Fetal Blood Flow Redistribution Research Articles

T2* weighted fetal MRI and the correlation with placental dysfunction

IntroductionTransverse relaxation time (T2*) is related to tissue oxygenation and morphology. We aimed to describe T2* weighted MRI in selected fetal organs in normal pregnancies, and to investigate the correlation between fetal organ T2* and placental T2*, birthweight (BW) deviation, and redistribution of fetal blood flow. MethodsT2*-weighted MRI was performed in 126 singleton pregnancies between 23+6- and 41+3-weeks’ gestation. The T2* value was obtained from the placenta and fetal organs (brain, lungs, heart, liver, kidneys, and spleen). In normal BW pregnancies (BW > 10th centile), the correlation between the T2* value and gestational age (GA) at MRI was estimated by linear regression. The correlation between fetal organ Z-score and BW group was demonstrated by boxplots and investigated by analysis of variance (ANOVA) for each organ. ResultsIn normal BW pregnancies fetal organ T2* was negatively correlated with GA. We found a significant correlation between BW group and fetal organ T2* z-score in the fetal heart, kidney, lung and spleen. A positive linear correlation was demonstrated between fetal organ T2* and outcomes related to placental function such as BW deviation and placenta T2* in all investigated fetal organs except for the fetal liver. In the fetal heart, kidneys, and spleen the T2* value showed a significant correlation with fetal redistribution of blood flow (Middle cerebral artery Pulsatility Index) before delivery. DiscussionFetal T2* is correlated with BW, placental function, and redistribution of fetal blood flow, suggesting that fetal organ T2* reflects fetal oxygenation and morphological changes related to placental dysfunction.

Late-term fetuses with reduced umbilical vein blood flow volume: An under-recognized population at increased risk of growth restriction

ObjectivesTo investigate the umbilical vein and uterine arteries blood flow volume (UV-Q, UtA-Q) in late-term pregnancies. Study designThis was a prospective observational cohort study of singleton pregnancies ≥40 + 0 weeks in which UV-Q and UtA-Q, both absolute and normalized for estimated fetal weight (EFW) values, were evaluated in relation to AC drop of ≥20 percentiles from 20 weeks to term, Doppler signs of fetal cerebral blood flow redistribution and composite adverse perinatal outcome. The presence of neonatal hypoglycaemia and the need of formula milk supplementation were also examined. ResultsThe study population comprised 200 women. Fetuses with AC drop (n = 34) had a significantly lower UV-Q and UV-Q/EFW than fetuses without AC drop (n = 166): median UV-Q 184 ml/min (IQR 143–225) vs 233 ml/min (IQR 181–277), p = 0.0006; median UV-Q/EFW 55 ml/min/kg (IQR 42–66) vs 63 ml/min/kg (IQR 48–74), p = 0.03. Fetuses with cerebral blood flow redistribution (n = 48) had a significantly lower UV-Q and UV-Q/EFW than those without (n = 134): median UV-Q 210 ml/min (IQR 155–263) vs 236 ml/min (IQR 184–278), p = 0.04; median UV-Q/EFV 58 ml/min/kg (IQR 45–70) vs 65 ml/min/kg (IQR 50–76), p = 0.04. There was a significant moderate correlation between middle cerebral artery pulsatility index (MCA-PI) and UV-Q and UV-Q/EFW (Spearman Rho −0.20 and −0.20; p = 0.008 and p = 0.006). ConclusionsThe umbilical vein blood flow volume might have a potential role to identify fetuses with stunted growth in late-term pregnancies.

A Study of Fetal Umbilical Artery and Middle Cerebral Artery Doppler Velocimetry Before and after Treatment of Severe Maternal Iron Deficiency Anaemia

Background: Despite maternal iron deficiency anemia being a worldwide medical complication, very few studies have been performed to evaluate the efficacy of iron supplementations for treating and preventing adverse pregnancy sequelae. This study attempts to show the impact of maternal iron deficiency anemia on the mother and the fetus and whether treatment can reverse the physiological and pathological effects of anemia on the mother as well as the fetus. Objective: To evaluate the effect of vascular adaptation and extent of compensatory changes in the fetus with the change in maternal hemoglobin (Hb) levels and to study maternal and perinatal outcomes after treatment of maternal iron deficiency anemia. Methodology: The present study was an observational prospective study conducted on 50 pregnant women in GMC, Srinagar from January 2016 to June 2017. The study population was divided into two groups-Group A-Patients with moderate anemia – Hb 7–9 g/dl and Group B-Patients with severe anemia – Hb <7 g/dl. Group A received parenteral iron preparation and Group B received blood transfusion or packed red blood cells until Hb exceeded 7 g/dL, then parenteral iron was used. Maternal Hb and color Doppler were performed before and after treatment of anemia. Results: There was a decrease in the umbilical artery resistivity index (RI) after treatment of maternal anemia in both the groups and the decrease was more in those who received blood transfusion. There was an improvement in middle cerebral artery RI in both the groups after treatment and the increase was statistically significant. The C/U ratio was normalized to >1.1 in both the study groups after treatment of anemia. Conclusion: Our data support the fact that maternal Hb content of <7 g/dl is strongly associated with marked fetal hemodynamic adaptation and must be treated with acute red cell transfusion. Moderate anemia (>7 g/dl) is not sufficient to trigger fetal blood flow redistribution and can be treated with parenteral iron. Close monitoring of the fetal umbilical and cerebral circulation by Doppler examination in anemic pregnancies allows the measurement of the amplitude of fetal vascular response, early assessment of fetal damage and helps in improving fetal outcome as well.

OC04.02: Fetal growth rate and cerebral blood flow redistribution in suspected late fetal growth restriction

OC04.02: Fetal growth rate and cerebral blood flow redistribution in suspected late fetal growth restriction

Ultrasound Measurements of Intracranial Structures in Growth-Restricted Neonates with Fetal Blood Flow Redistribution: A Pilot Observational Study

Background: Fetal growth restriction (FGR) is associated with neonatal and long-term neuro-morbidity. Preferential redistribution of blood flow to the brain is a common antenatal adaptation in FGR. The impact of this “brain sparing,” which may signify severity of FGR, on the growth of brain structures has not been studied. Aim: To compare corpus callosum (CC), cerebellar, and ventricular measurements of FGR neonates with evidence of fetal blood flow redistribution with those of gestation-matched appropriately grown (AGA) neonates. Methods: This was a pilot, prospective observational study conducted at a tertiary level neonatal unit in Melbourne, Australia. Cranial ultrasound was done between days 1 and 3 of life in FGR and AGA neonates. Results: Cranial ultrasound on 20 FGR, gestation (mean ± SD) 31.4 ± 3.1 weeks, weight 1,205 ± 463 g, and 20 AGA neonates, 31.1 ± 3.0 weeks, 1,668 ± 490 g, was performed. CC length was significantly decreased in FGR neonates as compared to AGA neonates (35.28 ± 3.47 vs. 38.83 ± 4.05 mm, p = 0.0002). CC was significantly thinner at genu (3.36 ± 0.66 vs. 4.04 ± 0.83 mm, p = 0.007), body (1.97 ± 0.36 vs. 2.27 ± 0.39 mm, p = 0.02), and splenium (4.07 ± 0.76 vs. 4.72 ± 0.75 mm, p = 0.003) in FGR vs. AGA neonates. CC-fastigium length was also significantly decreased (39.65 ± 3.87 vs. 41.96 ± 4.50 mm, p = 0.04). Similarly, FGR neonates showed decreased transverse cerebellar diameter (36.15 ± 5.51 vs. 38.81 ± 7.21 mm, p = 0.02), but ventricular measurements were comparable. In multivariate analysis, these differences were evident independent of the birth weight. Conclusions:CC and cerebellar measurements are significantly smaller in FGR neonates with fetal blood flow redistribution, which warrants further study.

Third-trimester Reference Ranges for Cerebroplacental Ratio and Pulsatility Index for Middle Cerebral Artery and Umbilical Artery in Normal-growth Singleton Fetuses in the Israeli Population.

BackgroundThe ratio between the fetal umbilical artery pulsatility index (UA-PI) and the middle cerebral artery pulsatility index (MCA-PI) is termed the cerebroplacental ratio (CPR). The CPR represents fetal blood flow redistribution at the early stages of placental insufficiency; moreover, it has predictive value for adverse intrapartum and neonatal outcomes. However, internationally accepted reference ranges for CPR are lacking.ObjectiveThis study sought to establish UA-PI, MCA-PI, and CPR reference ranges in low-risk, normal-growth singleton fetuses during the third trimester of pregnancy.MethodsA retrospective cohort cross-sectional study was performed in the obstetrics ultrasound unit of a university hospital in Israel. We reviewed all fetal and maternal electronic records of pregnant women referred for ultrasound assessment during the third trimester between January 2014 and January 2019. We included only singleton pregnancies with normal anatomy scans and a normal third-trimester estimated fetal weight. The UA-PI, MCA-PI, and CPR reference ranges were reconstructed for each of the vessels for each gestational age between 29 and 41 weeks.ResultsA total of 560 pregnancies met the inclusion criteria. Satisfactory waveforms and measurements were obtained in all cases. At least 18 women enrolled at each gestational week. The MCA-PI and CPR values showed a similar parabolic curve during the third trimester of pregnancy, with a peak value at 32 and 33 gestational weeks, respectively. The UA-PI showed a linear and gradual decrease over the gestational age.ConclusionsIn this study we established UA-PI, MCA-PI, and CPR reference ranges in low-risk, normal-growth singleton fetuses during the third trimester based on the Israeli population.

Third Trimester Fetal Cardiac Blood Flow and Cardiac Outcomes in School-Age Children Assessed By Magnetic Resonance Imaging.

BackgroundAn adverse fetal environment leads to fetal hemodynamic adaptations with cardiac flow alterations that may subsequently affect cardiac development. We examined the associations of third trimester placental and fetal cardiac hemodynamics with cardiac outcomes in school‐age children.Methods and ResultsWe performed a population‐based prospective cohort study among 547 mothers and their children. At a gestational age of 30.4 (95% range 28.4–32.7) weeks, we measured umbilical and cerebral artery resistance, cardiac output, and tricuspid and mitral E/A waves with Doppler. At the median age of 10.0 years (95% range 9.4–11.7) we measured cardiac outcomes with cardiac magnetic resonance imaging. Cardiac outcomes included right ventricular end‐diastolic volume) and right ventricular ejection fraction, left ventricular end diastolic volume and left ventricular ejection fraction, left ventricular mass, and left ventricular mass‐to‐volume ratio as left ventricular mass/left ventricular end diastolic volume. Higher third‐trimester umbilical artery resistance was associated with higher childhood right ventricular ejection fraction (P value <0.05), but not with other cardiac outcomes. The third‐trimester umbilical artery‐cerebral artery pulsatility index ratio was not associated with childhood cardiac outcomes. Higher third‐trimester fetal left cardiac output was associated with lower childhood left ventricular ejection fraction and higher left ventricular mass‐to‐volume ratio (P value <0.05). Third‐trimester fetal right cardiac output was not associated with childhood cardiac outcomes. A higher third‐trimester fetal tricuspid valve E/A ratio was associated with higher childhood right ventricular ejection fraction (P value <0.05).ConclusionsOur findings suggest that fetal cardiac fetal blood flow redistribution may have long‐term effects on cardiac structure and function. These results should be considered as hypothesis generating and need further replication.

Fetal umbilical, cerebral and pulmonary blood flow patterns in relation to lung function and asthma in childhood. The Generation R Study.

BackgroundFetal growth restriction is associated with higher risks of childhood respiratory morbidity. Fetal blood flow adaptations might contribute to these associations. We examined the associations of fetal umbilical, cerebral, and pulmonary blood flow with wheezing patterns, lung function, and asthma in childhood.MethodsIn a population‐based prospective cohort study among 903 children, we measured fetal umbilical, cerebral, and pulmonary blood flow by pulsed‐wave Doppler at a median gestational age of 30.3 (95% range 28.8‐32.3) weeks. We obtained information about wheezing patterns until the age of 6 years by questionnaires. Lung function was measured by spirometry and information about current asthma was obtained by questionnaire at the age of 10 years.ResultsResults showed a non‐significant relationship between a higher umbilical artery pulsatility index (PI) and umbilical artery PI/cerebral artery PI ratio, indicating fetal blood flow redistribution at the expense of the trunk, with higher risks of early wheezing (OR [95% CI]: 2.07 (0.70‐6.10) and 2.74 (0.60, 12.62) per unit increase, respectively). A higher pulmonary artery time velocity integral, indicating higher pulmonary vascular resistance, was associated with a higher risk of late/persistent wheezing (Z‐score 1.14 [1.01‐1.29]). A higher middle cerebral artery PI was associated with a higher FEV1/FVC (Z‐score [95% CI]: 0.21 [0.01‐0.42]). Results did not materially change after additional adjustment for birth and growth characteristics.ConclusionThird‐trimester fetal blood flow patterns might be related to childhood respiratory health. These findings should be considered as hypothesis generating and need further replication.

Effect of maternal anemia on fetal Doppler indices during the last trimester of pregnancy

Background: Anemia is one of the most commonly encountered medical disorders during pregnancy. In developing countries it is a cause of serious concern as, besides many other adverse effects on the mother and the fetus it contributes significantly to high maternal mortality. According to United Nation declaration 1997, anemia is a major public health problem that needs total elimination. It is estimated that globally two billion people suffer from anemia or iron deficiency.Maternal anemia is frequently associated with premature delivery, reduced neonatal weight, infant iron deficiency, neonatal death, and low APGAR scores at 1 min. It is also suspected to reduce the oxygen supply to the growing fetus, leading to the redistribution of fetal blood flow. Objective: The aim of this study was to evaluate the effect of maternal anemia on fetal Doppler indices namely umbilical artery and middle cerebral artery in the last trimester of pregnancy. Patients and Methods: This study was designed as a prospective case control clinical trial carried out in Obstetric outpatient clinics and inpatient ward, Ain Shams University Maternity Hospital on 200 patients. The patients must follow these criteria, gestational age between 28-40 weeks of singleton pregnancy (calculated by their last menstrual period or by earlier ultrasound), fetus is alive and normal fetal ultrasound parameters. Results: The umbilical artery resistance index show a significant increase in moderate severe anemic patients more than control group, umbilical artery pulsatility index show a significant increase in severe anemic group more than the other 3 groups, umbilical artery systolic/diastolic ratio show a significant increase in severe anemic more than the other groups. Finally the umbilical artery cerebral/umbilical artery resistance ratio show a significant increase in severe anemic more than the other groups. Conclusion: GA at delivery in in different groups was matched. i.e. there was no statistical significant difference between different studied groups regarding GA at delivery (P > 0.05). Neonatal ICU admission were 2(4%), 2(4%), 4(8%) and 9(18%) in different groups respectively. There was statistical significant difference between different studied groups regarding Neonatal ICU admission (P < 0.05).

Effect of Maternal Anemia on Fetal Doppler Indices during the Last Trimester of Pregnancy

Background: Anemia is one of the most commonly encountered medical disorders during pregnancy. In developing countries it is a cause of serious concern as, besides many other adverse effects on the mother and the fetus it contributes significantly to high maternal mortality. According to United Nation declaration 1997, anemia is a major public health problem that needs total elimination. It is estimated that globally two billion people suffer from anemia or iron deficiency.Maternal anemia is frequently associated with premature delivery, reduced neonatal weight, infant iron deficiency, neonatal death, and low APGAR scores at 1 min. It is also suspected to reduce the oxygen supply to the growing fetus, leading to the redistribution of fetal blood flow. Objective: The aim of this study was to evaluate the effect of maternal anemia on fetal Doppler indices namely umbilical artery and middle cerebral artery in the last trimester of pregnancy. Patients and Methods: This study was designed as a prospective case control clinical trial carried out in Obstetric outpatient clinics and inpatient ward, Ain Shams University Maternity Hospital on 200 patients. The patients must follow these criteria, gestational age between 28-40 weeks of singleton pregnancy (calculated by their last menstrual period or by earlier ultrasound), fetus is alive and normal fetal ultrasound parameters. Results: The umbilical artery resistance index show a significant increase in moderate severe anemic patients more than control group, umbilical artery pulsatility index show a significant increase in severe anemic group more than the other 3 groups, umbilical artery systolic/diastolic ratio show a significant increase in severe anemic more than the other groups. Finally the umbilical artery cerebral/umbilical artery resistance ratio show a significant increase in severe anemic more than the other groups. Conclusion: GA at delivery in in different groups was matched. i.e. there was no statistical significant difference between different studied groups regarding GA at delivery (P > 0.05). Neonatal ICU admission were 2(4%), 2(4%), 4(8%) and 9(18%) in different groups respectively. There was statistical significant difference between different studied groups regarding Neonatal ICU admission (P < 0.05).

Influence of fetal blood flow redistribution on fetal and childhood growth and fat distribution: the Generation R Study.

A suboptimal intrauterine environment leads to fetal blood flow redistribution and fetal growth restriction. Not much is known about childhood growth consequences. We examined the associations of fetal blood flow redistribution with birth outcomes, and repeatedly measured fetal and childhood growth and fat mass measures. Prospective cohort study. Population-based. One thousand one hundred and ninety-five pregnant women and their children. We measured umbilical and cerebral artery blood flow at a gestational age of 30.3 weeks (95% range, 28.5-32.6 weeks). A higher umbilical/cerebral (U/C) pulsatility index ratio is an indicator of preferential blood flow to the brain cerebral circulation at the expense of the lower body parts. Fetal and childhood growth were repeatedly measured from the third trimester until childhood. We measured the total body fat mass, lean fat mass and android/gynoid fat mass ratio by dual-energy X-ray absorptiometry and preperitoneal fat by ultrasound at 6 years. A higher fetal U/C ratio was associated with increased risks of preterm birth and small size for gestational age at birth [odds ratios, 1.41 (95% confidence interval, 1.08-1.85) and 1.63 (95% confidence interval, 1.21-2.19), respectively, per SDS increase in U/C ratio]. Longitudinal growth analyses showed that a higher fetal U/C ratio was associated with persistently lower head circumference, length and weight from third trimester fetal life until childhood (all P < 0.05). The fetal U/C ratio was not associated with total body and abdominal fat measures at 6 years. Our results suggest that fetal blood flow redistribution affects fetal development and has persistent consequences for childhood growth. Fetal blood flow redistribution affects fetal development and has persistent consequences for childhood growth.

O-029 Neonatal Circulation Measured Using Near-infrared Spectroscopy (nirs) Differs Between Preterm And Term Born Intrauterine Growth Restricted (iugr) Infants

<h3>Background and aim</h3> IUGR fetuses display redistribution of fetal blood flow to vital organs. This can be different in preterm and term IUGR fetuses. It is not known whether the distribution of the neonatal circulation is still affected by IUGR, and if it differs between these groups. Our aim was to compare the neonatal circulation in preterm and term IUGR infants, measured by NIRS. <h3>Methods</h3> Preterm and term infants were prospectively included between May 2012 and April 2014 when IUGR was diagnosed. Cerebral, renal and abdominal regional tissue oxygen saturations (rSO₂) were measured for 2 h continuously using NIRS on days 1 to 3 after birth. Fractional tissue oxygen extraction (FTOE) was calculated using rSO₂ and arterial oxygen saturation (SaO₂) values: (SaO₂–rSO₂)/SaO₂. <h3>Results</h3> We included 42 IUGR infants (21 preterm/21 term), gestational age median 31.3 weeks (IQR 28.5–33.2), and 38.6 weeks (37.7–39.1), respectively; birth weight 1100 grams (770–1510), and 2420 grams (2027–2645). Results are shown in Table 1. <h3>Conclusion</h3> In the first 2 days after birth, preterm IUGR infants showed lower renal and abdominal rSO₂ (higher FTOE) when compared with term IUGR infants, indicating altered neonatal circulation. Furthermore, cerebral rSO₂was higher and cerebral FTOE was lower indicating increased cerebral perfusion. This may be interpreted as brain sparing continuing after birth. However, the difference with term IUGR (higher cerebral FTOE indicating no brain sparing) vanishes. We conclude that preterm IUGR infants experience brain sparing in the first 2 days, whereas term IUGR infants do not.

Changes in fetal Doppler indices as a marker of failure to reach growth potential at term

To evaluate whether changes in the middle cerebral artery (MCA), umbilical artery (UA) and cerebroplacental ratio (CPR) Doppler indices at term might be used to identify those appropriate-for-gestational-age (AGA) fetuses that are failing to reach their growth potential (FRGP). This was a retrospective cohort study of data obtained in a single tertiary referral center over a 10-year period from 2002 to 2012. The UA pulsatility index (PI), MCA-PI and CPR were recorded between 37+0 and 41+6 weeks within 14 days before delivery. The Doppler parameters were converted into multiples of the median (MoM), adjusting for gestational age, and their correlation with birth-weight (BW) centiles was evaluated by means of regression analysis. Doppler indices were also grouped according to BW quartiles and compared using Kruskal-Wallis and Dunn's post-hoc tests. The study included 11576 term fetuses, with 8645 (74.7%) classified as AGA. Within the AGA group, fetuses with lower BW had significantly higher UA-PI, lower MCA-PI and lower CPR MoM values. Large-for-gestational-age (LGA) fetuses were considered as the group least likely to be growth-restricted. The CPR MoM < 5(th) centile (0.6765 MoM) in these fetuses was used as a threshold for diagnosing FRGP. Using this definition, in the AGA pregnancies the percentage of fetuses with FRGP was 1% in the 75-90(th) BW centile group, 1.7% in the 50-75(th) centile group, 2.9% in the 25-50(th) centile group and 6.7% in the 10-25(th) centile group. AGA pregnancies may present with fetal cerebral and placental blood flow redistribution indicative of fetal hypoxemia. Fetal Doppler assessment may be of value in detecting AGA pregnancies that are subject to placental insufficiency, fetal hypoxemia and FRGP. Future studies are needed to evaluate the appropriate threshold for the diagnosis of FRGP and the diagnostic performance of this new approach for the management of growth disorders.

Fetal circulatory variation in an acute incident causing bradycardia.

Umbilical artery\\vein, middle cerebral artery, and ductus venosus Doppler velocimetry were performed at 33 weeks of gestation in the settings of an intrauterine growth restricted fetus during a heart rate deceleration. Interestingly, we recorded a sudden onset redistribution of fetal blood flow with fetal bradycardia. Spontaneous normalization of waveforms was observed once fetal heart rate returned to normal. Our case provides evidence to circulatory variation of a human fetus resulting from an acute incident causing bradycardia.

Distended azygos and hemiazygos vein without interrupted inferior vena cava in a case of agenesis of the ductus venosus

A 26-year-old woman, gravida 2 para 0, was referred for a detailed scan including uterine artery Doppler ultrasound examination, as her previous pregnancy ended in the intrauterine death of twins. Uteroplacental resistance in the index pregnancy was markedly increased with bilateral notching of the uterine artery waveform. At 26 weeks detailed fetal echocardiography showed normal cardiac structures. However, a blood vessel with venous flow velocity waveforms running in parallel to the thoracic aorta, which was classified as a distended azygos vein, was detected by color Doppler ultrasound imaging (Figure 1). The possibility of a heterotaxy syndrome could be excluded due to situs solitus and a non-interrupted inferior vena cava (IVC) (Figures 2-4). Furthermore, abnormal draining of the umbilical vein (UV) directly into the abdominal part of the IVC was detected (Figures 3 and 4). This was classified as agenesis of the ductus venosus (DV) with portocaval shunt, and was similar to that described in a recently published case1, 2. Posterior to this connection a collateral venous vessel originated from the IVC, joining the dilated hemiazygos vein on the left side of the abdominal aorta. In the thorax the hemiazygos vein crossed to the right, joining the azygos vein (Figure 5), before finally running into the superior vena cava. Color Doppler ultrasound examination showing distended azygos vein (red) posterior to the thoracic aorta (blue). Ultrasound scan showing normal four-chamber view and cross-section through the thoracic aorta and azygos vein. Gray-scale ultrasound image showing direct connection of the umbilical vein to the inferior vena cava. Color Doppler image with glass-body rendering, showing connection of the umbilical vein (UV) and the inferior vena cava (IVC). Color Doppler image of the fetal thoracic region, showing the hemiazygos vein crossing from the left to the right side and joining the azygos vein. A possible complication caused by a direct connection between the UV and the IVC may be the development of high-output cardiac failure owing to chronic volume overload of the central venous system and the heart3, 4. However, in our case no signs of cardiac overload were detected. At 31 + 4 weeks the woman developed pre-eclampsia and fetal arterial blood flow redistribution indicated low resistance in the middle cerebral artery. After induction of lung maturity, a boy with a birth weight of 1550 g, Apgar scores of 7, 9 and 9 at 1, 5 and 10 min, respectively, and arterial pH 7.28 was delivered by Cesarean section. The neonatal course was uneventful. Pediatric echocardiography at the age of 10 weeks showed normal cardiac function, a closed DV and an enlarged hemiazygos vein on the left side of the abdominal aorta. The liver circulation was normal. At the time of writing, the infant was 10 months old and healthy. To our knowledge, this is the first description of a distended azygos/hemiazygos vein coexistent with a non-interrupted IVC and without association with heterotaxy syndrome. The collateral venous circulation through the hemiazygos vein in the presence of an abnormal direct connection between the UV and IVC may have resulted in a protective effect against cardiac overload. However, owing to the development of pre-eclampsia and fetal blood flow redistribution with decreasing resistance in the middle cerebral artery, a Cesarean section was indicated. We would advise longitudinal fetal monitoring with Doppler ultrasound imaging and echocardiography in similar cases. H. Hille*, R. Chaoui , S. Renz , K. Hecher?, * Lappenbergsallee 50, Hamburg, D-20257, Germany, Center for Pediatric Cardiology, Hamburg, Germany, Obstetrics and Fetal Medicine, University Medical Center, Hamburg, Germany, ? Center for Prenatal Diagnosis and Human Genetics, Berlin, Germany

Fetal MRI: what is the future?

Fetal MRI: what is the future?

Fetal ductus venosus, middle cerebral artery and umbilical artery flow responses to uterine contractions in growth‐restricted human pregnancies

To explore fetal ductus venosus (DV) flow velocity changes relative to umbilical artery (UA) blood flow and brain-sparing flow (BSF) during uterine contractions. Forty-five term fetuses suspected of having growth restriction were exposed to an oxytocin challenge test (OCT) with simultaneous Doppler velocimetry in the UA, middle cerebral artery (MCA) and DV. Basal BSF was defined as a MCA-to-UA pulsatility index (PI) ratio of < 1.08, and de novo BSF as a decrease in MCA-PI of > or = 1 SD (equivalent to a value of 0.24 units) during the OCT. Basal DV flow velocities were lower in the BSF group (n = 7) than they were in the non-BSF group (n = 38). During the OCT, DV flow velocity parameters changed in neither group but MCA-PI decreased in the non-BSF group. A crude de novo BSF was not associated with DV flow velocity changes, but when UA-PI changes were considered, a serial relationship was found between decreased UA-PI, increased DV flow velocity, and decreased MCA-PI. When UA-PI increased, the MCA-PI still decreased (though not significantly) but DV flow velocity parameters remained unchanged. Established fetal BSF is associated with low DV flow velocities, but in an acute sequence there might be two contrasting courses along which BSF develops: one with an increase and one with a decrease in the UA vascular flow resistance. In the former situation the DV flow velocity increases, while in the latter situation the role of the DV in the acute redistribution of fetal blood flow is unclear.

Fetal kidney volume and its association with growth and blood flow in fetal life: The Generation R Study

An adverse fetal environment may lead to smaller kidneys and subsequent hypertension with renal disease in adult life. The aim of our study was to examine whether maternal characteristics, fetal growth, fetal blood flow redistribution, or inadequate placental perfusion in different periods of fetal life affect kidney volume in late fetal life. We also determined if fetal kidney volume was linked to the amount of amniotic fluid. In a population-based prospective study from early fetal life, fetal growth characteristics and fetal blood flow parameters were assessed by ultrasound and Doppler examinations in 1215 women in mid- and late-pregnancy. Kidney volume was measured in late pregnancy. Maternal height and pre-pregnancy weight were associated with kidney volume. After adjustment for the same characteristics in late pregnancy, fetal growth and blood flow in mid-pregnancy were not associated with kidney volume in late pregnancy. In late pregnancy, however, all fetal growth parameters were positively linked with kidney volume. The largest effect on kidney volume was found for abdominal circumference. Signs of fetal blood flow redistribution and increased placental resistance were associated with decreased kidney volume in late pregnancy. Amniotic fluid volume was positively associated with kidney volume. Our study shows that maternal anthropometrics, fetal growth, fetal blood flow redistribution, and raised placental resistance all correlate with kidney volume.

Intrauterine Growth Restriction, Brain‐Sparing Effect, and Neurotrophins

Intrauterine growth restriction (IUGR) is failure of the fetus to achieve his or her intrinsic growth potential, due to anatomical/functional diseases or disorders in the feto-placental-maternal unit. Growth restriction successfully balances reduced oxygen delivery and consumption; however, chronic hypoxia is responsible for fetal blood flow redistribution to cardinal organs (brain, myocardium, and adrenal glands), the so-called brain-sparing effect. The neurotrophin family comprises four structurally related molecules: the nerve growth factor (NGF), the brain-derived neurotrophic factor (BDNF), the neurotrophin-3 (NT-3), and the neurotrophin-4 (NT-4). By exerting neuroprotection, neurotrophins are critical for pre- and postnatal brain development. Based on the assumption that the brain-sparing effect might be activated in full-term IUGR infants, we hypothesized that circulating neurotrophin levels should not differ between IUGR and appropriate for gestational age (AGA) infants. Indeed, we found that in both groups, circulating NT-3, NT-4, and BDNF levels do not differ, and this finding could possibly be attributed to the activation of the brain-sparing effect. In contrast, NGF levels were higher in the AGA compared to the IUGR group. However, only NGF levels positively correlated with the customized centile and the birth weight of the infants, and both of them were lower in the IUGR group.

Magnesium sulfate exposure increases fetal blood flow redistribution to the brain during acute non-acidemic hypoxemia in goats

Background It is still controversial that intrapartum exposure to magnesium may or may not reduce brain damage in premature infants in human and animal models. Aims We investigated the effect of hypoxemia alone under magnesium exposure on fetal cardiovascular changes in chronically catheterized goat fetuses. Study design We performed a 3-day experimental protocol with control (10% glucose) on day 1, recovery on day 2, and magnesium on day 3. Magnesium sulfate was directly infused to fetuses in a bolus dose of 270 mg/kg followed by 80 mg/kg/h. Hypoxemia was induced by maternal inhalation of nitrogen gas on day 1 and on day 3. Cerebral blood flow was measured by colored microsphere techniques. Repeated measure ANOVA and Bonferroni's/Dunn's test were used for comparison. Subjects Six Japanese Saanen goats at 0.85 gestation. Outcome measures Fetal heart rate, blood pressure, and cerebral blood flow. Results Ionized magnesium concentrations were significantly increased. Fetal PO 2 decreased significantly from 30 mmHg to 14 mmHg without acidemia. Magnesium exposure significantly attenuated hypoxemia-induced bradycardia but did not affect blood pressure. Hypoxemia significantly increased fetal brain blood flow from the pre-hypoxic levels on day 1. Magnesium exposure further increased hypoxemia-induced brain blood flow on day 3, but statistical significance was limited to the cerebral cortex. Conclusion In near-term, initially healthy goat fetuses, brain blood flow during acute hypoxemia was significantly increased with magnesium sulfate exposure.