Doppler assessment of the aortic isthmus and perinatal outcome in preterm fetuses with severe intrauterine growth restriction

Association between Doppler assessment and secondary cesarean delivery for intrapartum fetal compromise in small-for-gestational-age fetuses

PURPOSE

To elucidate the association between arterial and venous Doppler ultrasound parameters and the risk of secondary cesarean delivery for intrapartum fetal compromise (IFC) and neonatal acidosis in small-for-gestational-age (SGA) fetuses.

METHODS

This single-center, prospective, blinded, cohort study included singleton pregnancies with an estimated fetal weight (EFW) < 10th centile above 36 gestational weeks. Upon study inclusion, all women underwent Doppler ultrasound, including umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, fetal aortic isthmus (AoI) PI, umbilical vein blood flow (UVBF), and modified myocardial performance index (mod-MPI). Primary outcome was defined as secondary cesarean section due to IFC.

RESULTS

In total, 87 SGA pregnancies were included, 16% of which required a cesarean section for IFC. Those fetuses revealed lower UVBF corrected for abdominal circumference (AC) (5.2 (4.5-6.3) vs 7.2 (5.5-8.3), p = 0.001). There was no difference when comparing AoI PI, UA PI, ACM PI, or mod-MPI. No association was found for neonatal acidosis. After multivariate logistic regression, UVBF/AC remained independently associated with cesarean section due to IFC (aOR 0.61 [0.37; 0.91], p = 0.03) and yielded an area under the curve (AUC) of 0.78 (95% CI, 0.67-0.89). A cut-off value set at the 50th centile of UVBF/AC reached a sensitivity of 86% and specificity of 58% for the occurrence of cesarean section due to IFC (OR 8.1; 95% CI, 1.7-37.8, p = 0.003).

CONCLUSION

Low levels of umbilical vein blood flow (UVBF/AC) were associated with an increased risk among SGA fetuses to be delivered by cesarean section for IFC.

Fetal aortic isthmus Doppler assessment to predict the adverse perinatal outcomes associated with fetal growth restriction: systematic review and meta-analysis

PURPOSE

Fetal growth restriction (FGR) management and delivery planning is based on a multimodal approach. This meta-analysis aimed to evaluate the prognostic accuracies of the aortic isthmus Doppler to predict adverse perinatal outcomes in singleton pregnancies with FGR.

METHODS

PubMed, EMBASE, the Cochrane Library, ClinicalTrials.gov and Google scholar were searched from inception to May 2021, for studies on the prognostic accuracy of anterograde aortic isthmus flow compared with retrograde aortic isthmus flow in singleton pregnancy with FGR. The meta-analysis was registered on PROSPERO and was assessed according to PRISMA and Newcastle-Ottawa Scale. DerSimonian and Laird's random-effect model was used for relative risks, Freeman-Tukey Double Arcsine for pooled estimates and exact method to stabilize variances and CIs. Heterogeneity was quantified using I2 statistics.

RESULTS

A total of 2933 articles were identified through the electronic search, of which 6 studies (involving 240 women) were included. The quality evaluation of studies revealed an overall acceptable score for study group selection and comparability and substantial heterogeneity. The risk of perinatal death was significantly greater in fetuses with retrograde Aortic Isthmus blood flow, with a RR of 5.17 (p value 0.00001). Similarly, the stillbirth rate was found to have a RR of 5.39 (p value 0.00001). Respiratory distress syndrome had a RR of 2.64 (p value = 0.03) in the group of fetuses with retrograde Aortic Isthmus blood flow.

CONCLUSION

Aortic Isthmus Doppler study may add information for FGR management. However, additional clinical trial are required to assess its applicability in clinical practice.

Retrograde flow in aortic isthmus in normal and fetal heart disease by principal component analysis and computational fluid dynamics

OBJECTIVES

Reverse flow Retrograde flow (RF) of blood in the aortic isthmus can be observed in different types of fetal heart disease (FHD), including abnormalities in heart structure and function. This study sought to investigate the relationship between RF and blood flow parameters, and develop a computational fluid dynamics (CFD) model to understand the mechanisms underlying this observation.

MATERIAL AND METHODS

A total of 281 fetuses (gestational age [GA] 26.6±.3 weeks) with FHD and 2803 normal fetuses (GA: 26.1±.1 weeks) by fetal echocardiography collected from May 2016 to December 2018. Principal component analysis (PCA) was performed to find the relationship and the CFD model reconstructed from 3D/4D spatio-temporal image correlation (STIC) images to simulate hemodynamics.

RESULTS

There was a significant difference in the percentages of RF between the study (80/201 (39%)) and control (29/2803 (1%)) groups (p < 0.05). The RF occur when the aorta flow rate (left heart) is reduced to 60% by CFD stimulation. Pearson correlation analysis showed significant correlations between flow rate and wall shear stress(WSS) (r = .883, p = 0.047) variables at the AI.

CONCLUSION

Volumetric flow rate of AO or left heart was the main component of the cause of RF. The hemodynamics of the cardiovascular system have highly complex behavior hinge on the turbulent nature of circulating blood flow.

Cerebroplacental ratio and aortic isthmus Doppler in early fetal growth restriction

PURPOSE

To assess the utility of cerebroplacental ratio (CPR) and fetal aortic isthmus (AoI) Doppler in the prediction of perinatal outcome in early fetal growth restriction (FGR).

METHODS

A prospective observational cohort study of 70 early FGR cases was conducted through serial Doppler examinations and findings of the last examination were correlated with perinatal outcome. Doppler blood flow measurements of AoI included end diastolic velocity (EDV), peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI), and isthmic flow index (IFI).

RESULTS

Significant association of CPR and all Doppler indices of AoI with the overall adverse perinatal outcome was seen. The sensitivity of CPR was moderate (63.64%) but higher than most AoI indices. Most AoI Doppler indices (PI, RI, IFI) had higher specificities (100%). AoI PSV and EDV had higher sensitivities than CPR for the prediction of overall adverse perinatal outcome, with AoI PSV having the highest sensitivity (100%).

CONCLUSION

CPR shows significant association and moderate sensitivity for prediction of overall adverse perinatal outcome in early FGR; hence recommended in all cases of early FGR. AoI Doppler also appears to have a role in assessment and decision making in FGR in view of high sensitivity and high specificity of AoI indices in the prediction of perinatal outcome. However, larger studies are required to confirm its utility in the management of early FGR.

Cardiac function in fetal growth restriction

Fetal growth restriction (FGR) is defined as the inability of the fetus to reach its growth potential. According to the onset of the disease is defined early (<32 weeks) or late (≥32 weeks). FGR is associated with an increased risk of adverse short- and long-term outcomes, including hypoxemic events and neurodevelopmental delay compared to normally grown fetuses and increased risk of complications in the infanthood and adulthood. The underlying cause of FGR is placental insufficiency leading to chronic fetal hypoxia that affects cardiac hemodynamic with different mechanism in early and late onset growth restriction. In early onset FGR adaptive mechanisms involve the diversion of the cardiac output preferentially in favor of the brain and the heart, while abnormal arterial and venous flow manifest in the case of further worsening of fetal hypoxia. In late FGR the fetal heart shows a remodeling of its shape and function mainly related to a reduction of umbilical vein flow. In this review we discuss the modifications occurring at the level of the fetal cardiac hemodynamic in fetuses with early and late FGR.

Doppler studies of placental function

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Doppler evaluation has been incorporated as a predictive parameter at early pregnancy for high-risk placental disease, in the diagnosis and management of those fetuses with impaired intrauterine growth and for the evaluation of fetal wellbeing in those high-risk pregnancies. Uterine Doppler at second trimester predicts most instances of early-onset preeclampsia and intrauterine growth restriction. However, the growing evidence of an effective early propylactic strategy, has turned Uterine Doppler an essential parameter to be included in first trimester predictive algorithms. Umbilical artery Doppler helps in the identification of small-for-gestational-age fetuses at higher risk, and is one of the essential vessels in the assessment of fetal hypoxia impairment, especially in the early cases. It helps in the decision timing for ending the pregnancy improving thus perinatal outcomes. Moreover, in high-risk pregnancies, umbilical artery Doppler has demonstrated to reduce the risk of perinatal deaths and the risk of obstetric interventions. On the other hand, middle cerebral artery Doppler reflects fetal adaptation to hypoxia, and with the cerebroplacental ratio, they improve the detection of fetuses a high risk of adverse perinatal outcome, mostly of those late small fetuses, where most instances of adverse outcome occur in fetuses with normal umbilical artery. Ductus venosous Doppler waveform is a surrogate parameter of the fetal base-acid status. Its use has demonstrated to improve perinatal outcomes, mainly reducing the risk of fetal intrauterine death. Alone or in combination with computerized CTG, it helps tailoring the best moment to end the pregnancy among early cases.

Aortic isthmus Doppler in normal and small-for-gestational-age fetuses and its association with prediction of adverse perinatal outcome

OBJECTIVE

To establish reference ranges for aortic isthmus Doppler indices in appropriate-for-gestational-age (AGA) fetusesand to evaluate its association with perinatal outcome in small-for-gestational-age (SGA) fetuses.

METHODS

Prospective cohort observational study in which 30 pregnant women with SGA fetuses and 60 women with AGA fetuses were recruited from the prenatal clinic of the hospital. The AGA group was eventually followed from 24 weeks by 4-weekly Doppler assessment, and the SGA group was examined as per institutional protocol. We analyzed the data using STATA version 14.0 statistical software. Continuous variables were examined for normality assumption using the Kolmogorov-Smirnov test. To develop a nomogram for appropriate gestational age, we adopted a mixed linear model analysis. For each of the variables Ao pulsatility index (PI), Ao peak systolic velocity (PSV), Ao systolic nadir (Ns), and Ao isthmic systolic index (ISI) mean predicted values, 3rd centile and 97th centile were calculated based on the parameter estimation of mixed model. Observed data for each of the variables in the SGA group were plotted in the nomogram developed for the AGA group to show the trend of SGA data in comparison to AGA data.

RESULTS

The total number of observations made on 60 AGA and 30 SGA fetuses were 240 and 67, respectively. Nomograms for the 3rd and 97th centiles were derived for Ao PI, Ao PSV, Ao Ns, and Ao ISI. Mean Ao PI values were significantly higher in SGA group (2.37 vs 2.22; P < .05); mean Ao PSV was significantly lower in the SGA group (67.1 vs 76.3; P < .05), but mean Ao Ns and mean Ao ISI values were significantly higher in the SGA group (-5.24 vs 2.0 and -0.04 vs -0.01; P < .05).

CONCLUSIONS

Aortic Doppler assessment seems to provide beneficial information for monitoring small fetuses. Ao PI and Ao ISI, which were raised in fetuses with SGA, can be used in prognosis.

Aortic Isthmus Doppler Velocimetry in Fetuses with Intrauterine Growth Restriction: A Literature Review

Intrauterine growth restriction (IUGR) is associated with poor perinatal prognosis and a higher risk of stillbirth, neonatal death, and cerebral palsy. Its detection and the evaluation of its severity by new Doppler velocimetric parameters, such as aortic isthmus (AoI), are of great relevance for obstetrical practice. The AoI is a vascular segment that represents a point of communication between the right and left fetal circulations. It is considered to be a functional arterial shunt that reflects the relationship between the systemic and cerebral impedances, and has recently been proposed as a tool to detect the status of hemodynamic balance and prognosis of IUGR in fetuses. In the present review, we noticed that in healthy fetuses, the AoI net flow is always antegrade, but in fetuses with IUGR the deterioration of placental function leads to progressive reduction in its flow until it becomes mostly retrograde; this point is associated with a drastic reduction in oxygen delivery to the brain. The more impaired the AoI flow is, the greater is the risk of impairment in the Doppler velocimetry of other vessels; and the alterations of the AoI Doppler seem to precede other indicators of severe hypoxemia. Although there seems to be an association between the presence of retrograde flow in the AoI and the risk of long-term neurologic disability, its role in the prediction of perinatal morbi-mortality remains unclear. The AoI Doppler seems to be a promising tool in the management of fetuses with IUGR, but more studies are needed to investigate its employment in clinical practice.

Prenatal Identification of Restrictive and Non-restrictive Ventricular Septal Defects Based on End-Systolic Flow Patterns in the Fetal Aortic Isthmus

Fetuses with large ventricular septal defects (VSDs) must be closely monitored during the perinatal period. Intrauterine assessment of size of septal defects with bidimensional echocardiography are unreliable. The objective of the present study is to document the contribution of flow pattern analysis in the fetal aortic isthmus for prenatal identification of large non-restrictive VSDs requiring immediate postnatal attention. We conducted a cross-sectional retrospective study of Doppler recordings from patients referred to our Fetal Cardiology Unit and diagnosed with one or multiple VSDs from January 2006 to November 2015. Three groups were defined: (1) large non-restrictive VSDs (n = 11) with postnatal cardiac failure (2) small restrictive VSDs (n = 28) asymptomatic, and (3) absence of cardiac abnormality (n = 66). The Isthmic end-Systolic Index (ISI) was computed to quantify aortic isthmus flow and compared between the three groups. Fetuses with restrictive VSD and control group showed similar ISI: stable at 0.20 ± 0.01 up to 27 weeks of gestation and dropping later due to the fall of end-systolic velocities in the aortic isthmus. By 35 weeks, a brief end-systolic retrograde flow was present, associated with a further fall of ISI down to -0.26 ± 0.05. In contrast, ISI of fetuses with large non-restrictive VSDs were unchanged throughout gestation (0.18 ± 0.06), becoming significantly higher during the last weeks of gestation compared to the two other groups (p < 0.001). In fetuses with VSDs, the ISI measurement from the aortic isthmus Doppler flow during the second half of gestation is a reliable predictor of a large non-restrictive defect with risk of major postnatal clinical impact.

Color Doppler sonography of the aortic isthmus in intrauterine growth-restricted fetuses and normal fetuses

Intrauterine growth restriction is associated with a significant increase in morbidity and perinatal mortality, and increases the likelihood of fetal death, asphyxia, meconium aspiration, hypoglycemia, and neonatal hypothermia. The aim of this study was to determine aortic isthmus flow difference by using color doppler sonography in Intrauterine growth restriction and normal fetuses. The data presented were obtained from 30 mothers, who referred to the radiology department of Akbarabadi Hospital of Tehran with a diagnosis of intrauterine growth restriction. An ultrasound was performed to determine the status of placenta, fetus, and amniotic fluid. The umbilical arterial doppler assessment was used to confirm diagnosis of intrauterine growth restriction. Thirteen (43.3%) were nulliparous mothers and 17 (56.7%) were multiparous mothers. 30 pregnant women with healthy fetuses were enrolled as control group. According to the ultrasound findings, Dactus Venus wave type was recorded in intrauterine growth restriction fetuses, which was reported as normal (26 subjects; 86.7%) and abnormal (4 subjects; 13.3%). All together, this study provides appropriate guidance to use doppler for delivery timing and to control risk factors.

Behaviour of the Foramen Ovale Flow in Fetuses with Intrauterine Growth Restriction

Background

Foramen ovale (FO) flow may be altered in IUGR. This study was designed to test this hypothesis.

Methods

Forty pregnant women (24–38 weeks) were divided into 3 groups: group I (IUGR), group II (adequate growth and maternal hypertension), and group III (normal controls). Impedance across the FO was assessed by the FO pulsatility index (FOPI): (systolic velocity − presystolic velocity)/mean velocity. Statistical analysis utilized ANOVA, Tukey test, and ROC curves.

Results

Mean FOPI in IUGR fetuses (n = 15) was 3.70 ± 0.99 (3.15–4.26); in the group II (n = 12), it was 2.84 ± 0.69 (2.40–3.28), and in the group III (n = 13), it was 2.77 ± 0.44 (2.50–3.04) (p=0.004). FOPI and UtA RI were correlated (r = 0.375, p=0.017), as well as FOPI and UA RI (r = 0.356, p=0.024) and, inversely, FOPI and MCA RI (r = −0.359, p=0.023).

Conclusions

The FO flow pulsatility index is increased in fetuses with IUGR, probably as a result of impaired left ventricular diastolic function.

Aortic isthmus shunt dynamics in normal and complicated monochorionic pregnancies

OBJECTIVE

To study fetal aortic isthmus (AoI) shunt dynamics in monochorionic (MC) twins.

METHODS

Normal and complicated MC pregnancies were prospectively enrolled. The relationship of isthmus flow index (IFI) with Doppler parameters of umbilical artery (UA), descending aorta, middle cerebral artery, and ductus venosus and with left and right ventricular cardiac output and stroke volume was studied.

RESULTS

The IFI was obtained in 180 examinations from 48 pregnancies (24 twin-twin transfusion syndrome, TTTS; 4 selective intrauterine growth restriction, sIUGR; 12 TTTS + sIUGR; and 8 uncomplicated). Median gestational age was 20.9 weeks. AoI diastolic flow was reversed in three cases. UA pulsatility index (PI) and ductus venosus-PI z-scores were negatively correlated with the IFI (r_s -0.40 and -0.26, respectively, p < 0.001). Regression analysis identified only UA-PI as a determinant of the IFI (p < 0.001). The IFI was significantly correlated with left ventricular cardiac output and stroke volume. It did not differ between TTTS donors and recipients. sIUGR fetuses had significantly lower IFI compared with normal-grown counterparts (p < 0.001).

CONCLUSION

In MC gestations, AoI shunting is predominantly determined by placental flow resistance, while cerebral impedance and volume status have no impact. In MC twins, the relationship between AoI flow and outcome deserves further study in the setting of sIUGR. © 2017 John Wiley & Sons, Ltd.

Early onset fetal growth restriction

Fetal growth restriction (FGR) diagnosed before 32 weeks is identified by fetal smallness associated with Doppler abnormalities and is associated with significant perinatal morbidity and mortality and maternal complications. Recent studies have provided new insights into pathophysiology, management options and postnatal outcomes of FGR. In this paper we review the available evidence regarding diagnosis, management and prognosis of fetuses diagnosed with FGR before 32 weeks of gestation.

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.

The Aortic Isthmus: A Significant yet Underexplored Watershed of the Fetal Circulation

The aortic isthmus (AoI) is a unique fetal watershed with a waveform reflecting its complex haemodynamic physiology. The systolic component represents left and right ventricular systolic ejection, and the diastolic component represents comparative downstream vascular impedance between the brachiocephalic and subdiaphragmatic fetal circulations. Several indices have been devised to quantify different components of the waveform, including the pulsatility index, resistance index, isthmic flow index, and recently the isthmic systolic index. There have been promising preliminary studies applying these indices to both cardiac (congenital) and extracardiac pathologies, including intrauterine growth restriction and twin-twin transfusion syndrome. However, the waveform's multifactorial origin has proven to be challenging, and the difficulty in separating various components of the waveform could explain that AoI evaluation does not have a clear clinical utility. Further research is underway to realise the full potential of this vessel in fetal cardiac and haemodynamically compromised pathological conditions. In this review article we outline the physiological origin of this Doppler waveform, describe in detail the various published indices, summarise the published literature to date, and finally outline potential future research and hopefully clinical applications.

Risk of ultrasound-detected neonatal brain abnormalities in intrauterine growth-restricted fetuses born between 28 and 34 weeks' gestation: relationship with gestational age at birth and fetal Doppler parameters

OBJECTIVE

To estimate the value of gestational age at birth and fetal Doppler parameters in predicting the risk of neonatal cranial abnormalities in intrauterine growth-restricted (IUGR) fetuses born between 28 and 34 weeks' gestation.

METHODS

Fetal Doppler parameters including umbilical artery (UA), middle cerebral artery (MCA), aortic isthmus, ductus venosus and myocardial performance index were evaluated in a cohort of 90 IUGR fetuses with abnormal UA Doppler delivered between 28 and 34 weeks' gestation and in 90 control fetuses matched for gestational age. The value of gestational age at birth and fetal Doppler parameters in predicting the risk of ultrasound-detected cranial abnormalities (CUA), including intraventricular hemorrhage, periventricular leukomalacia and basal ganglia lesions, was analyzed.

RESULTS

Overall, IUGR fetuses showed a significantly higher incidence of CUA than did control fetuses (40.0% vs 12.2%, respectively; P < 0.001). Within the IUGR group, all predictive variables were associated individually with the risk of CUA, but fetal Doppler parameters rather than gestational age at birth were identified as the best predictor. MCA Doppler distinguished two groups with different degrees of risk of CUA (48.5% vs 13.6%, respectively; P < 0.01). In the subgroup with MCA vasodilation, presence of aortic isthmus retrograde net blood flow, compared to antegrade flow, allowed identification of a subgroup of cases with the highest risk of CUA (66.7% vs 38.6%, respectively; P < 0.05).

CONCLUSION

Evaluation of fetal Doppler parameters, rather than gestational age at birth, allows identification of IUGR preterm fetuses at risk of neonatal brain abnormalities.

Fetal-maternal interface impedance parallels local NADPH oxidase related superoxide production

Blood flow assessment employing Doppler techniques is a useful procedure in pregnancy evaluation, as it may predict pregnancy disorders coursing with increased uterine vascular impedance, as pre-eclampsia. While the local causes are unknown, emphasis has been put on reactive oxygen species (ROS) excessive production. As NADPH oxidase (NOX) is a ROS generator, it is hypothesized that combining Doppler assessment with NOX activity might provide useful knowledge on placental bed disorders underlying mechanisms. A prospective longitudinal study was performed in 19 normal course, singleton pregnancies. Fetal aortic isthmus (AoI) and maternal uterine arteries (UtA) pulsatility index (PI) were recorded at two time points: 20-22 and 40-41 weeks, just before elective Cesarean section. In addition, placenta and placental bed biopsies were performed immediately after fetal extraction. NOX activity was evaluated using a dihydroethidium-based fluorescence method and associations to PI values were studied with Spearman correlations. A clustering of pregnancies coursing with higher and lower PI values was shown, which correlated strongly with placental bed NOX activity, but less consistently with placental tissue. The study provides evidence favoring that placental bed NOX activity parallels UtA PI enhancement and suggests that an excess in oxidation underlies the development of pregnancy disorders coursing with enhanced UtA impedance.

Reference ranges for the pulsatility index of the fetal aortic isthmus in singleton and twin pregnancies

OBJECTIVES

The purpose of this study was to estimate reference ranges for the pulsatility index (PI) of the fetal aortic isthmus in uncomplicated singleton and twin pregnancies during the second half of pregnancy.

METHODS

We conducted a cross-sectional observational study involving 543 healthy fetuses: 361 singleton pregnancies and 182 twin pregnancies between 19 and 36 weeks' gestation. The aortic isthmus PI was measured in 2 sonographic planes: the longitudinal aortic arch view and the 3-vessel and trachea view. We evaluated the reproducibility of aortic isthmus PI measurements between these planes by calculating intraclass correlation coefficients and limits of agreement. Scans were performed by 2 physicians, and intraobserver agreement was also measured. Regression analysis was used to estimate gestational age reference values for the aortic isthmus PI.

RESULTS

The aortic isthmus PI was significantly correlated with gestational age in singletons and twins during the second half of pregnancy (P < .01). We did not find significant differences between reference ranges in singletons and twins or between the sonographic views.

CONCLUSIONS

This study offers reference ranges for the aortic isthmus PI during the second half of gestation in singleton and twin pregnancies. Mean aortic isthmus PI values were similar in both types of gestations as well as both sonographic views. The aortic isthmus PI may be reliably obtained from either sonographic view.

Doppler assessment of fetal aortic isthmus flow in twin

Objective

The purpose of this study was to investigate the aortic isthmus (AoI) flow difference between larger fetus and smaller fetus of twin; and to evaluate the predictive value of early diagnosis of hemodynamic change in twin growth.

Methods

This prospective study on 49 pairs of twin fetuses was performed to obtain AoI blood flow data. Cases with structural or chromosomal abnormalities and co-twin death were excluded. The interval from examination to delivery was within 4 weeks and 3 cases over 4 weeks interval were re-examined. Assessment of fetal AoI Doppler parameters were peak systolic velocity (PSV), end-diastolic velocity, times-averaged maximum velocities, pulsatility index (PI), and resistance index (RI). According to the direction of the diastolic flow in the AoI, antegrade and retrograde flow were made and was used to analyze the perinatal outcomes of each fetus. The predictive value of AoI Doppler parameters in predicting fetal growth was obtained by using ANOVA and logistic regression analysis of quantitative variables in each fetus of twins.

Results

There were significant differences in the gestational weeks at delivery, birth weight and the incidence of growth discordance over 20% or more between monochorionic twin and dichorionic twin. The AoI PI and RI were significantly higher in smaller fetus than in larger regardless of chorionicity. Retrograde flow was noted in 8 of 98 cases (8.2%) and the only one case was of the larger fetus and the others were smaller fetuses of twin. Significant correlations were found between the AoI PI and birthweight (P=0.018) and between the PSV and growth discordance (P=0.032). In monochorionic twin, linear correlation was shown between the AoI PI and birthweight (P=0.004) and between AoI PI and growth discordance (P=0.031). Also, the meaningful correlation between the PSV and birthweight (P=0.036) was found by using logistic regression analyses.

Conclusion

On the basis of our observation, AoI PI has revealed their hemodynamic status and this result may improve the understanding of growth patterns in twins.

Profiling left and right ventricular proportional output during fetal life with a novel systolic index in the aortic isthmus

OBJECTIVE

Left ventricular ejection causes forward flow in the fetal aortic isthmus while the right ventricle has a retrograde influence. The aim of this study was to create reference values for an isthmic systolic index (ISI) reflecting the changing influence of right and left ventricular performance on Doppler flow velocity waveforms of the aortic isthmus throughout normal pregnancy.

METHODS

Doppler recordings of 260 normal fetuses with a gestational age of 18-37 weeks were reviewed. Peak systolic velocity (PSV) and end-systolic velocity (or systolic nadir; Ns) were measured on all aortic isthmus waveforms. An ISI was derived from the ratio Ns/PSV. Left and right ventricular outputs were also calculated.

RESULTS

Up to 22-23 weeks' gestation, the mean ISI is stable at around 0.2. At about 28 weeks, a brief end-systolic deceleration wave is observed on the aortic isthmus waveforms, progressing steadily with gestation and causing a fall of ISI towards a mean value of zero between 30 and 31 weeks. This trend continues thereafter and a mean value of -0.4 was observed at the end of pregnancy. An inverse correlation was found between right ventricular output and Ns (r = -0.334, P = 0.001). Simultaneous recordings of the isthmus and the ductus arteriosus Doppler waveforms demonstrated that the primary cause of the end-systolic deceleration and ultimate reversal of flow at the isthmus is the increasingly dominant flow from the right ventricle.

CONCLUSION

The transitional changes of the respective right and left ventricular outputs throughout pregnancy are well profiled by the ISI. This index highlights the physiological increase in fetal right ventricle flow preponderance as pregnancy progresses. Alteration of the ISI profile could be expected in clinical conditions associated with unbalanced alteration of the fetal ventricular outputs.

Reference values for fetal aortic isthmus blood flow parameters at 24 to 38 weeks' gestation

OBJECTIVE

The goal of this study is to establish population-specific nomograms of fetal aortic isthmus (AoI) Doppler indices in the period of 24-38 weeks' gestation.

METHODS

This was a cross-sectional study of 240 Asian singleton pregnant women at 24-38 completed weeks' gestation. Fetal AoI blood flow was evaluated by Doppler study with automatic calculation of pulsatility index, resistance index, peak systolic velocity, end-diastolic velocity, and time-averaged maximum velocity. The relationship of these indices and gestational age was estimated by using regression analysis, and the best predictive models were determined to define mean, 5th, and 95th centile of each gestational age. The reproducibility was expressed by intraclass correlation coefficients and limits of agreement.

RESULTS

The mean maternal age was 28 ± 5.7 years. A total of 97% of all attempts to obtain AoI Doppler waveforms were successful with high interobserver and intraobserver reproducibility. Pulsatility index and peak systolic velocity significantly correlated with gestational age (P = 0.03 and 0.001, respectively), whereas no significant change of resistance index, end-diastolic velocity, and time-averaged maximum velocity with advancing gestation was observed.

CONCLUSION

This study offers normative values of fetal AoI Doppler indices, which may be useful in the difficult task of fetal surveillance in growth-restricted fetuses among our population.

Longitudinal study of aortic isthmus Doppler in appropriately grown and small-for-gestational-age fetuses with normal and abnormal umbilical artery Doppler

OBJECTIVE

To establish reference ranges using longitudinal data for aortic isthmus (AoI) Doppler indices in appropriate-for-gestational-age (AGA) fetuses and to document the longitudinal trends in a cohort of small-for-gestational-age (SGA) fetuses with normal umbilical artery Doppler and in fetuses with intrauterine growth restriction (IUGR) and abnormal umbilical artery Doppler.

METHODS

AoI Doppler reference ranges were established from longitudinal data on 72 AGA singleton fetuses. Reliability of AoI Doppler flow measurements at two different sites and reproducibility between two operators was reviewed. A prospective longitudinal study of AoI Doppler indices in 48 SGA fetuses with normal umbilical artery Doppler and 10 IUGR fetuses was performed.

RESULTS

The AoI pulsatility index (PI) and peak systolic velocity (PSV) in AGA fetuses showed a significant increase with gestational age. Analysis of intra- and interoperator variability revealed no significant mean difference in measurements of AoI-PI or AoI-PSV. Observations of AoI-PI and AoI-PSV from SGA fetuses did not differ significantly from those of AGA or IUGR fetuses. Retrograde flow in the AoI did not predate changes in the ductus venosus in IUGR fetuses.

CONCLUSIONS

Reference ranges for fetal AoI Doppler parameters in AGA fetuses constructed using longitudinal data are consistent with those obtained from cross-sectional data. The AoI Doppler parameters in SGA fetuses did not differ from those in AGA fetuses. Preterm IUGR fetuses did not manifest alterations in AoI-PI or AoI-PSV prior to changes in biophysical profile or ductus venosus Doppler. Further large-scale prospective studies are needed to determine whether AoI Doppler parameters are of any value in timing delivery or reducing adverse neurodevelopmental outcome.

Assessment of uterine artery and aortic isthmus Doppler recordings as predictors of necrotizing enterocolitis

OBJECTIVE

The purpose of this study was to evaluate whether changes of uterine arteries and aortic isthmus Doppler blood flow recordings could enhance the prediction of necrotizing enterocolitis.

STUDY DESIGN

Doppler characteristics of the uterine artery, umbilical and middle cerebral arteries, ductus venosus, and aortic isthmus were reviewed in 123 growth-restricted fetuses who were then divided into 2 groups: with and without necrotizing enterocolitis.

RESULTS

Twelve of 123 newborn infants (9%) expressed necrotizing enterocolitis. This group showed significant association between necrotizing enterocolitis and bilateral notching on the uterine artery (83.3% vs 29.7%; P < .001), uterine artery mean resistance index (83.3% vs 36.9%; P < .002), aortic isthmus diastolic blood flow velocity integrals (Z score: -7.32 vs -3.99; P = .028), and absent or negative "a" wave on the ductus venosus (17% vs 1.8%; P = .021). With the use of logistic regression, uterine bilateral notching could predict necrotizing enterocolitis with a sensitivity of 83.3% and a specificity of 70.3%.

CONCLUSION

More than any other variable, uterine bilateral notching should be recognized as a strong risk factor for necrotizing enterocolitis.

Aortic isthmus blood flow in fetuses of diabetic mothers

OBJECTIVE

To test the hypothesis that the aortic isthmus flow index (IFI) is lower in fetuses of diabetic mothers than in fetuses of nondiabetic mothers.

STUDY DESIGN

We performed a cross-sectional observational study to assess the IFI in fetuses, with (n = 13) and without (n = 37) myocardial hypertrophy, of mothers with diabetes mellitus and in fetuses of nondiabetic mothers (n = 23). Analysis of variance and Tukey test were used to assess differences among the groups.

RESULTS

There were no differences in maternal or gestational age among the groups. In fetuses of diabetic mothers, the mean IFI in fetuses with myocardial hypertrophy was 1.19 ± 0.06, and in fetuses without it was 1.18 ± 0.09. The mean IFI in fetuses of nondiabetic mothers was 1.32 ± 0.07 (P < 0.001).

CONCLUSIONS

The IFI in fetuses of diabetic mothers is lower than in fetuses of nondiabetic mothers, possibly as a result of a decreased left ventricular compliance.

Changes in myocardial performance index and aortic isthmus and ductus venosus Doppler in term, small-for-gestational age fetuses with normal umbilical artery pulsatility index

OBJECTIVE

To evaluate the changes in myocardial performance index (MPI) and aortic isthmus (AoI) and ductus venosus (DV) Doppler in term, small-for-gestational age (SGA) fetuses with normal umbilical artery (UA) Doppler.

METHODS

MPI, AoI and DV pulsatility indices (PI) were measured within 1 week prior to delivery in a cohort of 178 term singleton consecutive SGA fetuses with normal UA-PI (< 95(th) percentile) and 178 controls matched by gestational age. Cardiovascular parameters were converted into Z-scores and values above the 95(th) centile defined as abnormal.

RESULTS

Median gestational age at inclusion and at delivery was 35.7 and 38.6 weeks, respectively. Compared to controls, SGA fetuses showed significantly higher values in MPI and AoI-PI and similar values in DV-PI. SGA fetuses showed a significantly higher proportion of increased MPI (28.1 vs. 6.7%; P < 0.01) and abnormal AoI-PI (14.6 vs. 5.1%; P < 0.01) than controls. The proportion of cases with abnormal DV-PI was similar between SGA cases and controls. Retrograde net blood flow in the AoI was observed in 7.3% of the SGA cases and in none of the controls.

CONCLUSION

A proportion of SGA fetuses show cardiovascular Doppler abnormalities. This information might be of clinical relevance in improving the detection and management of late-onset intrauterine growth restriction.

Sequence of changes in myocardial performance index in relation to aortic isthmus and ductus venosus Doppler in fetuses with early-onset intrauterine growth restriction

OBJECTIVE

To explore the sequence of changes in myocardial performance index (MPI) and aortic isthmus (AoI) and ductus venosus (DV) flow in fetuses with early-onset intrauterine growth restriction (IUGR).

METHODS

MPI and AoI and DV pulsatility indices (PI) were evaluated every 1-7 days in a cohort of IUGR fetuses with abnormal umbilical artery Doppler PI (> 95(th) percentile) delivered before 34 weeks' gestation. The longitudinal changes were analyzed in the last 30 days before delivery by multilevel and survival analysis.

RESULTS

A total of 430 scans were performed on 115 IUGR fetuses. MPI, AoI-PI and DV-PI showed increases with the progression of fetal deterioration throughout the follow-up study period, but the rates of progression were different. On average, MPI, AoI-PI and DV-PI crossed the 95(th) percentile at 26 days, 12 days and 5 days before delivery, respectively. At the last examination before delivery, the proportion of increased MPI (70.4%) was significantly higher than that of abnormal AoI-PI (55.7%; P < 0.01) and DV-PI (47.8%; P < 0.01).

CONCLUSION

In early-onset IUGR, MPI and AoI and DV Doppler indices all increase but at different rates, which could provide the basis for further research on their use for improving in-utero monitoring and prediction of long-term outcome.

The importance of venous Doppler velocimetry for evaluation of intrauterine growth restriction

The management of growth-restricted fetuses requires accurate diagnosis to optimize the timing of delivery. Doppler velocimetry is the only noninvasive method for assessing the fetoplacental hemodynamic status. This review will give a critical overview of the current knowledge on fetal venous blood flow in pregnancies complicated by in-trauterine growth-restricted fetuses. Adaptation of the circulation in intrauterine growth-restricted fetuses is described. Normal and abnormal venous Doppler waveforms are presented. Correlations of abnormal waveforms with the presence of acidemia and perinatal outcomes are emphasized. Limitations of venous Doppler velocimetry for optimizing the time for delivery and the perinatal outcome are also presented.

Aortic isthmus and cardiac monitoring of the growth-restricted fetus

Aortic isthmus acts as an arterial watershed between the cerebral and placental circulations, connecting 2 parallel fetal ventricular pumps. It plays a crucial role in the fetal circulatory dynamics. Information about aortic isthmus blood flow may improve the management of sick fetuses. However, perceived technical difficulties limit the clinical use of aortic isthmus Doppler for fetal hemodynamic monitoring. Changes in aortic isthmus blood flow pattern seem to reflect fetal cardiovascular status accurately and predict perinatal and long-term neurodevelopmental outcome in intrauterine growth restriction. This review evaluates the available scientific information and discusses the role of aortic isthmus in fetal circulation.

Systematic review and meta-analysis of the test accuracy of ductus venosus Doppler to predict compromise of fetal/neonatal wellbeing in high risk pregnancies with placental insufficiency

OBJECTIVE

To evaluate the test accuracy of ductus venosus Doppler for prediction of compromise of fetal/neonatal wellbeing.

STUDY DESIGN

The search strategy employed searching of electronic databases (Medline, Embase, Cochrane library, Medion) from inception to May 2009, hand searching of journal and reference lists, contact with experts. Two reviewers independently selected articles in which the results of ductus venosus Doppler were associated with the occurrence of compromise of fetal/neonatal wellbeing. There were no language restrictions applied. Data were extracted on study characteristics, quality and results to construct 2 x 2 tables. Likelihood ratios for positive and negative test results, sensitivity, specificity and their 95% confidence intervals were generated for the different indices and thresholds.

RESULTS

Eighteen studies, testing 2267 fetuses met the selection criteria, all performed in a high risk population with placental insufficiency in second/third trimester. Meta-analysis showed moderate predictive accuracy. The best result was for the prediction of perinatal mortality, positive likelihood ratio 4.21 (95% CI 1.98-8.96) and negative likelihood ratio 0.43 (95% CI 0.30-0.61). For prediction of adverse perinatal outcome the results were positive likelihood ratio 3.15 (95% CI 2.19-4.54) and negative likelihood ratio 0.49 (95% CI 0.40-0.59).

CONCLUSION

Abnormal ductus venosus Doppler showed moderate predictive accuracy for compromise of fetal/neonatal wellbeing overall and perinatal mortality in high risk pregnancies with placental insufficiency.

Does pre-eclampsia influence fetal cardiovascular function in early-onset intrauterine growth restriction?

OBJECTIVES

Increasing evidence shows that intrauterine growth restriction (IUGR) is associated with fetal cardiac dysfunction. Most studies group IUGR with and without pre-eclampsia (PE) altogether. Our objective was to evaluate whether the association with PE has any impact on cardiac function in IUGR fetuses

METHODS

Thirty-one normotensive IUGR cases and 31 IUGR cases with pre-eclampsia (PE + IUGR) below 34 weeks of gestation were included. IUGR was defined as a birth weight below the 10(th) centile together with an umbilical artery pulsatility index above 2 SD. Fetal cardiac function was assessed by measuring ductus venosus pulsatility index, modified myocardial performance index, aortic isthmus blood flow, E/A ratios and cardiac output. The presence of fetal cardiac dysfunction was also assessed by measuring cord blood B-type natriuretic peptide (BNP) levels collected at birth. Echocardiographic data were compared with those in 80 term appropriate-for-gestational age (AGA) fetuses from normotensive mothers. Cord blood BNP levels were compared with those in 40 AGA cases that delivered preterm.

RESULTS

All IUGR cases (with or without PE) showed echocardiographic and biochemical signs of cardiac dysfunction compared with AGA cases. However, no differences were observed between IUGR and PE + IUGR cases either in echocardiographic or in biochemical parameters. IUGR cases with or without PE had similar perinatal results.

CONCLUSIONS

IUGR fetuses showed echocardiographic and biochemical signs of cardiac dysfunction. Pre-eclampsia per se does not influence cardiac function in IUGR fetuses.

Contribution of the myocardial performance index and aortic isthmus blood flow index to predicting mortality in preterm growth-restricted fetuses

OBJECTIVES

To evaluate the predictive value for perinatal death of the myocardial performance index (MPI) and aortic isthmus flow index (IFI), as isolated parameters and in a combined model including currently used Doppler indices, in preterm growth restricted (IUGR) fetuses.

METHODS

Umbilical artery, fetal middle cerebral artery (MCA) and ductus venosus (DV) pulsatility indices (PIs) were recorded, along with IFI and MPI, in a cohort of 97 preterm (delivered at between 24 and 34 weeks) IUGR fetuses. Logistic regression analysis was performed to identify those variables that were independently associated with perinatal mortality, and an algorithm to estimate probability of death was constructed including the best combination of parameters.

RESULTS

With the exception of MCA, all Doppler indices were significantly associated with perinatal death as isolated parameters, but only DV-PI and MPI were found to be independent predictors on multivariate analysis. An algorithm combining DV atrial flow (positive or absent/reversed) and MPI (normal or above 95(th) percentile) had a better predictive accuracy than did any single parameter. The risk for death in IUGR fetuses below 28 weeks' gestation with present atrial flow in the DV and normal MPI was 18%, with either characteristic abnormal it was 70-73%, and with both abnormal it was 97%. The risk for death in IUGR fetuses above 28 weeks with present atrial flow in the DV and normal MPI was 0.1%, with either abnormal it was 6-7%, and with both abnormal it was 45%.

CONCLUSIONS

MPI is an independent predictor of perinatal death in preterm IUGR fetuses with accuracy similar to that of DV flow. A combination of DV flow with MPI may better stratify the estimated probability of death. IFI does not add to the prediction of perinatal death when used in combination with DV flow.

The role of Doppler and placental screening

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Uterine Doppler evaluation predicts most instances of early-onset preeclampsia and intrauterine growth restriction, but there is no evidence in favour of any prophylactic strategy in cases of an abnormal screening result. Umbilical artery Doppler investigation allows identifying those small-for-gestational-age foetuses at higher risk, and its use in these pregnancies improves a number of perinatal outcomes. Middle cerebral artery Doppler investigation reflects brain redistribution, and its use in combination with the umbilical artery in a cerebroplacental ratio seems to improve prediction of adverse outcome, mainly in near-term pregnancies, where most instances of adverse outcome occur in foetuses with normal umbilical artery. Ductus venosus Doppler waveform is a surrogate parameter of the foetal acid-base status. However, the benefits of its use in the management of early-onset growth restriction needs further evidence.

Fetal aortic isthmus blood flow and the fraction of cardiac output distributed to the upper body and brain at 11-20 weeks of gestation

OBJECTIVE

To measure serial changes in fetal aortic isthmus (AI) blood flow and estimate the fraction of fetal cardiac output distributed to the upper body, including the brain, at 11-20 weeks of gestation.

METHODS

Using pulsed-wave Doppler and two-dimensional ultrasound, blood flow velocities and inner diameter of the AI, aortic valve (AV) and pulmonary valve (PV) were measured longitudinally in 143 fetuses and volume blood flows (Q) were calculated for each site using the formula: Q (mL/min) = pix (diameter/2)(2) x velocity time integral x heart rate x 60. The sum of Q(av) and Q(pv) constituted the combined cardiac output (CCO) and the fraction (%) of the upper body (including brain) blood flow was calculated as: (Q(av)-Q(ai))x100/CCO.

RESULTS

AI blood velocities as well as the vessel diameter increased with advancing gestation, resulting in a significant increase in Q(ai) from 1.9 to 40.5 mL/min during weeks 11 to 20. The AI peak systolic velocity increased from 29 to 63 cm/s, end-diastolic velocity from 1.2 to 5.2 cm/s, and the time-averaged maximum velocity from 11 to 22 cm/s, resulting in a fairly stable pulsatility index (PI) of 2.4-2.6 and resistance index (RI) of 0.91-0.94. On average, 75% of blood ejected by the left ventricle (which represented about 35% of the CCO) passed through the AI to the descending aorta. The fraction of CCO distributed to the upper body, including the brain, was estimated as approximately 13%.

CONCLUSION

We have established longitudinal reference ranges for fetal AI diameter, blood flow velocities, PI, RI and volume blood flow at 11-20 weeks of gestation. The human fetus appears to direct a relatively small fraction (13%) of its CCO to the upper body, including the brain, during this period of pregnancy.

Monitoring of fetuses with intrauterine growth restriction: longitudinal changes in ductus venosus and aortic isthmus flow

OBJECTIVES

To explore in growth-restricted fetuses the sequence of changes in aortic isthmus and ductus venosus blood flow in relation to other arterial Doppler parameters commonly used to evaluate fetal wellbeing.

METHODS

Umbilical and middle cerebral arteries, ductus venosus and aortic isthmus were explored serially by means of pulsed Doppler in a cohort of singleton small-for-gestational age fetuses requiring delivery before 34 weeks. Longitudinal changes in the last 30 days before delivery were modeled by multilevel analysis. Individual regression lines for each variable were calculated for each fetus and from these the regression lines for the whole group were derived, in order to estimate the mean time point at which each Doppler parameter became abnormal (outside the 5th-95th centile range). A survival analysis was performed during the monitoring period, in which the endpoint was an abnormal Doppler pulsatility index.

RESULTS

A total of 162 observations were performed on 46 fetuses (median, 3; range, 2-10). The median gestational age at inclusion was 28.9 (range, 23.6-33.4) weeks and delivery occurred at a median gestational age of 30.5 (range, 25.9-33.9) weeks. Six (13%) cases of perinatal mortality occurred. Umbilical and middle cerebral artery Doppler showed an almost linear deterioration throughout monitoring, becoming abnormal on average 24 days and 20 days before delivery, respectively. Aortic isthmus Doppler became abnormal on average 13 days before delivery, while ductus venosus Doppler did so within the last week before delivery.

CONCLUSIONS

In preterm growth-restricted fetuses, aortic isthmus blood flow becomes abnormal on average 1 week earlier than does that in the ductus venosus. This could provide a sound basis to better define management protocols aimed to improve intact fetal survival.

Relationship between aortic isthmus and ductus venosus velocity waveforms in severe growth restricted fetuses

OBJECTIVE

To evaluate the incidence of abnormalities in velocity waveforms from ductus venosus (DV) and aortic isthmus (AoI) in fetuses with intrauterine growth restriction (IUGR) and their reciprocal temporal relationship.

METHODS

DV and AoI velocity waveforms were recorded in 31 IUGR fetuses characterized either by absent end diastolic (20) or reverse flow (11) in umbilical artery. Abnormal velocity waveforms in DV and AoI were defined in presence of reverse diastolic flows.

RESULTS

Abnormal DV velocity waveforms were present in 10 fetuses and were always associated with abnormalities. Abnormal AoI flows were also present in 10 fetuses of the remaining 21 fetuses with normal DV velocity waveforms (47.6%). Longitudinal monitoring of fetuses with normal DV flows showed a significantly shorter time interval in the onset of reverse flow in DV when abnormalities in AoI were present (4 vs 14 days p=0.001) irrespectively of gestational age or other potential confounding variables.

CONCLUSIONS

Our data suggest that AoI velocity waveforms become abnormal at an earlier stage of fetal compromise than DV.

Use of the 3-vessel view to record Doppler velocity waveforms from the aortic isthmus in normally grown and growth-restricted fetuses: comparison with the long aortic arch view

OBJECTIVE

Aortic isthmus (AoI) velocity waveforms are considered powerful indicators of hemodynamic deterioration in intrauterine growth-restricted (IUGR) fetuses. However, technical difficulties in sampling AoI velocity waveforms from the longitudinal aortic arch (LAA) have limited its clinical application thus far. In this study, we tested the possibility of recording AoI velocity waveforms from the 3-vessel (3V) view of the fetal mediastinum and comparing the agreement of these measurements with recordings from the LAA.

METHODS

Doppler measurements of the pulsatility index (PI) from the AoI were performed in 70 fetuses (20 IUGR and 50 normally grown) between 20 and 34 weeks' gestation. All measurements were sampled in both the LAA and 3V views by the same investigator. Reliability was evaluated with intraclass correlation coefficients (ICCs), and Bland-Altman plots were generated. The time required to complete the measurements was compared.

RESULTS

A high degree of reliability was observed between PI values obtained from LAA and 3V views in both IUGR and normally grown fetuses (all fetuses: ICC, 0.976; 95% confidence interval [CI], 0.961-0.985; normally grown: ICC, 0.839; 95% CI, 0.731-0.906; IUGR: ICC, 0.954; 95% CI, 0.886-0.982). However, recordings from the 3V view were significantly less time-consuming than those from the LLA view (mean +/- SD, 30.4 +/- 14.2 versus 52.8 +/- 29.4 seconds; P < .0001) and showed higher intraobserver reproducibility.

CONCLUSIONS

In IUGR and normally grown fetuses, AoI waveforms can be reliably obtained from the 3V view with higher reproducibility and a shorter recording time.

Postpartum ovarian vein thrombosis after cesarean delivery: a case report

Introduction

Postpartum ovarian vein thrombosis is an uncommon complication; incidence varies between 0.002% and 0.05%. It most often occurs during the 2–15 days following delivery.

Case presentation

A 22-year-old pregnant woman at term presented to hospital with uterine contractions, abdominal pain, nausea and vomiting. After delivery an ovarian vein thrombosis was diagnosed.

Conclusion

Low-molecular weight heparin with broad-spectrum antibiotics are the accepted therapy in non-complicated cases of postpartum ovarian vein thrombosis.