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

Extent of absent end-diastolic flow in umbilical artery and outcome of pregnancy

OBJECTIVE

To investigate if the extent of absent end-diastolic flow (AEDF) on umbilical artery (UA) Doppler velocimetry predicts pregnancy outcome.

METHODS

This was a retrospective observational study based on data from 25 000 Doppler examinations of UA flow performed between 1998 and 2017 at the Blood Flow Laboratory, Level III Perinatal Center, Lund, Sweden. All pregnancies with AEDF in the UA were identified, and the duration of AEDF as a proportion of the total duration of the cardiac cycle (T_a /T_tot ratio) was measured in digital images of the Doppler spectrum recorded at the last examination showing AEDF before delivery. Clinical data on pregnancies and neonatal outcomes were extracted from the regional perinatal database and the hospital patient records. The predictive performance of the T_a /T_tot ratio for intrauterine death and any (intrauterine or postnatal) death was assessed.

RESULTS

A total of 170 fetuses (122 (72%) singletons and 48 (28%) twins) were included in the study. Median gestational age at birth was 189.5 days (range, 163-279 days) (i.e. 27 + 0 weeks (range, 23 + 2 to 39 + 6 weeks)), birth weight was 650 g (range, 320-3326 g) and deviation from expected birth weight (standard deviation score) was -2.975 (range, -6.38 to 0.69). There were 15 (9%) intrauterine and 26 (15%) postnatal deaths. The principal outcome variables and their relationship with Doppler velocimetry results did not differ significantly between singletons and twins, giving a rationale for using the T_a /T_tot ratio in the total study group. Mean T_a /T_tot ratio was 0.42 ± 0.08 and 0.34 ± 0.08 in stillborn and liveborn fetuses, respectively (P = 0.002). For fetuses examined before 30 weeks' gestation, a T_a /T_tot ratio cut-off of 0.30 predicted intrauterine death with 92% sensitivity and a negative predictive value (NPV) of 98% (area under receiver-operating-characteristics curve (AUC), 0.74) and predicted any death with 83% sensitivity and a NPV of 85% (AUC, 0.66).

CONCLUSIONS

In fetuses with AEDF in the UA, duration of absent flow for at least 30% of the total cardiac cycle length might predict the risk of fetal demise, even when assessed before 30 weeks' gestation. This finding is particularly relevant to growth-restricted fetuses. After evaluation in further studies, the extent of AEDF might facilitate obstetric decision-making in very preterm growth-restricted fetuses. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Induction of labour with unfavourable local conditions for suspected fetal growth restriction after 36 weeks of gestation: Factors associated with the risk of caesarean

INTRODUCTION

Induction of labour in women with an unfavourable cervix is associated with a risk of caesarean delivery. When a diagnosis of fetal growth restriction (FGR) is also involved, the risk of intrapartum fetal acidosis increases. The main objective was to identify prognostic factors for the risk of caesarean delivery after induction for suspected FGR after 36 weeks of gestation with an unripe cervix.

MATERIAL AND METHODS

This was a retrospective, single-centre (Port Royal, Paris, France) study of women with a singleton fetus in cephalic presentation, with labour induced at or after 36 weeks for suspected FGR diagnosed during second or third trimester of pregnancy with an unripe cervix (Bishop score under 6) who gave birth between 1 January 2015 and 31 December 2019. A multivariable analysis was performed to identify the factors related to an increased risk of caesarean section.

RESULTS

Of the 146 women included, 56 (38.4 %) had caesarean deliveries. After adjustment, the factors significantly associated with the risk of caesarean were maternal age greater than 39 years (ORa = 4.33 [1.22-17.2], reference: 25-39 years), nulliparity (ORa = 3.49 [1.25-11.2]), and an abnormal fetal umbilical artery Doppler velocimetry (ORa = 3.50 [1.47-8.70]). The risk of poor neonatal condition did not differ significantly between women with vaginal and caesarean deliveries (2.3 % vs 7.3 %, P = 0.21).

CONCLUSION

When FGR is suspected at 36 weeks of gestation and later, induction of labour is a reasonable option, even if the cervix is unripe, as the risk of caesarean delivery appears acceptable and neonatal status is good and similar with both modes of delivery.

Cerebroplacental ratio as predictor of adverse perinatal outcome in the third trimester

Introduction

Fetal growth restriction is associated with adverse perinatal outcome and the clinical management of these pregnancies is a challenge. The aim of this study was to investigate the potential of cerebroplacental ratio (CPR) to predict adverse perinatal outcome in high‐risk pregnancies in the third trimester. Another aim was to study whether the CPR has better predictive value than its components, middle cerebral artery (MCA) pulsatility index (PI) and umbilical artery (UA) PI.

Material and methods

The study was a retrospective cohort study including 1573 singleton high‐risk pregnancies with Doppler examinations performed at 32⁺⁰ to 40⁺⁶ gestational weeks at Lund University Hospital and the University Hospital of Malmö between 29 December 1994 and 31 December 2017. Receiver operating characteristics (ROC) curves were used to investigate the predictive value of the gestational age‐specific z‐scores for CPR, UA PI and MCA PI, respectively, for the primary outcome “perinatal asphyxia/mortality” and the secondary outcomes “birthweight small for gestational age (SGA)” and two composite outcomes: “appropriate for gestational age/large for gestational age liveborn infants with neonatal morbidity” and “SGA liveborn infants with neonatal morbidity.”

Results

The performance in predicting perinatal asphyxia/mortality was poor for all three variables and did not differ significantly. The ROC area under curve (AUC) was 0.56, 0.55 and 0.53 for CPR, UA PI and MCA PI z‐scores, respectively. The ROC AUC for CPR z‐scores to predict SGA was 0.73, significantly higher than that for either UA PI or MCA PI (P < .001). The ability of CPR and the MCA PI to predict appropriate for gestational age/large for gestational age infant morbidity and SGA infant morbidity was similar and significantly better than UA PI (P < .001).

Conclusions

In the present study, none of the three Doppler measures proved to be useful in predicting perinatal asphyxia and mortality. CPR and MCA PI were equally good in predicting neonatal morbidity, especially in SGA pregnancies, and both were significantly better predictors than the UA PI. CPR had a high predictive value for SGA at birth, better than that of its two components, UA PI and MCA PI.

Quantification of Wave Reflection in the Human Umbilical Artery From Asynchronous Doppler Ultrasound Measurements

Elevated umbilical artery pulsatility is a widely used biomarker for placental pathology leading to intra-uterine growth restriction and, in severe cases, still-birth. It has been hypothesized that placental pathology modifies umbilical artery pulsatility by altering the degree to which the pulse pressure wave, which originates from the fetal heart, is reflected from the placental vasculature to interfere with the incident wave. Here we present a method for estimating the reflected pulse wave in the umbilical artery of human fetuses using asynchronously acquired Doppler ultrasound measurements from the two ends of the umbilical cord. This approach assumes non-dispersive and loss-less propagation of the waves along the artery and models the reflection process as a linear system with a parameterized impulse response. Model parameters are determined from the measured Doppler waveforms by constrained optimization. Velocity waveforms were obtained from 142 pregnant volunteers where 123 met data quality criteria in at least one umbilical artery. The reflection model was consistent with the measured waveforms in 183 of 212 arteries that were analyzed. The analysis method was validated by applying it to simulated datasets and comparing solutions to ground-truth. With measurement noise levels typical of clinical ultrasound, parameters describing the reflected wave were accurately determined.

Computational modelling for the spiral flow in umbilical arteries with different systole/diastole flow velocity ratios

The systole/diastole (S/D) flow velocity ratios in umbilical arteries (UAs) have been used to assess the health status of the feto-placental circulation, yet its connection to the morphology of UAs, specifically its coiling pattern remains unclear. Spiral flow induces unbalanced wall shear stress (WSS) distribution in UAs, and may contribute to the uneven arterial wall thickness, and the chirality. In this paper, we use a 3D computational fluid dynamics (CFD) technique to quantify the wall shear stress (WSS) in UA models of two configurations, i.e. at 0.17 and 0.50 spirals per centimeter, to represent normo- and hyper-coiling, respectively. For CFD simulations we use two different S/D ratios (3.02 and 5.70) revealed from the ultrasonography waveforms of a normal and an intrauterine growth restriction (IUGR) case. We found that more coils in the UA model enhanced WSS throughout a cardiac cycle (up to 24%) with the same inflow condition. In addition, time-averaged WSS are generally increased and more uneven in the hyper-coiling model. We suggest that the large WSS difference between the peak systole and end diastole (62% higher in the IURG case than the normal case) may induce uneven stenosis distribution at UAs, and contribute to UA chirality.

Quality assessment of fetal middle cerebral and umbilical artery Doppler images using an objective scale within an international randomized controlled trial

OBJECTIVES

To determine the quality of Doppler images of the fetal middle cerebral artery (MCA) and umbilical artery (UA) using an objective scale, and to determine the reliability of this scale, within a multicenter randomized controlled trial (Revealed versus concealed criteria for placental insufficiency in unselected obstetric population in late pregnancy (Ratio37)).

METHODS

The Ratio37 trial is an ongoing randomized, open-label, multicenter controlled study of women with a low-risk pregnancy recruited at 20 weeks. Doppler measurements of the fetal MCA and UA were performed at 37 weeks. Twenty patients from each of the six participating centers were selected randomly, with two images evaluated per patient (one each for the MCA and UA). The quality of a total of 240 images was evaluated by six experts, scored on an objective scale of six items. Inter- and intrarater reliability was assessed using the Fleiss-modified kappa statistic for ordinal scales.

RESULTS

On average, 89.2% of MCA images and 85.0% of UA images were rated as being of perfect (score of 6) or almost perfect (score of 5) quality. Kappa values for intrarater reliability of quality assessment were 0.90 (95% CI, 0.88-0.92) and 0.90 (95% CI, 0.88-0.93) for the MCA and UA, respectively. The corresponding inter-rater reliability values were 0.85 (95% CI, 0.81-0.89) and 0.84 (95% CI, 0.80-0.89), respectively.

CONCLUSION

The quality of MCA and UA Doppler ultrasound images can be evaluated reliably using an objective scale. Over 85% of images, which were obtained by operators from a broad range of clinical practices within a multicenter study, were rated as being of perfect or almost perfect quality. Intra- and inter-rater reliability of quality assessment was very good. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Preeclampsia: Risk Factors, Diagnosis, Management, and the Cardiovascular Impact on the Offspring

Hypertensive disorders of pregnancy affect up to 10% of pregnancies worldwide, which includes the 3%–5% of all pregnancies complicated by preeclampsia. Preeclampsia is defined as new onset hypertension after 20 weeks’ gestation with evidence of maternal organ or uteroplacental dysfunction or proteinuria. Despite its prevalence, the risk factors that have been identified lack accuracy in predicting its onset and preventative therapies only moderately reduce a woman’s risk of preeclampsia. Preeclampsia is a major cause of maternal morbidity and is associated with adverse foetal outcomes including intra-uterine growth restriction, preterm birth, placental abruption, foetal distress, and foetal death in utero. At present, national guidelines for foetal surveillance in preeclamptic pregnancies are inconsistent, due to a lack of evidence detailing the most appropriate assessment modalities as well as the timing and frequency at which assessments should be conducted. Current management of the foetus in preeclampsia involves timely delivery and prevention of adverse effects of prematurity with antenatal corticosteroids and/or magnesium sulphate depending on gestation. Alongside the risks to the foetus during pregnancy, there is also growing evidence that preeclampsia has long-term adverse effects on the offspring. In particular, preeclampsia has been associated with cardiovascular sequelae in the offspring including hypertension and altered vascular function.

Reflected hemodynamic waves influence the pattern of Doppler ultrasound waveforms along the umbilical arteries

The pulsatile pattern of blood motion measured by Doppler ultrasound within the umbilical artery is known to contain useful diagnostic information and is widely used to monitor pregnancies at risk of fetal growth restriction or stillbirth. Animal studies have identified reflected pressure waves traveling counter to the direction of blood flow as an important factor in the shape of these waveforms. In the present study, we establish a method to measure reflected waves in the human umbilical artery and assess their influence on blood velocity pulsation. Ninety-five pregnant women were recruited from a general obstetrics clinic between 26 and 37 wk of gestation and examined by Doppler ultrasound. Blood velocity waveforms were recorded for each umbilical artery at three locations along the umbilical cord. With the use of a computational procedure, a pair of forward and reverse propagating waves was identified to explain the variation in observed Doppler ultrasound waveforms along the cord. Among the data sets that met data quality requirements, waveforms in 93 of the 130 arteries examined agreed with the wave reflection model to within 1.5% and showed reflections ranging in magnitude from 3 to 52% of the forward wave amplitude. Strong reflections were associated with large differences in pulsatility between the fetal and placental ends of the cord. As reflections arise from transitions in the biomechanical properties of blood vessels, these observations provide a plausible mechanism for the link between abnormal waveforms and clinically significant placental pathology and could lead to more precise screening methods for detecting pregnancies complicated by placental disease. NEW & NOTEWORTHY The pulsatile pattern of blood motion measured by Doppler ultrasound within the umbilical artery is known to contain useful diagnostic information and is widely used to monitor pregnancies at risk of fetal growth restriction. We demonstrate based on a study of 95 pregnant women that the shape of these umbilical artery waveforms is explained by the presence of a reflected pressure wave traveling counter to the direction of blood flow.

Image-scoring system for umbilical and uterine artery pulsed-wave Doppler ultrasound measurement

OBJECTIVES

To develop an objective image-scoring system for pulsed-wave Doppler measurement of maternal uterine and fetal umbilical arteries, and evaluate how this compares with subjective assessment.

METHODS

As an extension to the INTERGROWTH-21^st Project, we developed a scoring system based on six predefined criteria for uterine and umbilical artery pulsed-wave Doppler measurements. Objective evaluation using the scoring system was compared with subjective assessment which consisted of classifying an image as simply acceptable or unacceptable. Based on sample size estimation, a total of 120 umbilical and uterine artery Doppler images were selected randomly from the INTERGROWTH-21^st image database. Two independent reviewers evaluated all images in a blinded fashion, both subjectively and using the six-point scoring system. Percentage agreement and kappa statistic were compared between the two methods.

RESULTS

The overall agreement between reviewers was higher for objective assessment using the scoring system (agreement, 85%; adjusted kappa, 0.70) than for subjective assessment (agreement, 70%; adjusted kappa, 0.47). For the six components of the scoring system, the level of agreement (adjusted kappa) was 0.97 for anatomical site, 0.88 for sweep speed, 0.77 for magnification, 0.68 for velocity scale, 0.68 for image clarity and 0.65 for angle of insonation.

CONCLUSION

In quality assessment of umbilical and uterine artery pulsed-wave Doppler measurements, our proposed objective six-point image-scoring system is associated with greater reproducibility than is subjective assessment. We recommend this as the preferred method for quality control, auditing and teaching. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cardiotocography and beyond: a review of one-dimensional Doppler ultrasound application in fetal monitoring

One-dimensional Doppler ultrasound (1D-DUS) provides a low-cost and simple method for acquiring a rich signal for use in cardiovascular screening. However, despite the use of 1D-DUS in cardiotocography (CTG) for decades, there are still challenges that limit the effectiveness of its users in reducing fetal and neonatal morbidities and mortalities. This is partly due to the noisy, transient, complex and nonstationary nature of the 1D-DUS signals. Current challenges also include lack of efficient signal quality metrics, insufficient signal processing techniques for extraction of fetal heart rate and other vital parameters with adequate temporal resolution, and lack of appropriate clinical decision support for CTG and Doppler interpretation. Moreover, the almost complete lack of open research in both hardware and software in this field, as well as commercial pressures to market the much more expensive and difficult to use Doppler imaging devices, has hampered innovation. This paper reviews the basics of fetal cardiac function, 1D-DUS signal generation and processing, its application in fetal monitoring and assessment of fetal development and wellbeing. It also provides recommendations for future development of signal processing and modeling approaches, to improve the application of 1D-DUS in fetal monitoring, as well as the need for annotated open databases.

Three-Dimensional Power Doppler Evaluation of Cerebral Vascular Blood Flow: A Novel Tool in the Assessment of Fetal Growth Restriction

OBJECTIVES

To determine whether fetuses with fetal growth restriction (FGR) are more likely to have abnormal cerebral vascular flow patterns compared to fetuses who are appropriate for gestational age (AGA) when quantified by using 3-dimensional (3D) power Doppler ultrasound.

METHODS

We conducted a prospective cohort study of singleton gestations presenting for growth ultrasound examination between 24 and 36 weeks' gestation. Patients with FGR (estimated fetal weight < 10th percentile) were enrolled and matched 1:1 for gestational age (±7 days) with AGA fetuses. A standardized 3D power Doppler image of the middle cerebral artery territory was obtained from each patient. The vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) were calculated by the Virtual Organ computer-aided analysis technique (GE Healthcare, Milwaukee, WI). These indices were compared between FGR and AGA fetuses and correlated with 2-dimensional Doppler parameters. Neonatal outcomes were also compared with respect to the 3D parameters.

RESULTS

Of 306 patients, there were 151 cases of FGR. There was no difference in the VI (6.0 versus 5.7; P = .65) or VFI (2.0 versus 1.8; P = .31) between the groups; however, the FI was significantly higher in FGR fetuses compared to AGA controls (33.9 versus 32.3; P = .009). There was a weak, but significant, negative correlation between the FI and both the middle cerebral artery pulsatility index (r = -0.34; P < .001) and cerebroplacental ratio (r = -0.29; P < .001). Within the FGR group, there was no difference in any of the 3D vascular indices with regard to neonatal outcomes.

CONCLUSIONS

Three-dimensional power Doppler measurement of cerebral blood flow, but not the vascularization pattern, is significantly altered in FGR. This measurement may play a future role in distinguishing pathologic FGR from constitutionally small growth.

Performance of third-trimester combined screening model for prediction of adverse perinatal outcome

OBJECTIVE

To explore the potential value of third-trimester combined screening for the prediction of adverse perinatal outcome (APO) in the general population and among small-for-gestational-age (SGA) fetuses.

METHODS

This was a nested case-control study within a prospective cohort of 1590 singleton gestations undergoing third-trimester evaluation (32 + 0 to 36 + 6 weeks' gestation). Maternal baseline characteristics, mean arterial blood pressure, fetoplacental ultrasound and circulating biochemical markers (placental growth factor (PlGF), lipocalin-2, unconjugated estriol and inhibin A) were assessed in all women who subsequently had an APO (n = 148) and in a control group without perinatal complications (n = 902). APO was defined as the occurrence of stillbirth, umbilical artery cord blood pH < 7.15, 5-min Apgar score < 7 or emergency operative delivery for fetal distress. Logistic regression models were developed for the prediction of APO in the general population and among SGA cases (defined as customized birth weight < 10^th centile).

RESULTS

The prevalence of APO was 9.3% in the general population and 27.4% among SGA cases. In the general population, a combined screening model including a-priori risk (maternal characteristics), estimated fetal weight (EFW) centile, umbilical artery pulsatility index (UA-PI), estriol and PlGF achieved a detection rate for APO of 26% (area under receiver-operating characteristics curve (AUC), 0.59 (95% CI, 0.54-0.65)), at a 10% false-positive rate (FPR). Among SGA cases, a model including a-priori risk, EFW centile, UA-PI, cerebroplacental ratio, estriol and PlGF predicted 62% of APO (AUC, 0.86 (95% CI, 0.80-0.92)) at a FPR of 10%.

CONCLUSIONS

The use of fetal ultrasound and maternal biochemical markers at 32-36 weeks provides a poor prediction of APO in the general population. Although it remains limited, the performance of the screening model is improved when applied to fetuses with suboptimal fetal growth. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

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.

An integrated approach to fetal growth restriction

Fetal growth restriction (FGR) is among the most common complications of pregnancy. FGR is associated with placental insufficiency and poor perinatal outcomes. Clinical management is challenging because of variability in clinical presentation. Fetal smallness (estimated fetal weight <10th centile for gestational age) remains the best clinical surrogate for FGR. However, it is commonly accepted that not all forms of fetal smallness represent true FGR. In a significant subset of small fetuses, there is no evidence of placental involvement, perinatal outcomes are nearly normal, and they are clinically referred to as "only" small for gestational age (SGA). Doppler may improve the clinical management of FGR; however, the need to use several parameters sometimes results in a number of combinations that may render interpretation challenging when translating into clinical decisions. We propose that the management of FGR can be simplified using a sequential approach based on three steps: (1) identification of the "small fetus," (2) differentiation between FGR and SGA, and (3) timing of delivery according to a protocol based on stages of fetal deterioration.

Normogram of umbilical artery Doppler indices in singleton pregnancies in south-western Nigerian women

AIM

To determine the Doppler indices of the umbilical arteries in normal singleton pregnancy with a view to generating local reference ranges.

METHODS

In this prospective, cross-sectional study, 400 pregnant women at 15-39 weeks' gestational age, with estimated fetal weight within the 10th and 90th percentile, no fetal malformation(s), and without any history of maternal medical disease, were recruited. Umbilical arteries were assessed on ultrasound, with the subjects in the supine position. Resistivity index (RI), pulsatility index (PI) and systolic/diastolic (S/D) ratio were recorded and analyzed.

RESULTS

All the umbilical arteries were paired; no single umbilical artery was seen. Mean RI, PI, and S/D ratio declined with gestational age, and decreased from 1.265 to 0.829, from 0.760 to 0.585 and from 4.068 to 2.365, respectively, from 15 to 39 weeks of gestation. With regard to correlation between gestational age and Doppler indices, r = - 0.598 for PI (P < 0.05), - 0.437 for RI (P < 0.05), and - 0.538 for S/D ratio (P < 0.05). Decline in the Doppler indices was progressive with gestational age.

CONCLUSION

A normogram of umbilical artery Doppler indices was constructed, which showed that the indices decreased with gestational age. These normative data could serve as reference ranges for evaluation of the umbilical artery circulation in this locality.

Semi-parametric estimation of random effects in a logistic regression model using conditional inference

This paper describes a new approach to the estimation in a logistic regression model with two crossed random effects where special interest is in estimating the variance of one of the effects while not making distributional assumptions about the other effect. A composite likelihood is studied. For each term in the composite likelihood, a conditional likelihood is used that eliminates the influence of the random effects, which results in a composite conditional likelihood consisting of only one-dimensional integrals that may be solved numerically. Good properties of the resulting estimator are described in a small simulation study.

Potential role of folate in pre-eclampsia

Dietary deficiencies of folate and other B vitamin cofactors involved in one-carbon metabolism, together with genetic polymorphisms in key folate-methionine metabolic pathway enzymes, are associated with increases in circulating plasma homocysteine, reduction in DNA methylation patterns, and genome instability events. All of these biomarkers have also been associated with pre-eclampsia. The aim of this review was to explore the literature and identify potential knowledge gaps in relation to the role of folate at the genomic level in either the etiology or the prevention of pre-eclampsia. A systematic search strategy was designed to identify citations in electronic databases for the following terms: folic acid supplementation AND pre-eclampsia, folic acid supplementation AND genome stability, folate AND genome stability AND pre-eclampsia, folic acid supplementation AND DNA methylation, and folate AND DNA methylation AND pre-eclampsia. Forty-three articles were selected according to predefined selection criteria. The studies included in the present review were not homogeneous, which made pooled analysis of the data very difficult. The present review highlights associations between folate deficiency and certain biomarkers observed in various tissues of women at risk of pre-eclampsia. Further investigation is required to understand the role of folate in either the etiology or the prevention of pre-eclampsia.

Diagnosis and Treatment of Hypertensive Pregnancy Disorders. Guideline of DGGG (S1-Level, AWMF Registry No. 015/018, December 2013)

Purpose: Official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG). Hypertensive pregnancy disorders contribute significantly to perinatal as well as maternal morbidity and mortality worldwide. Also in Germany these diseases are a major course for hospitalization during pregnancy, iatrogenic preterm birth and long-term cardiovascular morbidity. Methods: This S1-guideline is the work of an interdisciplinary group of experts from a range of different professions who were commissioned by DGGG to carry out a systematic literature search of positioning injuries. Members of the participating scientific societies develop a consensus in an informal procedure. Afterwards the directorate of the scientific society approves the consensus. Recommendations: This guideline summarizes the state-of-art for classification, risk stratification, diagnostic, treatment of hypertensive pregnancy disorders.

Antenatal tests of fetal wellbeing

In current obstetric practice, there is frequently a need to assess fetal wellbeing. This is particularly so in those fetuses at risk, including the small-for-gestational-age fetus or the fetus of a mother who presents with reduced fetal movements or who has an obstetric complication such as pre-eclampsia. It is important that the clinician is able to assess fetal wellbeing in such cases, especially in preterm gestations, when inappropriate delivery could have serious adverse consequences. In this paper, we review the current evidence for the use and the limitations of widely used methods of antenatal monitoring including the use of cardiotocography, biophysical profile, and ultrasound-derived parameters including umbilical artery, middle cerebral artery, and ductus venosus Doppler flow.

Uterine and umbilical artery Doppler at 28 weeks for predicting adverse pregnancy outcomes in women with abnormal uterine artery Doppler findings in the early second trimester

OBJECTIVE

The objective of this study was to determine the contribution of uterine (UtA) and umbilical arteries (UA) Doppler examination at 28 weeks to predict adverse pregnancy outcomes in women who had increased resistance in UtA in the early second trimester.

METHODS

Women with UtA mean pulsatility index (PI) above the 95th centile at 19-22 weeks of gestation were offered a growth scan including Doppler examination of UtA and UA at 28 weeks. Adverse pregnancy outcomes included small for gestational age (SGA), defined as birth weight below the tenth centile, preeclampsia (PE) and early-onset PE (PE before 34 weeks).

RESULTS

We studied 266 pregnant women with elevated PI in the UtAs in the second trimester and ultrasound reassessment at 28 weeks. UtA PI >95th centile at 28 weeks was associated with subsequent PE [odds ratio (OR): 10.0, 95% CI: 2.3-43.5], early-onset PE (OR: 57.7, 95% CI: 3.8-87.6) and SGA less than the tenth centile (OR: 5.5, 2.2-13.9). UA PI >95th centile at 28 weeks was not significantly associated with any adverse outcome.

CONCLUSIONS

In women with abnormal UtA Doppler in the early second trimester scan, persistence of elevated UtA PI, but not abnormal UA PI, is associated with adverse pregnancy outcomes including PE, early-onset PE and SGA. © 2014 John Wiley & Sons, Ltd.

Audio spectrum analysis of umbilical artery Doppler ultrasound signals applied to a clinical material

Analysis of umbilical artery flow velocity waveforms characterized by pulsatility index (PI) is used to evaluate fetoplacental circulation in high-risk pregnancies. However, an experienced sonographer may be able to further differentiate between various timbres of Doppler audio signals. Recently, we have developed a method for objective audio signal characterization; the method has been tested in an animal model. In the present pilot study, the method was for the first time applied to human pregnancies. Doppler umbilical artery velocimetry was performed in 13 preterm fetuses before and after two doses of 12 mg betamethasone. The auditory measure defined by the frequency band where the spectral energy had dropped 15 dB from its maximum level (MAXpeak-15 dB ), increased two days after betamethasone administration (p = 0.001) parallel with a less pronounced decrease in PI (p = 0.04). The new auditory parameter MAXpeak-15 dB reflected the changes more sensitively than the PI did.

Umbilical artery Doppler at 19 to 22 weeks of gestation in the prediction of adverse pregnancy outcomes

OBJECTIVE

The aim of this study was to determine the clinical utility of Doppler assessment of the umbilical artery in the second trimester scan for predicting adverse pregnancy outcomes.

METHODS

Singleton pregnancies that had undergone routine anomaly scan at 19 to 22 weeks of gestation with umbilical and uterine artery Doppler measurements. Receiver operating characteristic curves were constructed to evaluate the ability of umbilical artery pulsatility index (PI) to predict small for gestational age and preeclampsia.

RESULTS

The final study population comprised 4565 singleton pregnancies. Multiple regression analysis showed significant independent contribution of umbilical artery PI in predicting SGA <10th and SGA <5th centiles (adjusted odds ratios of 2.51 and 3.51, respectively). By using a cutoff of umbilical artery PI >90th centile, the likelihood ratio of SGA <5th centile is 2.3 (95% CI: 1.7-3.0).

CONCLUSIONS

Umbilical artery PI at 19 to 22 weeks of gestation is significantly associated with SGA below the tenth and fifth centiles. A multivariate model combining umbilical and uterine artery Doppler measurements with additional maternal and sonographic characteristics may help predict small for gestational age, particularly those below the fifth centile.

Doppler ultrasound evaluation in preeclampsia

Background

Worldwide preeclampsia (PE) is the leading cause of maternal death and affects 5 to 8% of pregnant women. PE is characterized by elevated blood pressure and proteinuria. Doppler Ultrasound (US) evaluation has been considered a useful method for prediction of PE; however, there is no complete data about the most frequently altered US parameters in the pathology. The aim of this study was to evaluate the uterine, umbilical, and the middle cerebral arteries using Doppler US parameters [resistance index (RI), pulsatility index (PI), notch (N), systolic peak (SP) and their combinations] in pregnant women, in order to make a global evaluation of hemodynamic repercussion caused by the established PE.

Results

A total of 102 pregnant Mexican women (65 PE women and 37 normotensive women) were recruited in a cases and controls study. Blood velocity waveforms from uterine, umbilical, and middle cerebral arteries, in pregnancies from 24 to 37 weeks of gestation were recorded by trans-abdominal examination with a Toshiba Ultrasound Power Vision 6000 SSA-370A, with a 3.5 MHz convex transducer. Abnormal general Doppler US profile showed a positive association with PE [odds ratio (OR) = 2.93, 95% confidence interval (CI) = 1.2 - 7.3, P = 0.021)], and a specificity and predictive positive value of 89.2% and 88.6%, respectively. Other parameters like N presence, RI and PI of umbilical artery, as well as the PI of middle cerebral artery, showed differences between groups (P values < 0.05).

Conclusion

General Doppler US result, as well as N from uterine vessel, RI from umbilical artery, and PI from umbilical and middle cerebral arteries in their individual form, may be considered as tools to determine hemodynamic repercussion caused by PE.

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.

Which intrauterine growth restricted fetuses at term benefit from early labour induction? A secondary analysis of the DIGITAT randomised trial

OBJECTIVE

The Disproportionate Intrauterine Growth Intervention Trial at Term (DIGITAT trial) showed that in women with suspected intrauterine growth restriction (IUGR) at term, there were no substantial outcome differences between induction of labour and expectant monitoring. The objective of the present analysis is to evaluate whether maternal or fetal markers could identify IUGR fetuses who would benefit from early labour induction.

STUDY DESIGN

The DIGITAT trial was a multicenter, parallel and open-label randomised controlled trial in women who had a singleton pregnancy beyond 36+0 weeks' gestation with suspected IUGR (n=650). Women had been randomly allocated to either labour induction or expectant monitoring. The primary outcome was a composite measure of adverse neonatal outcome, defined as neonatal death before hospital discharge, Apgar score <7, umbilical artery pH <7.05, or admission to neonatal intensive care. Using logistic regression modelling, we investigated associations between outcome and 17 markers, maternal characteristics and fetal sonographic and Doppler velocimetry measurements, all collected at study entry.

RESULTS

17 (5.3%) infants in the induction group had an adverse neonatal outcome compared to 20 (6.1%) in the expectant monitoring group. The only potentially informative marker for inducing labour was maternal pre-pregnancy body mass index (BMI). Otherwise, we observed at best weak associations between a benefit from labour induction and maternal age, ethnicity, smoking, parity, pregnancy-induced hypertension or preeclampsia, Bishop score and gestational age, or fetal sonographic markers (gender, estimated fetal weight, body measurements, oligohydramnios, or umbilical artery pulsatility index and end diastolic flow).

CONCLUSION

In late preterm and term pregnancies complicated by suspected intrauterine growth restriction, most of the known prognostic markers seem unlikely to be helpful in identifying women who could benefit from labour induction, except for maternal pre-pregnancy BMI.

Yoga for high-risk pregnancy: a randomized controlled trial

Background:

Improvements in technology have increased the chances of survival for the micro-premature infant and the very low birth-weight infant but have significantly increased the financial burden of health care organizations. This economic burden has a significant impact on third-party payers and on society in general.

Aim:

The study was designed to assess yoga therapy (YT) module on maternal stress level in high risk pregnancy.

Subjects and Methods:

In the present study, sixty-eight pregnant women (38 in the control group with standard antenatal care and 30 in the YT group) with 27.2 (5.2) years of mean age recruited from the outpatient services of medical college and hospital in Bangalore, South India, were participated. The study was a single-blind randomized controlled clinical trial. Perceived stress scale (PSS) was measured during the 12^th, 20^th, and 28^th weeks of pregnancy. SPSS version 16.0 (Chicago, IL, USA) was used for all data analysis. When the data were found to be normally distributed, the RMANOVA were used to assess the PSS scores between the yoga and control groups. Significant values were set at P < 0.05.

Results:

There was a significant difference in the PSS level of the YT group with significantly reduced scores at the second follow-up (28^th week of pregnancy) compared to the control group (P = 0.02). Women who took part in the YT module reported significantly fewer pregnancy discomforts decrease in PSS (P = 0.02) than the control group where the stress level was increased (RMANOVA test using SPSS-16).

Conclusion:

The present study suggests that the YT module can decrease the stress level during high-risk pregnancy complications. Thus, practicing YT during high-risk pregnancy is not only a cost-effective option but also a feasible and safe option. Additional well-designed studies are needed before a strong recommendation can be made.

Elevated umbilical artery systolic/diastolic ratio in the absence of fetal growth restriction

PURPOSE

To evaluate whether patients with isolated elevation of umbilical artery (UA) systolic/diastolic (S/D) ratio are at increased risk for adverse perinatal outcome.

METHODS

This is a retrospective cohort study of 330 patients who underwent routine evaluation at our maternal fetal medicine center. We regularly perform UA S/D ratio analysis with every third trimester sonogram. All identified patients were included and divided into four groups based on estimated fetal weight (EFW) and UA S/D ratio. Perinatal outcome was compared between the groups.

RESULTS

Regardless of the EFW, fetuses with persistent elevated UA S/D ratio showed significantly more preterm deliveries (p < .001), neonatal intensive care unit (NICU) admissions (p < .001), longer stay in the NICU (p < .001) and lower birth weight (p < .001) relative to controls. Stepwise logistic regression analysis demonstrated that being a member in any study group significantly and independently predicted birth weight less than the 10th percentile and preterm delivery. Patients with persistently elevated S/D ratio were significantly and independently from other factors, more likely to have a newborn admitted to the NICU.

CONCLUSION

Our results indicate a suboptimal perinatal outcome in all pregnancies with an elevated UA S/D ratio. These fetuses may benefit from intensive monitoring.

Umbilical venous blood flow and its measurement in the human fetus

In this review, we evaluate the published methodologies to describe a noninvasive technique for the quantitative assessment of umbilical venous blood flow in the human fetus. We identify a number of variations in the reported methodologies and address some of the common errors associated with Doppler assessment of umbilical venous flow volume. The potential role of umbilical venous flow volumetry in the management of intrauterine growth restriction is briefly evaluated including its utility and reliability in everyday clinical practice.

Pre-eclampsia, severe pre-eclampsia and hemolysis, elevated liver enzymes and low platelets syndrome: what is new?

Pre-eclampsia and eclampsia have been known to us for centuries. Significant improvements have been made in our knowledge of the disease, however, delivery remains the only effective form of treatment. There is widespread variation of practice in the management of hypertensive disease in pregnancy, which may lead to substandard care. The use of aspirin in preventing pre-eclampsia, the lack of correlation between urinary protein and adverse outcome, and the ineffectiveness of corticosteroids in the management of hemolysis and elevated liver enzymes and low platelets syndrome are a few of the developments that will alter the way this condition is managed. This article aims to provide a general overview of pre-eclampsia, eclampsia and hemolysis, hemolysis and elevated liver enzymes and low platelets syndrome supported by the latest evidence, which will help the care provider adopt a focused approach and use the latest knowledge to understand and manage this old condition.

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%.

Evidence-based approach to umbilical artery Doppler fetal surveillance in high-risk pregnancies: an update

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 and preeclampsia. Moreover, randomized clinical trials and their meta-analyses have shown its effectiveness in decreasing perinatal mortality (level I evidence). This is the only antepartum fetal test that has shown this level of effectiveness. There is no evidence that routine Doppler in low-risk pregnancies improves the outcome. It is recommended that umbilical artery Doppler should be the standard of practice in managing high-risk pregnancies complicated with fetal growth restriction and preeclampsia (level A recommendation). However, its use should be integrated with other current fetal monitoring tests (levels B and C recommendation). The overall management should also be guided by additional clinical considerations such as the gestational age, fetal and maternal status, and obstetrical conditions.

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).

Observer agreement of lower limb venous reflux assessed by duplex ultrasound scanning using manual and pneumatic cuff compression in patients with chronic venous disease and controls

OBJECTIVES

The study aimed to evaluate observer agreement between two experienced ultrasound operators examining deep venous reflux assessed by duplex ultrasound (DU) using either manual or pneumatic cuff compression. In addition, the two methods were compared with each other with regard to immediate "eyeballing" and direct measurements of reflux time from Doppler flow curves.

DESIGN

This was a case control study.

MATERIAL AND METHODS

Cases were found among patients admitted to our department with deep venous thrombosis of the iliac, femoral or popliteal veins during the period 1999-2006. Controls were departmental staff. DU was used to assess valve function in the common femoral, femoral and popliteal veins in the standing position using manual and pneumatic cuff compression. The investigators were blinded to the other's observations. Observer agreement was assessed using the Rasch model for binary items.

RESULTS

Twenty patients and 20 controls participated in the study and were analysed by the Rasch model. Quantitative measurement was found to be more reliable than "eyeballing", and cuff compression was more reproducible in identifying reflux than manual compression. We found that assessment by manual measurement by one investigator functioned at a lower level of expertise than for the other investigator.

CONCLUSIONS

Cuff measurements were more accurate in diagnosing deep venous reflux than manual measurements, and measurement was more accurate than "eyeballing". The fact that assessment by manual compression by one investigator functioned at a lower level of expertise suggests that cuff measurement might be the optimal assessment method, especially in the difficult cases.

Fetal umbilical artery Doppler to predict compromise of fetal/neonatal wellbeing in a high-risk population: systematic review and bivariate meta-analysis

OBJECTIVE

We investigated the accuracy of fetal umbilical artery Doppler to predict the risk of compromise of fetal/neonatal wellbeing in a high-risk population.

METHODS

Searches in MEDLINE, Embase, The Cochrane Library and Medion (from inception to March 2009) were carried out, together with hand searching of relevant journals, reference list checking of included articles and contact with experts. Criteria for selection were observational studies with umbilical artery Doppler used in a high-risk pregnant population with an outcome measure for compromise of fetal/neonatal wellbeing. Data on study design, quality and results were extracted to construct 2 × 2 tables. Bivariate meta-analysis was performed. Likelihood ratios (LRs) were used as the summary measure of accuracy.

RESULTS

One-hundred and four studies met the selection criteria (19 191 fetuses). In a high-risk population, umbilical artery Doppler predicted small-for-gestational age with a pooled LR+ of 3.76 (2.96, 4.76) and pooled LR- of 0.52 (0.45, 0.61), and compromise of fetal/neonatal wellbeing with a pooled LR+ of 3.41 (2.68, 4.34) and pooled LR- of 0.55 (0.48, 0.62). In this group it was also possible to predict, with accuracy, intrauterine death (pooled LR+ = 4.37 (0.88, 21.8); pooled LR- = 0.25 (0.07, 0.91)) and acidosis (pooled LR+ = 2.75 (1.48, 5.11); pooled LR- = 0.58 (0.36, 0.94)).

CONCLUSIONS

In a high-risk population, fetal umbilical artery Doppler is a moderately useful test with which to predict mortality and risk of compromise.

Diagnosis and management of fetal growth restriction

Fetal growth restriction (FGR) remains a leading contributor to perinatal mortality and morbidity and metabolic syndrome in later life. Recent advances in ultrasound and Doppler have elucidated several mechanisms in the evolution of the disease. However, consistent classification and characterization regarding the severity of FGR is lacking. There is no cure, and management is reliant on a structured antenatal surveillance program with timely intervention. Hitherto, the time to deliver is an enigma. In this paper, the challenges in the diagnosis and management of FGR are discussed. The biophysical profile, Doppler, biochemical and molecular technologies that may refine management are reviewed. Finally, a model pathway for the clinical management of pregnancies complicated by FGR is presented.

Assessing and quantifying inter-rater variation for dichotomous ratings using a Rasch model

We present a new model-based approach to the analysis of agreement between raters in a situation where all raters have supplied dichotomous ratings of the same cases in a sample. The model is a logistic regression model with random effects – a Rasch model. In the rater setting, the Rasch model includes parameters that allow raters to have different propensities to score a given set of individuals positively or negatively – the rater bias. An exact score test of the hypothesis of no rater bias is proposed and is shown to be an exact generalised McNemar's test. Based on the model, we suggest quantifying the rater variation as a suitable measure of the variation of the rater odds ratios. An important example that will serve to motivate and illustrate the proposed model, is the study of Umbilical artery Doppler velocimetry used by obstetricians to assess the status of a foetus. The purpose of the assessment is to improve the foetus' chance of survival by choosing the optimal time of elective delivery. In the study, data related to 139 perinatal deaths were sent to 32 experts who were asked whether the use of Doppler velocimetry might have prevented each death.

[Obstetrical care in gestational diabetes and management of preterm labor]

OBJECTIVES

Search for data necessary to elaborate recommendations for obstetrical care in gestational diabetes and management of preterm labor.

METHODS

Systematic review of the literature and levels of evidence.

RESULTS

In case of gestational diabetes and in the absence of disease or other risk factor associated, there is no evidence to support a systematic rate of clinical follow up different from other pregnancy. The relevance of ultrasound estimates of fetal weight is limited. No formula is superior to others or to the simple measurement of abdominal circumference for the prediction of macrosomia (EL3). The usefulness of the research septal hypertrophy is not demonstrated (EL4). The systematic application of umbilical Doppler has no proven benefits in the absence of growth restriction or hypertension associated (EL4). Monthly ultrasound monitoring of the fetus can be proposed for diabetics on insulin or poorly controlled. In cases of gestational diabetes controlled by diet, cardiotocography of fetal heart rate has not proven useful. In poorly controlled diabetes and/or on insulin, the registration may be discussed taking into account other risk factors associated (EL4). A weekly recording of fetal heart rate is often recommended in case of type 2 diabetes discovered during pregnancy. In case of preterm labor, calcium channel blockers and oxytocin antagonists can be used without specific precautions. The risk of using beta-adrenergic outweighs the benefit. Administration of corticosteroid can be done under glycemic control, with insulin therapy if necessary. Screening test for gestational diabetes should not be performed within few days after last steroid injection.

Uterine and umbilical artery Doppler velocimetry as a predictor for adverse pregnancy outcomes in pregnant women with anemia

AIMS

The aim of this study was to investigate the significance of Doppler ultrasound as a predictor for adverse pregnancy outcomes in Korean women with anemia during the third trimester of pregnancy.

METHODS

A retrospective study comparing women with (n=377) and without (n=3183) anemia was performed. Maternal anemia was defined as hemoglobin concentration <10 g/dL. Umbilical artery Doppler (UmA) and uterine artery Doppler (UtA) velocimetry was performed before delivery.

RESULTS

There were higher rates of small for gestational age, cesareans for fetal distress, and preterm birth among the anemic compared to non-anemic women. When maternal anemia was combined with abnormal Doppler, the odds ratio (OR) of adverse pregnancy outcome was further increased. Both abnormal UtA and UmA to predict adverse pregnancy outcome showed sensitivity, specificity, positive and negative predictive values of 41.2%, 97.4%, 85.9%, and 51.2%, respectively (OR 2.0; 95% confidence interval 1.2-2.3).

CONCLUSIONS

Doppler ultrasound examination could be used as a predictor for adverse pregnancy outcomes in women with anemia during the third trimester.

Defining normal and abnormal fetal growth: promises and challenges

Normal fetal growth is a critical component of a healthy pregnancy and influences the long-term health of the offspring. However, defining normal and abnormal fetal growth has been a long-standing challenge in clinical practice and research. We review various references and standards that are used widely to evaluate fetal growth and discuss common pitfalls of current definitions of abnormal fetal growth. Pros and cons of different approaches to customize fetal growth standards are described. We further discuss recent advances toward an integrated definition for fetal growth restriction. Such a definition may incorporate fetal size with the status of placental health that is measured by maternal and fetal Doppler velocimetry and biomarkers, biophysical findings, and genetics. Although the concept of an integrated definition appears promising, further development and testing are required. An improved definition of abnormal fetal growth should benefit both research and clinical practice.