention (n = 74) and a control group (n = 76). In the intervention group, clinicians were strongly requested not to hospitalize for suspected IUGR if the Doppler findings were normal. In the control group, the Doppler results were not revealed and the participants received the standard management for suspected IUGR. Endpoints of the trial were: costs in terms of hospitalization, perinatal outcome, neurological development, and postnatal growth. Duration of hospitalization was significantly shorter in the intervention group than in the control group. Contrary to expectations, the hospitalization rate during pregnancy in the intervention group was not below that of the control group. This negative finding was partly due to the admission of patients in the intervention group despite their normal Doppler results. Moreover, the trial might have induced a more critical attitude towards hospitalization in suspected IUGR, decreasing admission in the control group. No clear differences were found in perinatal outcome, neurological development, or postnatal growth. The results suggest that normal umbilical artery Doppler findings in suspected cases of IUGR justify outpatient management. Poor fetal growth is an important cause of perinatal mortality and morbidity. Based on the hypothesis that early diagnosis of fetal growth problems leads to more appropriate management and therefore, improved outcome, a randomized controlled trial of ultrasound measurement was performed on 1,528 women booked through a hospital antenatal clinic. This compared a number of perinatal outcomes between the group who had a routine 2-stage examination (early dating and 34-week scan) and a group who had only a dating scan and then additional scans as generated by their clinical situations. No significant differences could be found between the groups when these perinatal outcomes were considered. These results mirror previously published randomized controlled trials. Selection of women for third trimester ultrasound examination for suspected fetal growth problems should be based on careful clinical assessment and should not be routine. Many clinicians advocate routine ultrasound screening during pregnancy to detect congenital anomalies, multiple-gestation pregnancies, fetal growth disorders, placental abnormalities, and errors in the estimation of gestational age. However, it is not known whether the detection of these conditions through screening leads to interventions that improve perinatal outcome.
                We conducted a randomized trial involving 15,151 pregnant women at low risk for perinatal problems to determine whether ultrasound screening decreased the frequency of adverse perinatal outcomes. The women randomly assigned to the ultrasound-screening group underwent one sonographic examination at 15 to 22 weeks of gestation and another at 31 to 35 weeks. The women in the control group underwent ultrasonography only for medical indications, as identified by their physicians. Adverse perinatal outcome was defined as fetal death, neonatal death, or neonatal morbidity such as intraventricular hemorrhage.
                The mean numbers of sonograms obtained per woman in the ultrasound-screening and control groups were 2.2 and 0.6, respectively. The rate of adverse perinatal outcome was 5.0 percent among the infants of the women in the ultrasound-screening group and 4.9 percent among the infants of the women in the control group (relative risk, 1.0; 95 percent confidence interval, 0.9 to 1.2; P = 0.85). The rates of preterm delivery and the distribution of birth weights were nearly identical in the two groups. The ultrasonographic detection of congenital anomalies had no effect on perinatal outcome. There were no significant differences between the groups in perinatal outcome in the subgroups of women with post-date pregnancies, multiple-gestation pregnancies, or infants who were small for gestational age.
                Screening ultrasonography did not improve perinatal outcome as compared with the selective use of ultrasonography on the basis of clinician judgment. Despite widespread application of ultrasound imaging and Doppler blood flow studies, the effects of their frequent and repeated use in pregnancy have not been evaluated in controlled trials. From 2834 women with single pregnancies at 16-20 weeks gestation, 1415 were selected at random to receive ultrasound imaging and continuous-wave Doppler flow studies at 18, 24, 28, 34, and 38 weeks gestation (the intensive group) and 1419 to receive single ultrasound imaging at 18 weeks (the regular group). Outcome data was obtained from 99% of women who entered the study. The only difference between the two groups was significantly higher intrauterine growth restriction in the intensive group, when expressed both as birthweight < 10th centile (relative risk 1.35; 95% confidence interval 1.09 to 1.67; p = 0.006) and birthweight < 3rd centile (relative risk 1.65; 95% confidence intervals 1.09 to 2.49; p = 0.020). While it is possible that this finding was a chance effect, it is also plausible that frequent exposure to ultrasound may have influenced fetal growth. Repeated prenatal ultrasound imaging and Doppler flow examinations should be restricted to those women to whom the information is likely to be of clinical benefit. Meta-analysis of randomized trials of Doppler ultrasonography in high-risk pregnancies has showed reduced mortality rates among normally formed fetuses. This trial addressed the impact on outcome of umbilical artery velocimetry in a nonselected population (i.e., as a screening test in low-risk and high-risk pregnancies).
                A randomized, controlled trial with Doppler ultrasonographic investigation was performed at two gestational age windows: 26 to 30 weeks and 34 to 36 weeks. The 2986 women were randomly allocated to revealed or concealed groups in which the Doppler results were either made available or not made available to clinicians; 1056 women were studied at only the first window, 544 at only the second, and 1386 at both.
                There were no significant differences between groups in antenatal admissions to hospital, preterm deliveries, rates of cesarean section, admission to the neonatal unit, and need for assisted ventilation. There was, however, a trend toward fewer stillbirths in the "revealed" group (three vs eight, odds ratio 0.34, confidence interval 0.10 to 1.07).
                The incidence of stillbirths was reduced by more than half in the Doppler-revealed group, but the confidence intervals were wide and these findings could be compatible with chance. To determine whether knowledge of the result of Doppler velocimetry of the umbilical artery is beneficial to the management of a high risk pregnancy.
                Randomised controlled trial. The trial was of the management type, designed to assess benefit accruing from additional information supplied by Doppler velocimetry.
                Tygerberg Hospital, Cape Town, South Africa. The hospital serves a population from the lower socio-economic groups.
                Women with pregnancies 28 or more weeks gestation with hypertensive diseases and/or suspected small for gestational age fetuses were referred for Doppler velocimetry. From this population, three subsets were formed: 1. those with fetuses with absent end-diastolic velocities (20 fetuses); 2. those with hypertension but with fetuses with end-diastolic velocities (89 fetuses); and 3. those with fetuses suspected of being small for gestational age but with end-diastolic velocities (104 fetuses).
                Doppler velocimetry on all subjects. The study group consisted of 10 cases with absent end-diastolic velocities, 47 cases with hypertensive diseases with end-diastolic velocities and 51 cases with suspected small for gestational age fetuses but with end-diastolic velocities in which the result was revealed to the clinician. The control group consisted of 10, 42 and 53 cases, respectively, in which the Doppler results were not revealed. All other routine investigations (sonar and antenatal fetal heart rate monitoring) were available to the clinicians. Standard management protocols were followed in all groups.
                Perinatal mortality and morbidity, antenatal hospitalisation, maternal intervention, admission to the neonatal intensive care unit and hospitalisation until discharge from the neonatal wards.
                In the study and control groups the gestational age at entry to the study, maternal age, parity and various complications were not significantly different. In the subset with absent end-diastolic velocities, there was one neonatal death in the study group, but in the control group there were six deaths, five intrauterine and one perinatally related infant death (P = 0.029). Because of this significant finding, the study was stopped. There were no differences in outcome in the subset where there was hypertensive disease with end-diastolic velocities between the study and control groups. In the subset in which small for gestational age fetuses were suspected, but in which end-diastolic velocities were present, the women in the study group had significantly fewer days in hospital before delivery (P < 0.001) and tended to have fewer maternal interventions (study group = 27%, control group = 43%; P = 0.07; odds ratio (OR) 0.49, 95% confidence limits (CL) 0.2 and 1.25) and caesarean sections (study group = 13%, control group = 27%; P = 0.08; OR 0.43, 95% CL 0.14 and 1.32). The infants of the study group in this subset also spent significantly less time in the neonatal wards (P = 0.029).
Current evidence suggests that the use of Doppler ultrasound in high-risk pregnancies reduced the risk of perinatal deaths and resulted in less obstetric interventions. The quality of the current evidence was not of high quality, therefore, the results should be interpreted with some caution. Studies of high quality with follow-up studies on neurological development are needed.