Randomized comparison of routine vs highly selective use of Doppler ultrasound and biophysical scoring to investigate high risk pregnancies

Antepartum Fetal Surveillance: ACOG Practice Bulletin, Number 229

The goal of antepartum fetal surveillance is to reduce the risk of stillbirth. Antepartum fetal surveillance techniques based on assessment of fetal heart rate (FHR) patterns have been in clinical use for almost four decades and are used along with real-time ultrasonography and umbilical artery Doppler velocimetry to evaluate fetal well-being. Antepartum fetal surveillance techniques are routinely used to assess the risk of fetal death in pregnancies complicated by preexisting maternal conditions (eg, diabetes mellitus) as well as those in which complications have developed (eg, fetal growth restriction). The purpose of this document is to provide a review of the current indications for and techniques of antepartum fetal surveillance and outline management guidelines for antepartum fetal surveillance that are consistent with the best scientific evidence.

Fetal and umbilical Doppler ultrasound in high-risk pregnancies

BACKGROUND

Abnormal blood flow patterns in fetal circulation detected by Doppler ultrasound may indicate poor fetal prognosis. It is also possible that false positive Doppler ultrasound findings could lead to adverse outcomes from unnecessary interventions, including preterm delivery.

OBJECTIVES

The objective of this review was to assess the effects of Doppler ultrasound used to assess fetal well-being in high-risk pregnancies on obstetric care and fetal outcomes.

SEARCH METHODS

We updated the search of Cochrane Pregnancy and Childbirth's Trials Register on 31 March 2017 and checked reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in high-risk pregnancies compared with no Doppler ultrasound. Cluster-randomised trials were eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked. We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

Nineteen trials involving 10,667 women were included. Risk of bias in trials was difficult to assess accurately due to incomplete reporting. None of the evidence relating to our main outcomes was graded as high quality. The quality of evidence was downgraded due to missing information on trial methods, imprecision in risk estimates and heterogeneity. Eighteen of these studies compared the use of Doppler ultrasound of the umbilical artery of the unborn baby with no Doppler or with cardiotocography (CTG). One more recent trial compared Doppler examination of other fetal blood vessels (ductus venosus) with computerised CTG.The use of Doppler ultrasound of the umbilical artery in high-risk pregnancy was associated with fewer perinatal deaths (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.52 to 0.98, 16 studies, 10,225 babies, 1.2% versus 1.7 %, number needed to treat (NNT) = 203; 95% CI 103 to 4352, evidence graded moderate). The results for stillbirths were consistent with the overall rate of perinatal deaths, although there was no clear difference between groups for this outcome (RR 0.65, 95% CI 0.41 to 1.04; 15 studies, 9560 babies, evidence graded low). Where Doppler ultrasound was used, there were fewer inductions of labour (average RR 0.89, 95% CI 0.80 to 0.99, 10 studies, 5633 women, random-effects, evidence graded moderate) and fewer caesarean sections (RR 0.90, 95% CI 0.84 to 0.97, 14 studies, 7918 women, evidence graded moderate). There was no comparative long-term follow-up of babies exposed to Doppler ultrasound in pregnancy in women at increased risk of complications.No difference was found in operative vaginal births (RR 0.95, 95% CI 0.80 to 1.14, four studies, 2813 women), nor in Apgar scores less than seven at five minutes (RR 0.92, 95% CI 0.69 to 1.24, seven studies, 6321 babies, evidence graded low). Data for serious neonatal morbidity were not pooled due to high heterogeneity between the three studies that reported it (1098 babies) (evidence graded very low).The use of Doppler to evaluate early and late changes in ductus venosus in early fetal growth restriction was not associated with significant differences in any perinatal death after randomisation. However, there was an improvement in long-term neurological outcome in the cohort of babies in whom the trigger for delivery was either late changes in ductus venosus or abnormalities seen on computerised CTG.

AUTHORS' CONCLUSIONS

Current evidence suggests that the use of Doppler ultrasound on the umbilical artery in high-risk pregnancies reduces the risk of perinatal deaths and may result in fewer obstetric interventions. The results should be interpreted with caution, as the evidence is not of high quality. Serial monitoring of Doppler changes in ductus venosus may be beneficial, but more studies of high quality with follow-up including neurological development are needed for evidence to be conclusive.

Role of the fetoplacental endothelium in fetal growth restriction with abnormal umbilical artery Doppler velocimetry

Growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery are at substantially increased risk for adverse perinatal and long-term outcome, even in comparison to growth-restricted fetuses with preserved end-diastolic velocities. Translational studies show that this Doppler velocimetry correlates with fetoplacental blood flow, with absent or reversed end-diastolic velocities signifying abnormally elevated resistance within the placental vasculature. The fetoplacental vasculature is unique in that it is not subject to autonomic regulation, unlike other vascular beds. Instead, humoral mediators, many of which are synthesized by local endothelial cells, regulate placental vascular resistance. Existing data demonstrate that in growth-restricted pregnancies complicated by absent or reversed umbilical artery end-diastolic velocities, an imbalance in production of these vasoactive substances occurs, favoring vasoconstriction. Morphologically, placentas from these pregnancies also demonstrate impaired angiogenesis, whereby vessels within the terminal villi are sparsely branched, abnormally thin, and elongated. This structural deviation from normal placental angiogenesis restricts blood flow and further contributes to elevated fetoplacental vascular resistance. Although considerable work has been done in the field of fetoplacental vascular development and function, much remains unknown about the mechanisms underlying impaired development and function of the human fetoplacental vasculature, especially in the context of severe fetal growth restriction with absent or reversed umbilical artery end-diastolic velocities. Fetoplacental endothelial cells are key regulators of angiogenesis and vasomotor tone. A thorough understanding of their role in placental vascular biology carries the significant potential of discovering clinically relevant and innovative approaches to prevention and treatment of fetal growth restriction with compromised umbilical artery end-diastolic velocities.

Fetal and umbilical Doppler ultrasound in high-risk pregnancies

BACKGROUND

Abnormal blood flow patterns in fetal circulation detected by Doppler ultrasound may indicate poor fetal prognosis. It is also possible false positive Doppler ultrasound findings could encourage inappropriate early delivery.

OBJECTIVES

The objective of this review was to assess the effects of Doppler ultrasound used to assess fetal well-being in high-risk pregnancies on obstetric care and fetal outcomes.

SEARCH METHODS

We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 30 September 2013.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in high-risk pregnancies compared with no Doppler ultrasound.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked.

MAIN RESULTS

Eighteen completed studies involving just over 10,000 women were included. The trials were generally of unclear quality with some evidence of possible publication bias. The use of Doppler ultrasound in high-risk pregnancy was associated with a reduction in perinatal deaths (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.52 to 0.98, 16 studies, 10,225 babies, 1.2% versus 1.7 %, number needed to treat (NNT) = 203; 95% CI 103 to 4352). There were also fewer inductions of labour (average RR 0.89, 95% CI 0.80 to 0.99, 10 studies, 5633 women, random-effects) and fewer caesarean sections (RR 0.90, 95% CI 0.84 to 0.97, 14 studies, 7918 women). No difference was found in operative vaginal births (RR 0.95, 95% CI 0.80 to 1.14, four studies, 2813 women), nor in Apgar scores less than seven at five minutes (RR 0.92, 95% CI 0.69 to 1.24, seven studies, 6321 babies).

AUTHORS' CONCLUSIONS

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.

The role of doppler ultrasound in high risk pregnancy: A comparative study

Background:

The objective was to determine the effectiveness of Doppler velocimetry results in the management of high-risk pregnancy.

Materials and Methods:

This cohort study was conducted from January 2005 to December 2006 in Obstetrics and Gynecology Department of Alnoor Specialist Hospital, Makkah, Saudi Arabia. A total of 200 high-risk pregnant women with gestational age >28 weeks were selected for the study and divided into group A (100) subjected to Doppler velocimetry and group B (100) without Doppler velocimetry. Standard management protocols were followed in all cases. The primary outcome measures were mode of delivery and gestational age at the time of delivery. The secondary outcome measures were prenatal and neonatal complications. Data were analyzed using SPSS version 16 (SPSS Inc., Chicago, IL, USA).

Results:

Preterm deliveries, preterm as well as full-term neonatal admissions were more frequent in group A than those in group B, i.e., (39% vs. 26%), (56% vs. 88%) (OR 0.2, 95% CI 0.04-0.7), and (30% vs. 57%) (OR 0.3, 95% CI 0.2-0.7), respectively. Similarly preterm and full-term neonatal deaths were rare in group A than those in group B, i.e., (9% vs. 78%) (OR 0.1, 95% CI 0.02-0.7), and (6% vs. 29%) (OR 0.2, 95% CI 0.03-1.8), respectively. Emergency caesarean section rate was rare in the subjects with normal Doppler than those with abnormal Doppler (48% vs. 100%) (OR 0.1, 95% CI 0.03-0.4) as well as in group B (48% vs. 82%) (OR 0.2, 95% CI 0.1-0.4).

Conclusion:

Doppler studies in high-risk pregnancies are more beneficial in the management of perinatal as well as neonatal management.

Screening and triage of intrauterine growth restriction (IUGR) in general population and high risk pregnancies: a systematic review with a focus on reduction of IUGR related stillbirths

BACKGROUND

There is a strong association between stillbirth and fetal growth restriction. Early detection and management of IUGR can lead to reduce related morbidity and mortality. In this paper we have reviewed effectiveness of fetal movement monitoring and Doppler velocimetry for the detection and surveillance of high risk pregnancies and the effect of this on prevention of stillbirths. We have also reviewed effect of maternal body mass index (BMI) screening, symphysial-fundal height measurement and targeted ultrasound in detection and triage of IUGR in the community.

METHODS

We systematically reviewed all published literature to identify studies related to our interventions. We searched PubMed, Cochrane Library, and all World Health Organization Regional Databases and included publications in any language. Quality of available evidence was assessed using GRADE criteria. Recommendations were made for the Lives Saved Tool (LiST) based on rules developed by the Child Health Epidemiology Group. Given the paucity of evidence related to the effect of detection and management of IUGR on stillbirths, we undertook Delphi based evaluation from experts in the field.

RESULTS

There was insufficient evidence to recommend against or in favor of routine use of fetal movement monitoring for fetal well being. (1) Detection and triage of IUGR with the help of (1a) maternal BMI screening, (1b) symphysial-fundal height measurement and (1c) targeted ultrasound can be an effective method of reducing IUGR related perinatal morbidity and mortality. Pooled results from sixteen studies shows that Doppler velocimetry of umbilical and fetal arteries in 'high risk' pregnancies, coupled with the appropriate intervention, can reduce perinatal mortality by 29 % [RR 0.71, 95 % CI 0.52-0.98]. Pooled results for impact on stillbirth showed a reduction of 35 % [RR 0.65, 95 % CI 0.41-1.04]; however, the results did not reach the conventional limits of statistical significance. This intervention could be potentially recommended for high income settings or middle income countries with improving rates and standards of facility based care. Based on the Delphi, a combination of screening with maternal BMI, Symphysis fundal height and targeted ultrasound followed by the appropriate management could potentially reduce antepartum and intrapartum stillbirth by 20% respectively. This estimate is presently being recommended for inclusion in the LiST.

CONCLUSION

There is insufficient evidence to recommend in favor or against fetal movement counting for routine use for testing fetal well being. Doppler velocimetry of umbilical and fetal arteries and appropriate intervention is associated with 29 % (95 % CI 2% to 48 %) reduction in perinatal mortality. Expert opinion suggests that detection and management of IUGR with the help of maternal BMI, symphysial-fundal height measurement and targeted ultrasound could be effective in reducing IUGR related stillbirths by 20%.

Umbilical artery Doppler in the assessment of fetal growth restriction

Antepartum fetal surveillance with Doppler ultrasound of umbilical artery has shown significant diagnostic efficacy in identifying fetal compromise in pregnancies complicated with fetal growth restriction (FGR). Its effectiveness in decreasing perinatal mortality has been shown by randomized clinical trials (Level I evidence). This test is the only antepartum fetal test that has shown this level of effectiveness and should be the standard of practice in managing FGR (Level A recommendation). The overall management considerations should encompass other standard fetal monitoring tests (Level B and C recommendations).

Utero-placental Doppler ultrasound for improving pregnancy outcome

BACKGROUND

Impaired placentation can cause some of the most important obstetrical complications such as pre-eclampsia and intrauterine growth restriction and has been linked to increased fetal morbidity and mortality. The failure to undergo physiological trophoblastic vascular changes is reflected by the high impedance to the blood flow at the level of the uterine arteries. Doppler ultrasound study of utero-placental blood vessels, using waveform indices or notching, may help to identify the 'at-risk' women in the first and second trimester of pregnancy, such that interventions might be used to reduce maternal and fetal morbidity and/or mortality.

OBJECTIVES

To assess the effects on pregnancy outcome, and obstetric practice, of routine utero-placental Doppler ultrasound in first and second trimester of pregnancy in pregnant women at high and low risk of hypertensive complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2010) and the reference lists of identified studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of utero-placental vessel waveforms in first and second trimester compared with no Doppler ultrasound. We have excluded studies where uterine vessels have been assessed together with fetal and umbilical vessels.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry.

MAIN RESULTS

We found two studies involving 4993 participants. The methodological quality of the trials was good. Both studies included women at low risk for hypertensive disorders, with Doppler ultrasound of the uterine arteries performed in the second trimester of pregnancy. In both studies, pathological finding of uterine arteries was followed by low-dose aspirin administration.We identified no difference in short-term maternal and fetal clinical outcomes.We identified no randomised studies assessing the utero-placental vessels in the first trimester or in women at high risk for hypertensive disorders.

AUTHORS' CONCLUSIONS

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.

Fetal and umbilical Doppler ultrasound in high-risk pregnancies

BACKGROUND

Abnormal blood flow patterns in fetal circulation detected by Doppler ultrasound may indicate poor fetal prognosis. It is also possible false positive Doppler ultrasound findings could encourage inappropriate early delivery.

OBJECTIVES

The objective of this review was to assess the effects of Doppler ultrasound used to assess fetal well-being in high-risk pregnancies on obstetric care and fetal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009) and the reference lists of identified studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in high-risk pregnancies compared to no Doppler ultrasound.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked.

MAIN RESULTS

Eighteen completed studies involving just over 10,000 women were included. The trials were generally of unclear quality with some evidence of possible publication bias. The use of Doppler ultrasound in high-risk pregnancy was associated a reduction in perinatal deaths (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.52 to 0.98, 16 studies, 10,225 babies, 1.2% versus 1.7 %, numbers needed to treat = 203; 95%CI 103 to 4352). There were also fewer inductions of labour (average RR 0.89, 95% CI 0.80 to 0.99, 10 studies, 5633 women, random effects) and fewer caesarean sections (RR 0.90, 95% CI 0.84 to 0.97, 14 studies, 7918 women). No difference was found in operative vaginal births (RR 0.95, 95% CI 0.80 to 1.14, four studies, 2813 women) nor in Apgar scores less than seven at five minutes (RR 0.92, 95% CI 0.69 to 1.24, seven studies, 6321 babies).

AUTHORS' CONCLUSIONS

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.

WITHDRAWN. Doppler ultrasound for fetal assessment in high risk pregnancies

BACKGROUND

Abnormal waveforms from Doppler ultrasound may indicate poor fetal prognosis. It is also possible that Doppler ultrasound could encourage inappropriate early delivery.

OBJECTIVES

The objective of this review was to assess the effects of Doppler ultrasound in high risk pregnancies on obstetric care and fetal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register. Date of last search: June 2001.

SELECTION CRITERIA

Randomised trials of Doppler ultrasound for the investigation of umbilical artery waveforms in high risk pregnancies compared to no Doppler ultrasound.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted by both reviewers. Study authors were contacted for additional information.

MAIN RESULTS

Eleven studies involving nearly 7000 women were included. The trials were generally of good quality. Compared to no Doppler ultrasound, Doppler ultrasound in high risk pregnancy (especially those complicated by hypertension or presumed impaired fetal growth) was associated with a trend to a reduction in perinatal deaths (odds ratio 0.71, 95% confidence interval 0.50 to 1.01). The use of Doppler ultrasound was also associated with fewer inductions of labour (odds ratio 0.83, 95% confidence interval 0.74 to 0.93) and fewer admissions to hospital (odds ratio 0.56, 95% 0.43 to 0.72), without reports of adverse effects. No difference was found for fetal distress in labour (odds ratio 0.81, 95% confidence interval 0.59 to 1.13) or caesarean delivery (odds ratio 0.94, 95% 0.82 to 1.06).

AUTHORS' CONCLUSIONS

The use of Doppler ultrasound in high risk pregnancies appears to improve a number of obstetric care outcomes and appears promising in helping to reducing perinatal deaths.

Evaluation of the use of umbilical artery Doppler flow studies and outcome of pregnancies at a secondary hospital

OBJECTIVE

To investigate the use of a personal computer (PC)-based, continuous-wave Doppler machine by a trained midwife at a secondary hospital to assess umbilical artery flow velocity waveforms (FVW) in referred women.

METHODS

Pregnant women referred for suspected poor fetal growth were evaluated from June 2002 through December 2004. The Umbiflow apparatus, consisting of a Pentium 3 PC with an ultrasound transducer plugged into the USB port and software, was used to analyze the FVW of the umbilical artery. Pregnancies in which the resistance index (RI) was <75(th) percentile (P75) were not further evaluated for fetal well-being unless the clinical condition of the mother changed. Pregnancies with an RI >or=P75 were followed up according to a specific protocol. Primary end points were intrauterine death and intrauterine growth restriction.

RESULTS

A total of 572 singleton pregnancies were followed up. Significantly more infants were small-for-gestational-age when the RI was >P95 (55.6%) than those between P75 and P95 (41.2%) or <P75 (27.2%). Perinatal mortality rates were 13.2, 39.1 and 41.7 for women with RIs <P75, P75-95 and >P95, respectively.

CONCLUSIONS

A normal Doppler FVW of the umbilical artery is less likely to be followed by perinatal death.

Biophysical profile for fetal assessment in high risk pregnancies

BACKGROUND

A biophysical profile (BPP) includes ultrasound monitoring of fetal movements, fetal tone and fetal breathing, ultrasound assessment of liquor volume with or without assessment of the fetal heart rate. The BPP is performed in an effort to identify babies that may be at risk of poor pregnancy outcome, so that additional assessments of wellbeing may be performed, or labour may be induced or a caesarean section performed to expedite birth.

OBJECTIVES

To assess the effects of the BPP when compared with conventional monitoring (CTG only or MBPP) on pregnancy outcome in high-risk pregnancies.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (October 2007), CENTRAL (The Cochrane Library 2006, Issue 4), MEDLINE (1966 to November 2006), EMBASE (1974 to November 2006) and CINAHL (1980 to November 2006).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving a comparison of fetal BPP with other forms of antepartum fetal assessment in women with high-risk pregnancies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility, quality and extracted data.

MAIN RESULTS

We included five trials, involving 2974 women. Most trials were not of high quality. Although the overall incidence of adverse outcomes was low, available evidence from randomised controlled trials does not support the use of BPP as a test of fetal wellbeing in high-risk pregnancies. We found no significant differences between the groups in perinatal deaths (relative risk (RR) 1.33, 95% confidence interval (CI) 0.60 to 2.98) or in Apgar score less than seven at five minutes (RR 1.27, 95% CI 0.85 to 1.92). Combined data from the two high-quality trials suggest an increased risk of caesarean section in the BPP group RR 1.60, 95% CI 1.05 to 2.44, n = 280, interaction test P = 0.03. However, the number of participating women was relatively small (n = 280). Therefore, additional evidence is required in order to be definitive regarding the efficacy of this test in high-risk pregnancies. Furthermore, the impact of the BPP on other interventions, length of hospitalisation, serious short-term and long-term neonatal morbidity and parental satisfaction requires further evaluation.

AUTHORS' CONCLUSIONS

At present, there is insufficient evidence from randomised trials to support the use of BPP as a test of fetal wellbeing in high-risk pregnancies.

Management of Fetal Growth Restriction: An Evidence-Based Approach

This review provides an evidence-based approach to the management of fetal growth restriction (FGR). The management consists of the following components: appropriate fetal surveillance, timely intervention, and selective etiological management. Umbilical arterial (UA) Doppler sonography is the primary test. Supplementary tests include nonstress test (NST), amniotic fluid assessment, biophysical profile (BPP), and selective venous Doppler sonography. Ominous signs include UA absent or reverse end-diastolic flow, non-assuring NST, low BPP, and abnormal fetal venous flow patterns. An evidence-based clinical management guideline is included and individualization of care is recommended.

Assessing fetal health

Fetal surveillance significantly reduces the incidence of fetal loss, perinatal morbidity and maternal distress. Obstetricians traditionally classify pregnancies as 'low' or 'high risk' and apply various methods of fetal surveillance in the latter group. However, the majority of stillbirths now occur in 'low-risk' women. This seemingly anomalous observation emphasises the need to develop more effective ways of identifying 'at-risk' fetuses in 'low-risk' women. This chapter describes and critically evaluates eleven currently available tools for fetal surveillance. It also reviews the criteria for ascribing risk status in pregnancy and suggests a pragmatic approach to health assessment in normally formed fetuses for each group. It does not address fetal surveillance during labour and delivery.

A critical appraisal of the use of umbilical artery Doppler ultrasound in high-risk pregnancies: use of meta-analyses in evidence-based obstetrics

OBJECTIVES

To reanalyze randomized controlled trials on the use of umbilical artery Doppler velocimetry in high-risk pregnancies and determine which high-risk pregnancies benefit from the use of Doppler velocimetry.

METHODS

Searching Medline, the Cochrane Library and Embase we found 13 randomized controlled trials on the use of Doppler velocimetry in high-risk pregnancies. Of these, six included pregnancies with strictly defined suspected intrauterine growth restriction and/or hypertensive disease of pregnancy ('well-defined studies'); the rest included a great variety of high-risk pregnancies ('general risk studies'). The studies were analyzed with particular regard to the heterogeneity and to outcome. Audits of the perinatal deaths reported in the randomized controlled trials were performed by a panel of 32 international experts.

RESULTS

The 'well-defined studies' had a more uniform study design as compared to the 'general risk studies' and they showed a significant reduction in antenatal admissions (odds ratio, 0.56; 95% confidence interval, 0.43-0.72), inductions of labor (0.78; 0.63-0.96), elective deliveries (inductions of labor and elective Cesarean sections) (0.73; 0.61-0.88) and Cesarean sections (0.78; 0.65-0.94). By perinatal audit it was found that more perinatal deaths in the 'well-defined studies' were potentially avoidable by use of Doppler velocimetry ( P < 0.0005) and the rate of avoidable perinatal deaths was higher among controls (50%) than cases (20%) in this group.

CONCLUSION

The randomized controlled trials on umbilical artery Doppler velocimetry show major differences regarding study design and technical and clinical issues and, therefore, they should not be pooled in a simple meta-analysis. By stratification it was found that only in pregnancies with suspected intrauterine growth restriction and/or hypertensive disease of pregnancy will the use of umbilical artery Doppler velocimetry reduce the number of perinatal deaths and unnecessary obstetric interventions.

Doppler ultrasound for fetal assessment in high risk pregnancies

BACKGROUND

Abnormal waveforms from Doppler ultrasound may indicate poor fetal prognosis. It is also possible that Doppler ultrasound could encourage inappropriate early delivery.

OBJECTIVES

The objective of this review was to assess the effects of Doppler ultrasound in high risk pregnancies on obstetric care and fetal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register.

SELECTION CRITERIA

Randomised trials of Doppler ultrasound for the investigation of umbilical artery waveforms in high risk pregnancies compared to no Doppler ultrasound.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted by both reviewers. Study authors were contacted for additional information.

MAIN RESULTS

Eleven studies involving nearly 7000 women were included. The trials were generally of good quality. Compared to no Doppler ultrasound, Doppler ultrasound in high risk pregnancy (especially those complicated by hypertension or presumed impaired fetal growth) was associated with a trend to a reduction in perinatal deaths (odds ratio 0.71, 95% confidence interval 0.50 to 1.01). The use of Doppler ultrasound was also associated with fewer inductions of labour (odds ratio 0.83, 95% confidence interval 0.74 to 0.93) and fewer admissions to hospital (odds ratio 0.56, 95% 0.43 to 0.72), without reports of adverse effects. No difference was found for fetal distress in labour (odds ratio 0.81, 95% confidence interval 0.59 to 1.13) or caesarean delivery (odds ratio 0.94, 95% 0.82 to 1.06).

REVIEWER'S CONCLUSIONS

The use of Doppler ultrasound in high risk pregnancies appears to improve a number of obstetric care outcomes and appears promising in helping to reducing perinatal deaths.

Randomised controlled trial of cardiotocography versus umbilical artery Doppler in the management of small for gestational age fetuses

OBJECTIVE

To compare the impact on use of resources in the management of small for gestational age babies using Doppler ultrasound versus cardiotocography.

DESIGN

A randomised controlled trial.

SETTING

A large district general hospital delivering 5500 to 6000 infants each year, 30% to 35% of which are to women of Pakistani origin.

POPULATION

One hundred and fifty women delivered of small for gestational age infants.

MAIN OUTCOME MEASURES

Primary outcome measures were length of hospital inpatient stay and induction of labour rates. Secondary outcome measures included caesarean section rates and length of stay on neonatal unit.

RESULTS

The use of Doppler reduced average hospital inpatient stay from 2.5 days to 1.1 days, compared with cardiotocography (P = 0.036). There was no effect on induction of labour rates or caesarean section rates. There was no significant difference in length of stay on the neonatal unit (P = 0.33). There was a reduction in monitoring frequency and fewer hospital antenatal clinic visits.

CONCLUSION

The use of Doppler ultrasound to manage small for gestational age infants reduces the use of resources, compared with cardiotocography.

Recent advances. Obstetrics

Images

Elaboration of stem villous vessels in growth restricted pregnancies with abnormal umbilical artery Doppler waveforms

OBJECTIVE

To assess the elaboration of placental stem villous vessels from pregnancies complicated by intrauterine growth restriction (IUGR) with absent end-diastolic flow velocity detected prior to delivery in the umbilical artery.

DESIGN

Comparison between IUGR and control groups of the distribution, in 15 microns increments of 600 randomly chosen stem vessel profiles (post-fixation diameter 10-160 microns) identified by immunohistochemical localisation of alpha-smooth muscle actin in the vessel media.

SETTING

Clinical teaching hospital and university anatomy department.

SUBJECTS

Paraffin-fixed blocks obtained from placentas of eight pregnancies complicated by IUGR and eight gestational age-matched controls.

RESULTS

The distribution of the stem villous vessels in the IUGR placentas, as assessed by the mean vessel diameter in each case, did not differ from the controls (mean vessel diameter 31.8 microns [SD 2.4] vs 29.6 microns [2.3]; P = 0.13). In five IUGR cases alpha-smooth muscle actin positive cells (myofibroblasts) were identified within the stroma of nonmuscularised peripheral (mature intermediate and terminal) villi, but in none of the controls.

CONCLUSIONS

Our data do not support the theory that IUGR with absent end-diastolic flow velocity in the umbilical artery is due to a selective loss of small stem villous vessels. The increased impedance in this condition may be conferred more distally within the nonmuscularised capillaries of the peripheral villi.

Doppler ultrasonography in high-risk pregnancies: systematic review with meta-analysis

OBJECTIVE

Our objective was to review all available (published and unpublished) randomized controlled trials of Doppler ultrasonography of the umbilical artery in high-risk pregnancies.

STUDY DESIGN

Only completed randomized controlled trials were included and reviewed according to the prespecified protocol. Data were sought for 24 prespecified perinatal outcomes. All meta-analyses were based on the "intention to treat." Primary outcome was defined as perinatal death (any death in utero or postnatally recorded during duration of individual randomized controlled trial). Reported perinatal outcomes that were not prespecified were meta-analyzed on a post hoc basis.

RESULTS

Twenty randomized controlled trials of Doppler ultrasonography were identified; 12 fulfilled the prespecified criteria. Meta-analysis shows a significant reduction in the number of antenatal admissions (44%, 95% confidence interval 28% to 57%), inductions of labor (20%, 95% confidence interval 10% to 28%), and cesarean sections for fetal distress (52%, 95% confidence interval 24% to 69%) in the Doppler group and that the clinical action guided by Doppler ultrasonography reduces the odds of perinatal death by 38% (95% confidence interval 15% to 55%). The reduction in perinatal deaths was also observed in five mortality subgroups (i.e., stillbirths, neonatal deaths, deaths of normally formed babies, normally formed stillbirths, and deaths of normally formed neonates). Post hoc analyses revealed a statistically significant reduction in elective delivery, intrapartum fetal distress, and hypoxic encephalopathy in the Doppler group.

CONCLUSION

There is now compelling evidence that women with high-risk pregnancies, including preeclampsia and suspected intrauterine growth retardation, should have access to Doppler ultrasonographic study of umbilical artery waveforms.

Glycoprotein and ganglioside changes in human trophoblasts after exposure to pulsed Doppler ultrasound

Changes in glycoprotein and ganglioside composition in human trophoblasts (eighth week of gestation) after in vitro exposure to pulsed Doppler ultrasound (pulse duration 1.22 microseconds; repetition frequency 11.1 kHz; center frequency 4 MHz; ISPPA = 175.5 W/cm2; ISPTA = 0.59 W/cm2) were investigated. Evacuated trophoblasts were divided in two halves and insonated for 10 min on top of a 6-cm layer of 5% gelatin in 50-mL tubes (Falcon) at 37 degrees C. One half of each trophoblast was sham insonated and served as an internal control. After insonation trophoblasts were maintained at 37 degrees C for 24 h. Glycoproteins were detected using alpha-D-mannose specific lectins from Galanthus nivalis and Narcissus pseudonarcissus. A decrease in the expression of mannose containing glycoprotein mgp47 and an increase in expression of mgp54 were observed. Ganglioside composition was also significantly altered. Concentrations of two gangliosides migrating similarly to GM2, and one similarly to GQ1, decreased by more than 75%. At the same time, concentrations of one ganglioside migrating similarly to GM3, and two other unidentified gangliosides increased two- to fourfold.

Accuracy of the middle-cerebral-to-umbilical-artery resistance index ratio in the prediction of neonatal outcome in patients at high risk for fetal and neonatal complications

OBJECTIVE

The purpose of this study was to determine the accuracy of the middle-cerebral-to-umbilical-artery resistance index ratio in the prediction of fetal outcome in pregnancies at high risk for fetal and neonatal morbidity and mortality.

STUDY DESIGN

A prospective controlled nonrandomized study was conducted in the high-risk pregnancy unit of a teaching hospital. The control group was formed by 20 healthy women with uncomplicated singleton pregnancies and healthy children delivered at term. The study group consisted of 115 women referred to the high-risk pregnancy unit because of a variety of pregnancy complications. Longitudinal evaluation of the control group and cross-sectional evaluation of the study group were carried out at different gestational ages by means of duplex Doppler ultrasonography. The main outcome measures were fetal growth retardation, preterm birth, and neonatal morbidity.

RESULTS

The middle-cerebral-to-umbilical-artery ratio remains relatively constant (mean +/- SD 1.33 +/- 0.19) between 27 and 37 weeks. A cutoff value of 1.0 (sensitivity 57.9%, specificity 75.6%, false-positive rate 24.4%) was selected from the receiver-operator characteristic curve analysis. This cutoff value successfully identified a population at significant risk of fetal growth retardation (relative risk 3.07, 95% confidence interval 1.73 to 5.45, exact two-tailed p = 0.0009) and severe neonatal morbidity (Mann-Whitney U = 463.5, two-tailed p = 0.03). The middle-cerebral-to-umbilical-artery ratio was not useful in the prediction of preterm birth.

CONCLUSIONS

A middle-cerebral-to-umbilical-artery ratio of < or = 1.0 identifies a subgroup of patients at high risk for fetal growth retardation and severe neonatal morbidity.

Screening for the compromised fetus: a randomized trial of umbilical artery velocimetry in unselected pregnancies

OBJECTIVE

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).

STUDY DESIGN

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.

RESULTS

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).

CONCLUSIONS

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.

Recent advances in the use of Doppler waveform indices in the antenatal assessment of intrauterine growth retardation

Doppler ultrasound has been advocated as a useful tool to evaluate pregnancies with intrauterine growth retardation (IUGR). However, many previous studies have used smallness for gestational age (SGA) at birth to define IUGR. The ability of Doppler ultrasound to predict SGA, neonatal morphometric indices of wasting such as a low ponderal index, and perinatal morbidity is reviewed. Doppler assessment of the umbilical and uteroplacental vasculatures were inferior to ultrasound measurements of fetal size in the prediction of SGA. In low risk fetuses, umbilical artery waveform indices were of limited value in the prediction of neonatal morphometric indices of wasting. Within a group of high risk fetuses, Doppler assessment of the umbilical artery and, in particular, the middle cerebral and aortic vessels, were useful in predicting fetuses with neonatal wasting. Similar findings were noted in the prediction of perinatal morbidity. The review confirms the usefulness of umbilical artery Doppler waveform indices in the antenatal assessment of IUGR. Whilst preliminary studies appear to suggest that Doppler waveform indices of the middle cerebral and aortic vessels may confer an additional advantage in the antenatal assessment of IUGR, randomized controlled trials evaluating their effect on perinatal outcome and studies on the reproducibility of these indices need to be carried out before their widespread introduction into obstetric practice.

The role of Doppler velocimetry in the management of high risk pregnancies

OBJECTIVE

To determine whether knowledge of the result of Doppler velocimetry of the umbilical artery is beneficial to the management of a high risk pregnancy.

DESIGN

Randomised controlled trial. The trial was of the management type, designed to assess benefit accruing from additional information supplied by Doppler velocimetry.

SETTING

Tygerberg Hospital, Cape Town, South Africa. The hospital serves a population from the lower socio-economic groups.

SUBJECTS

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).

INTERVENTIONS

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.

MAIN OUTCOME MEASURES

Perinatal mortality and morbidity, antenatal hospitalisation, maternal intervention, admission to the neonatal intensive care unit and hospitalisation until discharge from the neonatal wards.

RESULTS

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).

The effect of introduction of umbilical Doppler recordings to obstetric practice

OBJECTIVE

To assess the effect on obstetric practice of clinician access to umbilical artery Doppler ultrasound results.

DESIGN

Randomised controlled trial.

SETTING

A large teaching hospital.

SUBJECTS

Two thousand two hundred and eighty-nine pregnancies defined as being at risk by referral for Doppler or fetal monitoring.

INTERVENTIONS

Continuous wave Doppler studies of umbilical artery. Results immediately available to clinicians.

MAIN OUTCOME MEASURES

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.

RESULTS

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.

CONCLUSION

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.

Randomised comparison of routine versus highly selective use of Doppler ultrasound in low risk pregnancies

OBJECTIVE

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?

DESIGN

A randomised trial.

SETTING

St James's University Hospital, Leeds.

SUBJECTS

2025 low risk primigravid women.

MAIN OUTCOME MEASURES

Obstetric intervention rates and short term neonatal morbidity.

RESULTS

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.

CONCLUSION

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.

Early Doppler studies in lupus pregnancy

The management of 56 pregnancies in 54 patients is presented, 52 with systemic lupus erythematosus and two patients with primary antiphospholipid syndrome. All underwent serial Doppler blood flow studies of the umbilical and uterine arteries from 14 weeks of gestation. Drug therapy was directed at disease activity and the fetus and mother monitored intensively to identify optimum time for delivery. End diastolic blood flow (EDF) studies were compared with anticardiolipin antibodies (aCL) and the lupus anticoagulant (LAC) to predict outcome of pregnancy in terms of mortality, Caesarian delivery, hypertension, and gestation. The absence of end-diastolic blood flow predicted Caesarian delivery more accurately. The presence of EDF and the absence of aCL was consistent with a normotensive pregnancy. The presence of LAC was the best of the three in predicting fetal demise.

Doppler flow velocity waveform analysis in high risk pregnancies: a randomized controlled trial

OBJECTIVE

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.

DESIGN

A randomized controlled trial.

SETTING

Department of Ultrasound, King Edward Memorial Hospital, Perth, Western Australia.

SUBJECTS

505 women with pregnancy abnormalities referred to an ultrasound department for fetal investigation during the third trimester.

INTERVENTION

Continuous wave Doppler studies of umbilical and uteroplacental arterial circulations. Results were revealed to patients and clinicians.

MAIN OUTCOME MEASURES

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.

RESULTS

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.

CONCLUSION

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.