Placental Blood Flow Research Articles

The placenta: A site of end-organ damage after Fontan operation. A case series

BackgroundPlacental insufficiency may be the cause of the high preterm birth rate in women after Fontan operation. In this study we reviewed the clinical course and pregnancy outcome of women with Fontan physiology with a focus on placental pathology. MethodsWe reviewed clinical charts and placental pathology from 7 women with Fontan physiology who had pregnancies at Mayo Clinic, Rochester, Minnesota. The review was limited to cases where placental pathologic specimens were rigorously examined. ResultsSeven women had 13 deliveries between 2002 and 2018. Only 2 of 13 deliveries were at term (>37 weeks). Mean maternal age at time of last delivery was 27.5 ± 3.2 years. Preeclampsia was noted during 2 pregnancies and 2 women had preterm premature rupture of membranes at 24 and 35 weeks gestation, respectively. Placental abruption with bleeding occurred in 2 pregnancies. An additional 4 pregnancies were complicated by intrauterine growth restriction (IUGR). Median placental weight was 441.5 g (IQR 305.5–622.5 g). Median placental weight percentile for gestational age was 10th to 25th, but varied greatly; two placentas were <10th percentile and 5 were >90th percentile for gestational age. Two umbilical cords contained a single umbilical artery. Prominent subchorionic fibrin deposition was a consistent feature in all placentas. Villous hypermaturity was noted in 4 placentas. ConclusionsFontan physiology may be associated with poor placental health. High systemic venous pressure and low cardiac output may contribute to stagnation of placental blood flow and result in subchorionic fibrin deposition and variable villous hypoplasia. This may explain the high preterm birth rate in women with Fontan physiology. Preterm deliveries and small-for-gestational-age (SGA) newborns should be anticipated in this patient population. Analysis of placental pathology may help determine both candidacy for future pregnancy and long-term effects of pregnancy for women with Fontan physiology.

Non-invasive assessment of placental perfusion in vivo using arterial spin labeling (ASL) MRI: A preclinical study in rats

IntroductionNon-invasive assessment of placental perfusion is of great interest to characterize placental function in clinical practice. This article proposes a strictly non-invasive MRI technique using ASL to quantify placental blood flow in vivo. The aim of this study was to develop a fMRI tool to quantify placental blood flow (PBF) in rat, by using arterial spin labeling (ASL) MRI at 4.7 T. Materials and methodsMRI was performed with a dedicated magnet for small animals, in pregnant rats on day 20 of the 22-day gestation period. A Look-Locker flow-sensitive alternating inversion recovery gradient echo sequence was developed as ASL technique (TE: 1.55 ms; TR: 3.5 ms, TI: 56 ms, deltaTI: 56 ms, FA: 20°, Matrix: 128 × 128, 8 segments, 4 Nex). Labeling was performed with global and slice-selective inversions, and T1 map was obtained for each mode of inversion. PBF was then derived from a compartmental model of the variation of T1 between global and slice-selective inversions. ResultsThe full protocol was completed and ASL image post-processing was successful in 18 rats. Forty-seven placentas were analyzed, with a mean PBF of 147 ± 70 ml/min/100 g of placenta, consistent with published values of placental perfusion using invasive techniques. ConclusionASL MRI is feasible for the quantification of PBF in rats at 4.7 T. This technique, which requires no administration of contrast media, could have implications for non-invasive longitudinal and in vivo animal studies and may be useful for the management of human pregnancies.

Developmental onset of cardiovascular disease-Could the proof be in the placenta?

The Barker Hypothesis states change to the maternal environment may have significant impacts on fetal development, setting the stage for adult disease to occur. The development of the maternofetal vasculature during implantation and maintenance during pregnancy is extremely precise, yet dynamic. Delays or dysfunction in the orchestration of anatomical remodeling, maintenance of blood pressure, or responsiveness to metabolic demand may have severe consequences to the developing fetus. While these intermissions may not be fatal to the developing fetus, an interruption, reduction, or an inability to meet fetal demand of blood flow during crucial stages of development may predispose young to disease later in life. Maternal inability to meet fetal demand can be attributed to improper placental development and vascular support through morphological change or physiological function will significantly limit nutrient delivery and waste exchange to the developing fetus. Therefore, we present an overview of the uteroplacental vascular network, maternal cardiovascular adaptations that occur during pregnancy, placental blood flow, and common maternal comorbidities and/or exposures that may perturb maternal homeostasis and affect fetal development. Overall, we examine uterine microvasculature pathophysiology contributing to a hostile gestational environment and fetal predisposition to disease as it relates to the Barker Hypothesis.

Validation studies of a fluorescent method to measure placental glucose transport in mice

IntroductionProper placental function is essential for optimal fetal growth in utero. Placental transfer of nutrients to the fetus can be measured using radiolabelled tracers, but non-radioactive methods have potential advantages. This study aimed to develop a fluorescence-based method to measure placental glucose transport in mice. MethodsTime course and localisation of the IRDye 800CW 2-deoxyglucose were recorded (Lumina IVIS Live Imaging System) following tail vein injection into anaesthetised late pregnant mice. Fluorescent signals in placental and fetal tissues were assessed after injecting conscious dams with 10 nmol IRDye 800CW 2-deoxyglucose (3, 30, 60, 120 min) or vehicle. Specificity of dye uptake was determined by comparing uptake of IRDye 800CW conjugated to 2-deoxyglucose or carboxylate, at 2 and 24 h. Finally, we assessed relationships of fetal size and umbilical blood flow velocities with relative dye uptake. ResultsIn late pregnant mice, uterine fluorescent signal localised rapidly over placentas and remained consistent for >1 h. Signal intensity in whole and homogenised tissues increased in fetuses and decreased in placentas after 3 min and stabilised by 30 min post-injection. Relative fetal dye uptake at 2 and 24 h was greater in littermates with the highest compared to lowest placental efficiency; signals were similar for 2-deoxyglucose- or carboxylate-conjugated dyes. Relative fetal dye uptake correlated positively with fetal weight and placental efficiency and negatively with umbilical artery resistance indices. ConclusionsFetal uptake of IRDye 800CW correlates with markers of placental blood flow and fetal growth, but does not specifically measure placental glucose transport.

Point of care functional cardiac scanning

Patients in the neonatal intensive care often demonstrate clinical situations where hemodynamic compromise is common. Birth itself is the complex transition from placental blood flow to pulmonary blood flow as predominant provider of preload to the left heart, with redirection of blood flow over the foramen ovale and ductus arteriosus. Added pathology such as birth asphyxia, pulmonary hypertension, septic shock, a patent ductus arteriosus, or hypoxia can make it difficult if not impossible for a bedside clinical to estimate a critically ill infants’ blood flow and cardiac function without adding longitudinal measurements of cardiovascular function. The understanding of the need for hemodynamic assessment in the neonatal intensive care setting and the evolution of point of care functional cardiac scanning has led to changing indications for cardiac ultrasounds, now with more emphasis on function instead of structure. With a self-directed training program and supervision, the bedside clinician will be able to provide a detailed assessment of cardiovascular function, shunts and shunt direction, and exclude most structural cardiac abnormalities. By embracing this new skill set, the clinician can target treatments to the actual pathophysiology and monitor response, and adjust treatments if needed, and thus offer advanced care for any sick newborn.

Algorithm of echocardiography in pregnant women

Pregnancy is a physiological condition that takes a defined period of time in a woman’s life. For nine months, the mother’s heart works under conditions of daily additional load, which is necessary to ensure placental blood flow. In this regard, structural and functional adaptation of the heart develops in a healthy woman with a normal pregnancy. A pregnant woman with some heart diseases is less likely to adapt. That leads to greater susceptibility to stress resulting in pathological changes of pregnancy. In addition, each pregnancy may develop new heart diseases, which in some cases may be relatively innocent, but in others — fatal. In this regard echocardiography (EchoCG) is a necessary procedure for assessing a woman’s health status that needs before bearing a fetus, during and after pregnancy.

Three-dimensional power Doppler ultrasound evaluation of placental blood flow in normal monochorionic diamniotic twin pregnancies

BackgroundMonochorionic diamniotic (MCDA) twin pregnancies are at higher risk of adverse outcomes and complications, which are attributed to the influence of placental morphology in MCDA twins. Monitoring of placental function is an important index for clinical decisions. The aim of our study was to evaluate the placental blood flow estimated using three-dimensional power Doppler (3D-PD) ultrasound and the vascular indices distribution with gestational age (GA) in normal MCDA twin pregnancies.MethodsOne hundred four MCDA twin pregnancies and 106 singleton pregnancies (GA range, 14–32 weeks) were included in this prospective study. 3D-PD volume data of each fetus was obtained separately from the placenta at the site of umbilical cord insertion. We analyzed the volume data using sonobiopsy technique. The placental vascularization index (VI), flow index (FI) and vascularizationflow index (VFI), were auto-calculated. The means and standard deviation values of three vascular indices per fetus were calculated and regression analysis of the vascular indices as a function of GA was performed in twin pregnancies. The vascular indices of twin and singleton pregnancies were compared using independent t-test.ResultsThere were no significant differences in VI, FI or VFI among the fetuses of twins (p > 0.05). These vascular indices increased over the course of pregnancy (p < 0.05). We obtained the regression equations for the indices as a function of GA in days: VI = exp. (4.369–28.533/GA) (R2 = 0.699, p < 0.05), FI = exp. (3.916–13.003/GA) (R2 = 0.511, p < 0.05), and VFI = exp. (3.577–37.468/GA) (R2 = 0.675, p < 0.05). There were no significant differences in three vascular indices between MCDA twin and singleton groups (p > 0.05).Conclusions3D-PD placental data using sonobiopsy technique could reflect the placental blood flow of each twin, which could be applied to the study of placental perfusion in MCDA twin pregnancies. This study also presented the vascular indices distribution with GA in normal twin pregnancies, which might be useful for early detection of MCDA complications.

Association between intraoperative phenylephrine administration and umbilical artery pH in women with hypertensive disorders of pregnancy: a retrospective cohort study

In healthy pregnant women undergoing Cesarean section, treatment of post-spinal hypotension (PSH) with phenylephrine is reportedly more efficacious than ephedrine in preventing a decline in umbilical artery pH (UApH), which is an indicator of fetal acidosis. However, phenylephrine has the potential to reduce placental blood flow and consequently decrease UApH in women who develop hypertensive disorders of pregnancy (HDP), due to decreased cardiac function and placental vascular abnormalities. We aimed to verify the association between decreased UApH and phenylephrine administered before delivery to treat PSH in women with HDP. This single-center retrospective cohort study was conducted between April 2008 and October 2016 by assessing the records of pregnant women with confirmed or suspected HDP who underwent Cesarean section under spinal anesthesia. The association between phenylephrine and the primary endpoint of decreased UApH was investigated using logistic regression analysis and propensity score matching. In the original cohort of 107 pregnant women with HDP, neither univariate nor multivariate analysis indicated a significant association between phenylephrine treatment and decreased UApH [crude odds ratio (OR) = 2.26; 95% confidence interval (CI) 0.75-6.77; P = 0.14], (adjusted OR = 1.80; 95% CI 0.55-5.93; P = 0.33). Thirty patients each who were not treated with phenylephrine (control group) and were treated with phenylephrine (phenylephrine group) were matched by propensity score analysis. UApH [median (interquartile range)] was not significantly different between control and phenylephrine groups [7.30 (7.25-7.35) vs. 7.27 (7.25-7.30); P = 0.14]. Intraoperative phenylephrine administration to treat PSH in women with HDP was not associated with decreased UApH.

Diagnostic value of ultrasonic features combined with cesarean section in placenta accrete

Objective To evaluate the diagnostic value of ultrasound image features combined with cesarean section scores for placenta accreta. Methods A total of 151 pregnant women in the later trimester of pregnancy underwent two-dimensional and color Doppler ultrasonography. According to the results of the operation, they were divided into the accreta group and the non-accreta group. The number of cesarean section and placental thickness in the two groups were recorded. The ultrasound image characteristics of the placenta previa, the placenta posterior gap disappeared, the placental lacuna in the placenta, the muscle layer becoming thin or disappeared after the placenta, the anatomical region of the uterus-bladder junction line and the abundant blood flow signal behind the placenta were compared between the two groups. Logistic regression analysis was performed according to the results of single factor analysis. After assigning the characteristics of the regression model, the ROC curve was drawn to determine the best diagnostic intercept point. Results The presence of placenta previa, placental lacuna and placental enriched blood flow signals combined with cesarean section scores were used to diagnose placenta accreta, the area under the ROC curve was 0.991, based the best cut-off point with 4.5, the corresponding diagnostic sensitivity and specificity were 91.1% and 100%, respectively. Conclusions Ultrasound image features combined with cesarean section history scores have a high practical value in the diagnosis of placental accreta. Key words: Ultrasonography, prenatal; Placenta, accreta; Diagnosis

317. Do Calcium channel blockers modulate fetoplacental blood flow? A study using parallel wire myography

Introduction Calcium channel blockers treat maternal hypertension in pregnancy. The effect of newer calcium channel blockers on placental vascular function remains unknown. This study aimed to determine the effect of calcium channel blockers on placental chorionic plate proximal resistance arteries in comparison to maternal omental arteries. Methods Chorionic plate and omental arteries from healthy term pregnancies delivered by caesarean section were studied using parallel wire myography (n = 80; N = 10). Arteries were normalised at 0.9 of L5.1 kPa in 5% O2 and L13.3 kPa in 20% O2 respectively, approximating physiologic vascular pressure and oxygen tension. Arteries were contracted with thromboxane-mimetic U46619 to determine and maintain optimal physiologic vascular tone (EC80). Nifedipine, Nicardipine and Clevidipine were added in incremental doses from 10–10 M to 10–5 M to create dose-dependent relaxation curves. Omental arteries were incubated for 30 min at the highest dose (10–5 M) to further evaluate full effect (n = 16; N = 4). Results Omental arteries demonstrated similar contractility to chorionic plate arteries (8.90 kPa ± 0.681 vs 8.85 kPa ± 0.603). Chorionic plate arteries did not relax with Nifedipine, Nicardipine or Clevidipine (110.73%± 7.518 vs 118.88%±9.379 vs 113.16%±5.163). Omental arteries demonstrated a trend towards larger relaxation with all calcium channel blockers at the highest dose of drug concentration. This was confirmed with highest dose incubation of omental arteries, that showed Nifedipine, Nicardipine and Clevidipine relaxed omental arteries (52.31%±16.294 vs 57.12%±8.621 vs 79.95%±14.862; One-way ANOVA, p Conclusion Chorionic plate arteries demonstrated reduced vasodilatory responses to calcium channel blockers compared to omental arteries. This suggests calcium channel blockers show limited effect on placental blood flow through proximal resistance arteries.

161. Placental development, blood flow and pre-eclampsia; A role for the endometrium?

Placental stress, induced by maternal malperfusion, is believed to be at the epicentre of the pathophysiology of pre-eclampsia, at least for the early-onset sub-type. Deficient remodelling of the spiral arteries has been well documented in the placental bed, with the degree correlating with time of onset of the syndrome. Despite this progress, the cause for the deficiency is still not known. Impaired invasion by the extravillous trophoblast cells essential to the remodelling process has been implicated, as have aberrant interactions between these cells and those of the maternal immune system present in the decidua. Another possibility is that early development of the placenta post-implantation is abnormal, resulting in an impoverished supply of extravillous trophoblast cells. Although this hypothesis has received little attention to date, recent transcriptional analyses have revealed abnormalities in decidualisation in women prior to, and after, pre-eclampsia. Initial growth of the placenta is stimulated by histotroph from the endometrial glands, which contains numerous mitogenic growth factors as well as glucose, lipids and other nutrients. The secretory activity of the glands increases in early pregnancy in response to lactogenic hormones produced by the placenta. However, details of the signalling pathways involved are unknown due to the inaccessibility of the tissues concerned. The recent derivation of endometrial organoids now allows these pathways to be dissected, and prolactin is emerging as a strong stimulant of glandular secretion. Prolactin is secreted by decidual cells, and so may link the transcriptomic data with the supply of extravillous trophoblast cells and deficient arterial remodelling. If the hypothesis were proved correct, the translational impact would be to emphasise the importance of ensuring optimal endometrial function prior to conception. This would have the great advantage of preventing the pre-eclampsia and other placental-related complications at their outset, rather than trying to treat these disorders once established.

CLINICAL AND PATHOGENETIC ASPECTS OF DEVELOPMENT OF GESTATIONAL COMPLICATIONS WITH MULTIPLE PREGNANCY

In order to evaluate the value of the placenta growth factor (PlGF) in the gestational complications during multiple pregnancy, a study of this indicator in serum in 320 pregnant women with multiple pregnancies in the first trimester and in 40 pregnant women with single pregnancy constituted a control group.Goal – The purpose of the study is to investigate the effect of the dynamics of placental growth factors on gestational process during multiple pregnancy.Material and methods of research. A prospective study of maternity pregnancy in 320 females with multiple pregnancy was conducted, which comprised the main group of the subjects and 40 healthy women with singleton pregnancy. The level of PlGF in serum was determined by solid-phase enzyme-linked immunosorbent assay using monoclonal antibody sets in the first trimester of pregnancy. Indicators of the hemostasis system (vascular trombocyte and coagulation link) were evaluated according to generally accepted methods. Dopplerometry of placental and fetal blood flow was performed in uterine arteries (MA), arteries (PA) and umbilical cord veins (PV), middle cerebral artery (CMA) fetuses.Results of the research and their discussion. Women with multiple pregnancy are at risk for developing gestational complications - premature births in 67.9% (p <0.01), fetoplacental dysfunction, preeclampsia - in 17.6% (p <0.05) cases. The revealed violations of the vascular thrombocyte and coagulation homeostasis in the first trimester of pregnancy are the main risk factors for early premature abortion. It has been shown that the low level of placental growth factor in serum of pregnant women with multiple pregnancies in the case of premature labor, fetoplacental dysfunction and preeclampsia (111.23 ± 8.4, 203.24 ± 6.4 and 305.86 ± 7.4 pg / ml) is a prognostic marker in the development of gestating complications, which is reliably confirmed by the conducted research (p <0.01) in comparison with the corresponding indices in single-pregnancy (418.2 ± 10.4 pg / ml).Conclusions. Timely medical correction of gestational complications during multiple pregnancy with the use of micronized progesterone, low molecular weight heparins, angioprotectants allowed prolonging the pregnancy with monochoric type of placentation by 3.2 weeks (up to 34.2 ± 2.4 weeks), and in the case of dichorionique placentation - to term full-term pregnancy

Trans-abdominal in vivo placental vessel occlusion using High Intensity Focused Ultrasound

Pre-clinically, High Intensity Focused Ultrasound (HIFU) has been shown to safely and effectively occlude placental blood vessels in the acute setting, when applied through the uterus. However, further development of the technique to overcome the technical challenges of targeting and occluding blood vessels through intact skin remains essential to translation into human studies. So too does the assessment of fetal wellbeing following this procedure, and demonstration of the persistence of vascular occlusion. At 115 ± 10 d gestational age (term~147 days) 12 pregnant sheep were exposed to HIFU (n = 6), or to a sham (n = 6) therapy through intact abdominal skin (1.66 MHz, 5 s duration, in situ ISPTA 1.3–4.4 kW.cm−2). Treatment success was defined as undetectable colour Doppler signal in the target placental vessel following HIFU exposures. Pregnancies were monitored for 21 days using diagnostic ultrasound from one day before HIFU exposure until term, when post-mortem examination was performed. Placental vessels were examined histologically for evidence of persistent vascular occlusion. HIFU occluded 31/34 (91%) of placental vessels targeted, with persistent vascular occlusion evident on histological examination 20 days after treatment. The mean diameter of occluded vessels was 1.4 mm (range 0.3–3.3 mm). All pregnancies survived until post mortem without evidence of significant maternal or fetal iatrogenic harm, preterm labour, maternal or fetal haemorrhage or infection. Three of six ewes exposed to HIFU experienced abdominal skin burns, which healed without intervention within 21 days. Mean fetal weight, fetal growth velocity and other measures of fetal biometry were not affected by exposure to HIFU. Fetal Doppler studies indicated a transient increase in the umbilical artery pulsatility index (PI) and a decrease in middle cerebral artery PI as a result of general anaesthesia, which was not different between sham and treatment groups. We report the first successful application of fully non-invasive HIFU for occlusion of placental blood flow in a pregnant sheep model, with a low risk of significant complications. This proof of concept study demonstrates the potential of this technique for clinical translation.

Abstract P247: ACE2/ACE Imbalance in the Placental Circulation in an Ovine Model of Intrauterine Growth Restriction

Intrauterine growth restriction (IUGR) has been linked to the development of cardiovascular complications in the offspring. We have previously shown that in an ovine model of IUGR placental blood flow, in both umbilical and uterine artery, was decreased in diet-restricted dams. Angiotensin-converting enzyme (ACE), its metabolite Ang II and the receptor AT1 constitute the vascular-detrimental axis or renin angiotensin system, while ACE2, its metabolite Ang-(1-7) and Mas receptor constitute vasoprotective axis. This study tested the hypothesis that IUGR induces ACE2/ACE imbalance in the placental circulation. In ewe lambs, IUGR was accomplished by providing 60% of the nutrient requirement (RES) while the control group received adequate nutrients (CON) from day 50 to day 130 of gestation. At day 130, plasma samples were collected from umbilical artery (Um-A) and vein (Um-V), uterine artery (Ut-A) and vein (Ut-V), and jugular vein (J-V). ACE and ACE2 enzyme activities were determined by using enzyme-specific fluorogenic substrates, and enzyme-selective inhibitors, captopril and MLN-4760, respectively. Activities were expressed as percent inhibition by the respective inhibitors. ACE2 activity is decreased in the plasma obtained from Um-A (16±2), Um-V (29±4) and Ut-V (31±3) but not in Ut-A of RES group, compared to the CON group (Um-A 25±3, Um-V 42±2 and Ut-V 43±2, P&lt;0.05, P&lt;0.02 and P&lt;.01, respectively, n=5). This resulted in decreased ACE2/ACE (CON: Um-A 0.43±0.03, Um-V 0.84±0.08 and Ut-V 0.82±0.05, and RES: Um-A 0.26±0.02, Um-V 0.46±0.05 and Ut-V 0.5±0.03, P&lt;0.002, P&lt;0.004, P&lt;0.001, respectively). ACE activity was unchanged (n=5) in all four samples of placental circulation. In the J-V plasma ACE2 was decreased (24±2 vs 31±6, NS) and ACE was increased (68±4 vs 54±6, P&lt;0.05) in RES group compared to CON (n=5). This resulted in decreased ACE2/ACE (CON: 0.58±0.04 and RES: 0.3±0.02). These observations suggest that IUGR induces ACE2/ACE imbalance. In the maternal systemic circulation it is largely due to increased ACE, while in the placental circulation it is due to decreased ACE2. Hyperactivity of ACE/Ang II/AT1 receptor pathway due attenuated opposing activity of ACE2 may restrict blood flow to the placental tissues during development.

Predictors of death including quality of positive pressure ventilation during newborn resuscitation and the relationship to outcome at seven days in a rural Tanzanian hospital

BackgroundEffective positive pressure ventilation (PPV) of non-breathing newborns is crucial in facilitating cardio-respiratory adaptation at birth. Identifying predictors of death in newborns receiving PPV is important in order to facilitate preventative strategies.ObjectiveThe objective of this study was to determine the perinatal predictors of death including the quality of PPV administered among admitted newborns.MethodsAn observational study of admitted newborns who received PPV after birth was conducted. Research assistants observed all deliveries and recorded perinatal events on data collection forms. Measured heart rate (HR) and ventilation parameters were then compared between newborns who died and survivors.ResultsNewborns (n = 232) were studied between October 2014 and November 2016. Newborns who died (n = 53) compared to survivors (n = 179) had more fetal heart rate (FHRT) abnormalities (12/53 vs 19/179; p = 0.03); lower initial HR (<100 beats/minute) at start of PPV (44/48 vs 77/139; p<0.001); and a longer time for HR to increase >100 beats/minute from birth (180 vs 149 seconds; p = 0.07). Newborns who died compared to survivors took longer time (14 vs 4 seconds; p = 0.008) and more inflations (7 vs 3; p = 0.006) to achieve an expired volume (Vt) of 6 ml/kg, respectively. Median delivered Vt during the first 60 seconds of PPV was less in newborns who died compared to survivors (5 vs 6 ml/kg; p = 0.12). Newborns who died proceeded to severe encephalopathy (15/31 vs 1/59; p<0.001) compared to survivors.ConclusionDepressed newborns who proceeded to death compared to survivors, exhibited delayed HR response to PPV which may partly reflect FHRT abnormalities related to interruption of placental blood flow, and/or a timely delay in establishing adequate Vt. Depressed newborns progressed to moderate/severe encephalopathy. Improving FHRT monitoring to identify fetuses at risk for expedited delivery, coupled with optimizing delivery room PPV might decrease mortality in this setting.

The value of middle cerebral artery to umbilical artery ratio by Doppler velocimetry in low risk postdate pregnancies

Background and objective: Placental insufficiency is the primary cause of intrauterine growth restriction in normally formed fetuses and can be identified using middle cerebral artery to umbilical artery ratio Doppler velocimetry, and provide an estimate of downstream placental vascular resistance and placental blood flow. There is a strong association between reduced end-diastolic umbilical artery blood flow velocity and increased vascular resistance in umbilical placental microcirculation. Doppler ultrasound can assess the uteroplacental blood flow just before labor. This study aimed to investigate the use of the fetal cerebroumbilical ratio to predict the intrapartum fetal compromise in appropriately grown fetuses. Methods: A comparative cross-sectional study set at Sulaimania Maternity Teaching Hospital, Sulaimania, Iraq, from January to June 2015. The study recruited 121 cases, fetal biometry and Doppler indices were measured before established labor. The intrapartum and neonatal outcome details recorded. Results: Infants delivered by cesarean section for fetal compromise had significantly lower cerebroumbilical ratio than those born by spontaneous normal (none assisted) vaginal delivery and by cesarean section for other intrapartum causes. Infants with cerebroumbilical ratio 10th percentile. A cerebroumbilical ratio >90th percentile appears protective against cesarean section for fetal compromise. Amniotic fluid index of < 5 was associated with an increased cesarean section for fetal indication. Conclusion The cerebroumbilical ratio can identify fetuses at high risk of intrapartum fetal compromise. As a confounding variable, the amniotic fluid index was a useful tool for surveillance in prolonged pregnancy.

Maternal high-fat diet reversal improves placental hemodynamics in a nonhuman primate model of diet-induced obesity.

BackgroundIn a Japanese macaque model of diet-induced obesity, we have previously demonstrated that consumption of a high fat, ‘Western-style’ diet (WSD) is associated with placental dysfunction and adverse pregnancy outcomes, independent of an obese maternal phenotype. Specifically, we have reported decreased uterine placental blood flow and increased inflammation with maternal WSD consumption. We also previously investigated the use of a promising therapeutic intervention that mitigated the adverse placental effects of a WSD but had unexpected detrimental effects on fetal pancreatic development. Thus, the objective of the current study was to determine whether simple preconception diet reversal would improve placental function.MethodsFemale Japanese macaques were divided in to three groups: diet reversal animals (n=5) were switched from a chronic WSD (36% fat) to a low fat, control diet (14% fat) prior to conception and throughout pregnancy. The control (n=6) and WSD (n=6) cohorts were maintained on their respective diets throughout pregnancy. Maternal body weight and composition were regularly assessed and advanced non-invasive imaging was performed at mid-gestation (gestational day 90, G90 or 0.5 of gestation, where full term is G175), and G129, one day prior to C-section delivery at G130 (0.75 of gestation). Imaging studies comprised Doppler ultrasound (US), Contrast-Enhanced US (CEUS) and Dynamic-Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) to assess uteroplacental hemodynamics and maternal-side placental perfusion.ResultsDietary intervention resulted in significant maternal weight loss prior to pregnancy, and improved lean to fat mass ratio. By advanced imaging we demonstrated that a chronic WSD led to decreased blood flow velocity in the intervillous space, delayed blood flow transfer through the maternal spiral arteries and reduced total placental blood flow compared to control fed animals. Dietary reversal ameliorated these concerning derangements, restoring these hemodynamic parameters to control levels.ConclusionPreconception dietary modification has beneficial effects on the maternal metabolic phenotype, and results in improved placental hemodynamics.

Acute tocolysis for uterine tachysystole or suspected fetal distress

Acute tocolysis for uterine tachysystole or suspected fetal distress

An effect of maternal nifedipine therapy on fetoplacental blood flow: a prospective study.

The aim of this study is to assess the effects of maternal nifedipine administration on placental and fetal blood flow. A total of 29 patients with preterm labor diagnosis admitted to the tertiary care center, Zeynep Kamil Hospital, were evaluated. Before and 24-48h after administration of oral nifedipine, Doppler ultrasound scan was carried out to measure fetal middle cerebral artery, ductus venosus, umbilical artery, and maternal uterine artery blood flow. After 24 and 48h of therapy, there were no changes in mean PI and RI in the umbilical arteries and ductus venosus (p > 0.05). Fetal middle cerebral artery and maternal uterine artery PI and RI values showed a significant reduction 24-48h after oral nifedipine therapy (p < 0.05). Our study showed that 24 and 48h after oral nifedipine therapy, there is a significant increase in fetal MCA and maternal uterine artery blood flow, while fetal umbilical artery and ductus venosus Doppler values do not change.

Alcohol and fetoplacental vasoconstrictor reactivity.

Alcohol abuse during pregnancy is a well-known factor in fetal morbidity, including smaller fetal size. We have shown that chronic hypoxia, considered the main pathogenetic factor in intrauterine growth restriction, elevates fetoplacental vascular resistance (and vasoconstrictor reactivity) and thus, presumably, reduces placental blood flow. We thus hypothesized that alcohol may affect the fetus - in addition to other mechanisms - by altering fetoplacental vascular resistance and/or reactivity. Using isolated, double-perfused rat placenta model, we found that maternal alcohol intake in the last third of gestation doubled the vasoconstrictor responses to angiotensin II but did not affect resting vascular resistance. Reactivity to acute hypoxic challenges was unchanged. Chronic maternal alcohol intake in a rat model alters fetoplacental vasculature reactivity; nevertheless, these changes do not appear as serious as other detrimental effects of alcohol on the fetus.