Utero-placental vascularisation in normal and preeclamptic and intra-uterine growth restriction pregnancies: third trimester quantification using 3D power Doppler with comparison to placental vascular morphology (EVUPA): a prospective controlled study

Role of Placental Vascularization Indices and Shear Wave Elastography in Fetal Growth Restriction

Objective

To evaluate the role of placental vascularisation indices using 3D-Power Doppler and placental elasticity using Shear Wave Elastography (SWE) in Fetal Growth Restricted (FGR) pregnancies and to assess their correlation with perinatal outcomes.

Methods

This prospective case-control study was conducted from June 2018-2020. Thirty women with FGR and thirty controls (24-36 weeks) underwent grayscale and Doppler ultrasonography followed by measurement of vascularisation indices and SWE from the central and peripheral parts of fetal and maternal surfaces of the placenta. Participants were followed till delivery and perinatal outcomes were noted.

Results

Vascularisation indices were significantly reduced among FGR vs. controls: Vascularisation Index (VI): 20.90 ± 5.46 vs. 31.49 ± 3.89, Flow Index (FI): 26.29 ± 1.70 vs. 30.85 ± 2.02, Vascularisation- Flow Index (VFI): 7.06 ± 2.42 vs. 12.37 ± 2.43, p < 0.001. The mean placental SWE (17.36 ± 1.50 kPa) in FGR pregnancies was significantly higher as compared to controls (4.14 ± 1.14 kPa), p < 0.001. Neonatal polycythaemia and hyperbilirubinemia were significantly increased in FGR pregnancies with higher SWE value. Receiver operating characteristic curve-based cut-off of VI for intensive care requirement was 23.0 (sensitivity: 75%, specificity: 71%) and for tachypnea was 22.8 (73% sensitivity and specificity). The cut-off of FI for low birth weight was 25.7 (sensitivity: 69.6%, specificity: 71.4%).

Conclusion

This study demonstrates that increased placental stiffness and reduced vascularisation in FGR indicate possible placental pathology. Both modalities help in predicting perinatal complications. Hence, vascularisation indices and SWE reflect the extent of placental insufficiency and can be useful adjuncts in diagnosis.

Altered placental ion channel gene expression in preeclamptic high-altitude pregnancies

High-altitude (>2,500 m) residence increases the risk of pregnancy vascular disorders such as fetal growth restriction and preeclampsia, each characterized by impaired placental function. Genetic attributes of highland ancestry confer relative protection against vascular disorders of pregnancy at high altitudes. Although ion channels have been implicated in placental function regulation, neither their expression in high-altitude placentas nor their relationship to high-altitude preeclampsia has been determined. Here, we measured the expression of 26 ion-channel genes in placentas from preeclampsia cases and normotensive controls in La Paz, Bolivia (3,850 m). In addition, we correlated gene transcription to maternal and infant ancestry proportions. Gene expression was assessed by PCR, genetic ancestry evaluated by ADMIXTURE, and ion channel proteins localized by immunofluorescence. In preeclamptic placentas, 11 genes were downregulated (ABCC9, ATP2A2, CACNA1C, KCNE1, KCNJ8, KCNK3, KCNMA1, KCNQ1, KCNQ4, PKD2, and TRPV6) and two were upregulated (KCNQ3 and SCNN1G). KCNE1 expression was positively correlated with high-altitude Amerindian ancestry and negatively correlated with non-high altitude. SCNN1G was negatively correlated with African ancestry, despite minimal African admixture. Most ion channels were localized in syncytiotrophoblasts (Cav1.2, TRPP2, TRPV6, and Kv7.1), whereas expression of Kv7.4 was primarily in microvillous membranes, Kir6.1 in chorionic plate and fetal vessels, and MinK in stromal cells. Our findings suggest a role for differential placental ion channel expression in the development of preeclampsia. Functional studies are needed to determine processes affected by these ion channels in the placenta and whether therapies directed at modulating their activity could influence the onset or severity of preeclampsia.

Relationship between placental hemodynamics and placental histological analysis in third trimester

AIM

To investigate whether vascularization index (VI), flow index (FI), and vascularization flow index (VFI) correlate with the pathological structure of the placenta and whether there were any differences in VI, FI, VFI, and placental pathological structure between the normal and preeclampsia (PE) groups.

METHODS

Fifty-five pregnant women (normal group, n = 27; PE group, n = 28) underwent VI, FI, and VFI at four locations in the placenta during the second and third trimesters. Two hematoxylin and eosin (HE)-stained specimens of the postpartum placenta were prepared. We randomly selected two of these locations and used ImageJ, an open-source image package, to quantify intervillous blood vessels (IBV), intervillous spaces (IS), and intervillous blood vessels + intervillous spaces (IBV + IS) per unit placenta and analyzed their correlation with VI, FI, and VFI.

RESULTS

There was no positive correlation between VI, FI, VFI, IBV, IS, and IBV + IS. There were no significant differences in VI, FI, and VFI between the normal and PE groups; however, there were significant differences in IBV, IS, and IBV + IS in the PE group compared to those in the normal group.

CONCLUSIONS

Placental hemodynamics measured by VI, FI, and VFI were not positively correlated with placental morphology in the third trimester. There were no differences in the VI, FI, and VFI in the third trimester between the normal and PE groups, suggesting that these may reflect placental circulatory insufficiency.

New insights into human functional ultrasound imaging

Ultrasound imaging is a vital tool for exploring in vivo the placental function which is essential to understand pathological phenomena such as preeclampsia or intrauterine growth restriction. As technology advances including ready availability of three-dimensional (3D) probes and novel software, new markers of placental function become possible. The objective of this review was to provide an overview of the new ultrasound markers of placental function with a focus on the potential clinical application of three-dimensional power Doppler (3DPD). A broad-free text literature search was undertaken based on human placental studies and sixty full-text studies were included in this review. Three-dimensional power Doppler is a promising technique to predict preeclampsia in the first trimester. However, the influence of external factors such as body mass index, parameter standardisation and machine settings still need to be addressed. Contrast-enhanced ultrasound is currently reserved for research, because the required injected contrast mediums are not currently approved for use in pregnancy, although the safety data is reassuring.

Analysis of ultrasonographic and hystopathologic features of placental invasiveness in Vitro Fertilization (IVF) pregnancies: a prospective study

PURPOSE

In Vitro Fertilization (IVF) techniques make up 1.5-5% of all births in developed countries. These pregnancies are characterized by implantation and functional alterations of the placenta, higher incidence of multiple pregnancies, higher incidence of hypertensive syndromes and pre and post partum hemorrhage (PPH).

METHODS

Since January 2017 to May 2018 all single IVF pregnancies coming to San Camillo Hospital were considered prospectively for routine pregnancy checks until delivery and compared with a control group of spontaneous pregnancies. Each patient underwent to an obstetrical ultrasound of the third trimester at our clinic, with particular attention on the study of the placenta. Birth modalities, type and timing of third stage of labor, peri and post-partum complications were recorded.

RESULTS

We had a higher incidence of cesarean sections in the IVF group (85% versus 25%) and peri and post-partum complications (38% versus 5%). We recorded a statistically significant difference of reduction in IVF pregnancies of VI (p = .0039) and VFI (p = .0043), while the FI index was not statistically significant in the two study groups (p = .4351).

CONCLUSION

Despite the small sample size of our study, our data follow the trend of scientific literature, with an effective increase in placental anomalies in IVF pregnancies compared to healthy controls.

Role of first-trimester three-dimensional (3D) power Doppler of placental blood flow and 3D placental volume in early prediction of pre-eclampsia

OBJECTIVE

To assess the efficacy of first-trimester three-dimensional (3D) placental volume as well as 3D power Doppler of placental vascular indices for early prediction of pre-eclampsia.

METHODS

The prospective cohort study included over 2019 women with a singleton pregnancy in their first trimester at 11-13+ weeks of pregnancy. All women were examined by 3D abdominal ultrasound, including Doppler techniques for the placental volume and placental vascular indices. Uterine artery Doppler indices were also assessed. All participants were cared for until delivery for assessment of pregnancy outcomes.

RESULTS

In all, 163 women developed pre-eclampsia while 1856 women remained normotensive. The women with pre-eclampsia had significantly lower placental volume (77.09 ml vs. 99.8 ml, p < 0.001), and placental vascular indices (vascularization index, flow index, and vascularization flow index were 7.41 vs. 9.89, 39.03 vs. 46.63, and 2.77 vs. 4.4, respectively, p < 0.001). In contrast, women with pre-eclampsia had significantly high mean uterine pulsatility index and resistance index (2.02 vs. 1.11, 0.83 vs. 0.64, respectively, p < 0.001) compared with the normotensive women. The placental vascular indices were highly sensitive, whereas the placental volume and the mean uterine pulsatility index and resistance index had higher specificity for the prediction of pre-eclampsia.

CONCLUSION

First-trimester assessment through 3D placental volume and power Doppler of placental vascular indices, especially in combination with uterine artery Doppler assessment, revealed an increase in the accuracy of early detection of women at risk for developing pre-eclampsia.

Oral L-glutamine rescues fructose-induced poor fetal outcome by preventing placental triglyceride and uric acid accumulation in Wistar rats

BACKGROUND

Metabolic adaptation of pregnant mothers is crucial for placental development and fetal growth/survival. However, evidence exists that indiscriminate consumption of fructose-enriched drink (FED) during pregnancy disrupts maternal-fetal metabolic tolerance with attendant adverse fetal outcomes. Glutamine supplementation (GLN) has been shown to exert a modulatory effect in metabolic disorders. Nevertheless, the effects of GLN on FED-induced poor fetal outcome, and in particular the impacts on placental uric acid/lipid accumulation are unknown. The present study was conducted to test the hypothesis that oral GLN improves fetal outcome by attenuating placental lipid accumulation and uric acid synthesis in pregnant rats exposed to FED.

MATERIALS AND METHODS

Pregnant Wistar rats (160-180 g) were randomly allotted to control, GLN, FED and FED + GLN groups (6 rats/group). The groups received vehicle by oral gavage, glutamine (1 g/kg) by oral gavage, fructose (10%; w/v) and fructose + glutamine, respectively, through gestation.

RESULTS

Data showed that FED during pregnancy caused placental inefficiency, reduced fetal growth, and caused insulin resistance with correspondent increase in fasting blood glucose and plasma insulin. FED also resulted in an increased placental triglyceride, total cholesterol and de novo uric acid synthesis by activating adenosine deaminase and xanthine oxidase activities. Moreover, FED during pregnancy led to increased lipid peroxidation, lactate production with correspondent decreased adenosine and glucose-6-phosphate dehydrogenase-dependent antioxidant defense. These alterations were abrogated by GLN supplementation.

CONCLUSION

These findings implicate that high FED intake during pregnancy causes poor fetal outcome via defective placental uric acid/triglyceride-dependent mechanism. The findings also suggest that oral GLN improves fetal outcome by ameliorating placental defects through suppression of uric acid/triglyceride accumulation.

Spiral artery blood flow during pregnancy: a systematic review and meta-analysis

Background

Downstream remodeling of the spiral arteries (SpA) decreases utero-placental resistance drastically, allowing sustained and increased blood flow to the placenta under all circumstances. We systematically evaluated available reports to visualize adaptation of spiral arteries throughout pregnancy by ultra-sonographic measurements and evaluated when this process is completed.

Methods

A systematic review and meta-analysis of spiral artery flow (pulsatility index (PI), resistance index (RI) and peak systolic velocity (PSV)) was performed. English written articles were obtained from Pubmed, EMBASE and Cochrane Library and included articles were assessed on quality and risk of bias. Weighted means of Doppler indices were calculated using a random-effects model.

Results

In healthy pregnancies, PI and RI decreased from 0.80 (95% CI: 0.70–0.89) and 0.50 (95% CI: 0.47–0.54) in the first trimester to 0.50 (95% CI: 0.45–0.55, p < 0.001) and 0.39 (95% CI: 0.37–0.42, p < 0.001) in the second trimester and to 0.49 (95% CI: 0.44–0.53, p = 0.752) and 0.36 (95% CI: 0.35–0.38, p = 0.037) in the third trimester, respectively. In parallel, PSV altered from 0.22 m/s (95% CI: 0.13–0.30 m/s) to 0.28 m/s (95% CI: 0.17–0.40 m/s, p = 0.377) and to 0.25 m/s (95% CI: 0.20–0.30 m/s, p = 0.560) in the three trimesters. In absence of second and third trimester Doppler data in complicated gestation, only a difference in PI was observed between complicated and healthy pregnancies during the first trimester (1.49 vs 0.80, p < 0.001). Although individual studies have identified differences in PI between SpA located in the central part of the placental bed versus those located at its periphery, this meta-analysis could not confirm this (p = 0.349).

Conclusions

This review and meta-analysis concludes that an observed decrease of SpA PI and RI from the first towards the second trimester parallels the physiological trophoblast invasion converting SpA during early gestation, a process completed in the midst of the second trimester. Higher PI was found in SpA of complicated pregnancies compared to healthy pregnancies, possibly reflecting suboptimal utero-placental circulation. Longitudinal studies examining comprehensively the predictive value of spiral artery Doppler for complicated pregnancies are yet to be carried out.

Uterine transplantation and IVF for congenital or acquired uterine factor infertility: A systematic review of safety and efficacy outcomes in the first 52 recipients

Uterine transplantation (UTx) associated with IVF restores fertility in women affected by absolute uterine factor infertility (AUFI). Pregnancies achieved both in women undergoing any solid organ transplantation and following IVF are associated with an increased risk of maternal and neonatal complications. This systematic review evaluated this risk in UTx-IVF treated women focusing on the safety and efficacy features of the treatment. Twenty-two studies and three press releases reporting on 52 UTx-IVF treatments were identified. Regarding the safety of treatment, 38/52 (73,1%) of surgical procedures led to the restoration of uterine function in recipients, 12/52 (23,1%) of recipients experienced post-operative complications requiring hysterectomy, and 2/52 (3,8%) of procedures failed before uterine recipients’ surgery due to intra-operative complications. Regarding the efficacy of treatment, results focused on transplanted patients showing full recovery of organ functioning: 16/38 (42,1%) of patients achieved a pregnancy, including two women who gave births twice. UTx-IVF pregnancies led to 16 deliveries and all new-borns were healthy. Six out of 16 (37,5%) UTx pregnancies faced major complications during gestation. Preterm births occurred in 10/16 (62,5%) UTx deliveries. Our data indicates that the risk of gestational and delivery complications deserves important consideration in AUFI women receiving UTx-IVF treatments. However, these observations are preliminary and need to be revised after larger series of data are published.

Assessment of uteroplacental vascularisation in early first-trimester pregnancy with contrast-enhanced ultrasound and 3D power Doppler angiography: protocol for a prospective, cross-sectional, multicentre and non-randomised open study ("HOPE Study")

INTRODUCTION

Knowledge about the mechanisms leading to the establishment of uteroplacental vascularisation is inadequate, and some of what has been thought to be known for decades has recently been challenged by showing that the intervillous space, the major area of maternal-fetal exchange, appears to be perfused by maternal blood at as early as 6 weeks of gestation. The vascular flow then seems relatively constant until 13 weeks when it appears to increase suddenly.

OBJECTIVES

The principal objective is to quantify the perfusion of the intervillous space by contrast-enhanced ultrasonography (CEUS) during the first-trimester at three different gestational ages (8, 11 and 13 weeks). The secondary objectives are to: (1) describe the indicators of vascularisation of the placenta (intervillous space) and the myometrium at the three gestational ages, measured by CEUS and three-dimensional power Doppler (3DPD) angiography; (2) compare the diagnostic performance of CEUS and 3DPD for the demonstration and quantification of uteroplacental vascularisation and (3) establish a biological collection of placentas to increase knowledge about placental development and functions during pregnancy.

METHODS AND ANALYSIS

This is a prospective, cross-sectional, multicentre and non-randomised open study. We will include 42 women with ongoing pregnancy and divided into three groups of gestational ages (ie, 14 women by per group): 8, 11 and 13 weeks of gestation. 3DPD and then CEUS will be performed and the data about the perfusion kinetics and the 3DPD indices will be calculated and then compared with each other and for each gestational age.

ETHICS AND DISSEMINATION

The appropriate French Ethics Committee Est III approved this study and the related consent forms on 5 April 2016, and the competent authority (Agence Nationale de Sécurité du Médicament et des Produits de Santé) authorised the study on 21 June 2016. The results of this study will be published in a peer-reviewed journal and will be presented at relevant conferences.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov registry (NCT02884297); EudraCT registry (2015-005655-27).

Three-dimensional Doppler ultrasonography for the assessment of fetal liver vascularization in fetuses with intrauterine growth restriction

OBJECTIVE

To demonstrate changes in hepatic volume and vascular indices in fetuses with intrauterine growth restriction (IUGR) compared with normal-growth fetuses, using a noninvasive method (three-dimensional power Doppler ultrasound).

METHODS

The present cross-sectional study was conducted between September 1 and November 30, 2014, at a maternal-fetal medicine unit in Bogotá, Colombia; it included consecutive women at 24-34 weeks of pregnancy. The fetal liver volume and indices of hepatic vascularization were determined with three-dimensional power Doppler ultrasonography and compared between fetuses with and without a diagnosis of IUGR. Results A total of 119 women met study inclusion criteria; 97 fetuses had no growth restriction, whereas 22 fetuses had IUGR. The latter group had decreased liver volume (57.85 ± 29.71 mL vs 86.99 ± 31.24 mL; P=0.010) and increased vascular indices (vascularization index, 47.92 ± 34.44 versus 22.46 ± 18.95; flow index, 71.39 ± 42.01 versus 41.11 ± 23.24; vascularization flow index, 47.94 ± 47.96 versus 13.67 ± 22.38; P=0.003 for all comparisons).

CONCLUSION

Liver volume was decreased and liver vascular indices values were increased in fetuses with IUGR. These findings imply that evaluation of hepatic vascularization with three-dimensional hepatic Doppler could be useful in the diagnosis of IUGR.

Maternal one carbon metabolism through increased oxidative stress and disturbed angiogenesis can influence placental apoptosis in preeclampsia

Adequate maternal nutrition is critical for a healthy pregnancy outcome and poor maternal nutrition is known to be associated with pregnancy complications like preeclampsia. We have earlier demonstrated that there is an imbalance in the levels of micronutrients (folate and vitamin B₁₂) along with low levels of long chain polyunsaturated fatty acids (LCPUFA) and high homocysteine levels in women with preeclampsia. Homocysteine is known to be involved in the formation of free radicals leading to increased oxidative stress. Higher oxidative stress has been shown to be associated with increased apoptotic markers in the placenta. Preeclampsia is of placental origin and is associated with increased oxidative stress, disturbed angiogenesis and placental apoptosis. The process of angiogenesis is important for placental and fetal development and various angiogenic growth factors inhibit apoptosis by inactivation of proapoptotic proteins through a series of cellular signalling pathways. We propose that an altered one carbon cycle resulting in increased oxidative stress and impaired angiogenesis will contribute to increased placental apoptosis leading to preeclampsia. Understanding the association of one carbon cycle components and the possible mechanisms through which they regulate apoptosis will provide clues for reducing risk of pregnancy complications.

First trimester placental vascularization and angiogenetic factors are associated with adverse pregnancy outcome

BACKGROUND

Hypertensive disorders, fetal growth restriction and preterm birth are major obstetrical complications and are related to impaired placentation. Early identification of impaired placentation can advance clinical care by preventing or postpone adverse pregnancy outcome.

OBJECTIVES

Determine whether sonographic assessed placental vascular development and concomitant changes in inflammation- and/or angiogenesis-related serumproteins differ in the first trimester between uncomplicated pregnancies and pregnancies with adverse outcome.

STUDY DESIGN

This prospective longitudinal study defines adverse pregnancy outcome as conditions associated with impaired placentation; fetal growth restriction, hypertensive disorder, preterm birth and placental abruption. The vascularization index, flow index, vascularization flow index and placental volume were determined at 8, 10 and 12 weeks pregnancy from 64 women using 3D power Doppler. Serum levels were analyzed for Angiopoetin-1 and -2, Leptin, VEGF-R, VEGF, and EGF.

RESULTS

The vascularization index and vascular flow index increased in uneventful pregnancies with almost 50% between 8 and 12 weeks, resulting in a ∼50% higher vascularization index at 12 weeks compared to women with an adverse pregnancy outcome. Women with an adverse pregnancy outcome (n = 13) had significantly lower indices and placental volumes at all time points measured and these indices did not increase between 8 and 12 weeks. Reduced vascular development was associated with increased Angiopoietin-1 levels at 8 and 12 weeks and increased Leptin levels at 8 weeks.

CONCLUSIONS

Pregnancies with an adverse outcome caused by conditions associated with impaired placentation differ from uneventful pregnancies in having reduced placental vascularization accompanied by elevated circulating levels of Angiopoietin-1 and Leptin already in the first trimester.

Use of prokineticin-1 (PROK1), pregnancy-associated plasma protein A (PAPP-A) and PROK1/PAPP-A ratio to predict adverse pregnancy outcomes in the first trimester: a prospective study

INTRODUCTION

To compare the predictive effectiveness levels of prokineticin-1 (PROK1), pregnancy-associated plasma protein A (PAPP-A) and the PROK1/PAPP-A ratio in the first trimester for preeclampsia (PE), foetal growth restriction (FGR), gestational diabetes mellitus (GDM) and spontaneous preterm birth (SPB).

MATERIALS AND METHODS

A total of randomly selected 162 pregnant women were included. Peripheral blood samples were obtained between 11^0/7 and 13^6/7 gestational weeks (GWs). All women were followed throughout the pregnancy and classified into five groups as having PE, FGR, GDM, SPB and uncomplicated pregnancies. The cut-off levels of the markers were identified to predict adverse outcomes.

RESULTS

PROK1 predicted PE with 83.3% sensitivity, 85.7% specificity at a value of >293.4 pg/mL; at a value of >260.2 pg/mL, PROK1 predicted FGR with 85.7% sensitivity, 72.5% specificity in the first trimester. The area under receiver operating characteristic (ROC) curve of PAPP-A was lower than that of PROK1 and PROK1/PAPP-A in differentiating PE and FGR from the uncomplicated group (p < .001). PROK1 levels and the PROK1/PAPP-A ratios in the SPB and GDM groups were lower than in the uncomplicated group (p < .01).

CONCLUSIONS

Elevated PROK1 in the first trimester is a more effective marker than PAPP-A in the prediction of PE and FGR. Lower PROK1 levels are associated with the development of SPB and GDM.

Non-invasive evaluation of placental blood flow: lessons from animal models

In human obstetrics, placental vascularisation impairment is frequent as well as linked to severe pathological events (preeclampsia and intrauterine growth restriction), and there is a need for reliable methods allowing non-invasive evaluation of placental blood flow. Uteroplacental vascularisation is complex, and animal models are essential for the technical development and safety assessment of these imaging tools for human clinical use; however, these techniques can also be applied in the veterinary context. This paper reviews how ultrasound-based imaging methods such as 2D and 3D Doppler can provide valuable insight for the exploration of placental blood flow both in humans and animals and how new approaches such as the use of ultrasound contrast agents or ultrafast Doppler may allow to discriminate between maternal (non-pulsatile) and foetal (pulsatile) blood flow in the placenta. Finally, functional magnetic resonance imaging could also be used to evaluate placental blood flow, as indicated by studies in animal models, but its safety in human pregnancy still requires to be confirmed.