Placental histological patterns and uterine artery Doppler velocimetry in pregnancies complicated by early or late pre-eclampsia

Implementation of First-Trimester Screening and Prevention of Preeclampsia: A Stepped Wedge Cluster-Randomized Trial in Asia

BACKGROUND

This trial aimed to assess the efficacy, acceptability, and safety of a first-trimester screen-and-prevent strategy for preterm preeclampsia in Asia.

METHODS

Between August 1, 2019, and February 28, 2022, this multicenter stepped wedge cluster randomized trial included maternity/diagnostic units from 10 regions in Asia. The trial started with a period where all recruiting centers provided routine antenatal care without study-related intervention. At regular 6-week intervals, one cluster was randomized to transit from nonintervention phase to intervention phase. In the intervention phase, women underwent first-trimester screening for preterm preeclampsia using a Bayes theorem-based triple-test. High-risk women, with adjusted risk for preterm preeclampsia ≥1 in 100, received low-dose aspirin from <16 weeks until 36 weeks.

RESULTS

Overall, 88.04% (42 897 of 48 725) of women agreed to undergo first-trimester screening for preterm preeclampsia. Among those identified as high-risk in the intervention phase, 82.39% (2919 of 3543) received aspirin prophylaxis. There was no significant difference in the incidence of preterm preeclampsia between the intervention and non-intervention phases (adjusted odds ratio [aOR], 1.59 [95% CI, 0.91-2.77]). However, among high-risk women in the intervention phase, aspirin prophylaxis was significantly associated with a 41% reduction in the incidence of preterm preeclampsia (aOR, 0.59 [95% CI, 0.37-0.92]). In addition, it correlated with 54%, 55%, and 64% reduction in the incidence of preeclampsia with delivery at <34 weeks (aOR, 0.46 [95% CI, 0.23-0.93]), spontaneous preterm birth <34 weeks (aOR, 0.45 [95% CI, 0.22-0.92]), and perinatal death (aOR, 0.34 [95% CI, 0.12-0.91]), respectively. There was no significant between-group difference in the incidence of aspirin-related severe adverse events.

CONCLUSIONS

The implementation of the screen-and-prevent strategy for preterm preeclampsia is not associated with a significant reduction in the incidence of preterm preeclampsia. However, low-dose aspirin effectively reduces the incidence of preterm preeclampsia by 41% among high-risk women. The screen-and-prevent strategy for preterm preeclampsia is highly accepted by a diverse group of women from various ethnic backgrounds beyond the original population where the strategy was developed. These findings underpin the importance of the widespread implementation of the screen-and-prevent strategy for preterm preeclampsia on a global scale.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03941886.

Preeclampsia and timing of delivery: Disease severity, maternal and perinatal outcomes

OBJECTIVES

This study aimed to elucidate clinical characteristics, disease severity, and obstetric outcomes in women with pregnancy complicated with preeclampsia stratified by gestational age at delivery.

STUDY DESIGN

This retrospective study was conducted at a tertiary care facility from January 2011 to December 2020.

MAIN OUTCOME MEASURES

Maternal characteristics, risk factors, clinical signs and symptoms, laboratory test results, and maternal and perinatal outcomes were compared between early (<34 weeks) versus late (≥34 weeks) and preterm (<37 weeks) versus term (≥37 weeks) preeclampsia.

RESULTS

More than half of the women (56 %, 612/1094) had preterm preeclampsia. Overall, 30 % (329/1094) delivered before 34 weeks of gestation. Pregnancies with early preeclampsia had the worst maternal signs and symptoms, the highest median blood pressure level, and more abnormal laboratory abnormalities compared to those with late preeclampsia. Additionally, women with co-morbid diseases (chronic hypertension, chronic kidney disease, and systemic lupus erythematosus) were more likely to develop early than late preeclampsia. Of note, although adverse maternal and perinatal events occurred more commonly in early rather than late preeclampsia, 18 % (7/39) of eclampsia and 16 % (8/50) of hemolysis, elevated liver enzymes, and low platelet count syndrome cases occurred after 37 weeks of gestation.

CONCLUSIONS

Early preeclampsia posed the highest risk to the mother and infant(s); however, adverse maternal and perinatal events were still present even in cases of preeclampsia at term. Therefore, it is crucial for healthcare practitioners to remain vigilant and manage all cases with great care to prevent adverse outcomes.

Integrated unbiased multiomics defines disease-independent placental clusters in common obstetrical syndromes

BACKGROUND

Placental dysfunction, a root cause of common syndromes affecting human pregnancy, such as preeclampsia (PE), fetal growth restriction (FGR), and spontaneous preterm delivery (sPTD), remains poorly defined. These common, yet clinically disparate obstetrical syndromes share similar placental histopathologic patterns, while individuals within each syndrome present distinct molecular changes, challenging our understanding and hindering our ability to prevent and treat these syndromes.

METHODS

Using our extensive biobank, we identified women with severe PE (n = 75), FGR (n = 40), FGR with a hypertensive disorder (FGR + HDP; n = 33), sPTD (n = 72), and two uncomplicated control groups, term (n = 113), and preterm without PE, FGR, or sPTD (n = 16). We used placental biopsies for transcriptomics, proteomics, metabolomics data, and histological evaluation. After conventional pairwise comparison, we deployed an unbiased, AI-based similarity network fusion (SNF) to integrate the datatypes and identify omics-defined placental clusters. We used Bayesian model selection to compare the association between the histopathological features and disease conditions vs SNF clusters.

RESULTS

Pairwise, disease-based comparisons exhibited relatively few differences, likely reflecting the heterogeneity of the clinical syndromes. Therefore, we deployed the unbiased, omics-based SNF method. Our analysis resulted in four distinct clusters, which were mostly dominated by a specific syndrome. Notably, the cluster dominated by early-onset PE exhibited strong placental dysfunction patterns, with weaker injury patterns in the cluster dominated by sPTD. The SNF-defined clusters exhibited better correlation with the histopathology than the predefined disease groups.

CONCLUSIONS

Our results demonstrate that integrated omics-based SNF distinctively reclassifies placental dysfunction patterns underlying the common obstetrical syndromes, improves our understanding of the pathological processes, and could promote a search for more personalized interventions.

Definition and Quantification of Three-Dimensional Imaging Targets to Phenotype Pre-Eclampsia Subtypes: An Exploratory Study

Pre-eclampsia is a severe placenta-related complication of pregnancy with limited early diagnostic and therapeutic options. Aetiological knowledge is controversial, and there is no universal consensus on what constitutes the early and late phenotypes of pre-eclampsia. Phenotyping of native placental three-dimensional (3D) morphology offers a novel approach to improve our understanding of the structural placental abnormalities in pre-eclampsia. Healthy and pre-eclamptic placental tissues were imaged with multiphoton microscopy (MPM). Imaging based on inherent signal (collagen, and cytoplasm) and fluorescent staining (nuclei, and blood vessels) enabled the visualization of placental villous tissue with subcellular resolution. Images were analysed with a combination of open source (FIJI, VMTK, Stardist, MATLAB, DBSCAN), and commercially (MATLAB) available software. Trophoblast organization, 3D-villous tree structure, syncytial knots, fibrosis, and 3D-vascular networks were identified as quantifiable imaging targets. Preliminary data indicate increased syncytial knot density with characteristic elongated shape, higher occurrence of paddle-like villous sprouts, abnormal villous volume-to-surface ratio, and decreased vascular density in pre-eclampsia compared to control placentas. The preliminary data presented indicate the potential of quantifying 3D microscopic images for identifying different morphological features and phenotyping pre-eclampsia in placental villous tissue.

Hypertensive Disorders of Pregnancy and Fetal Growth Restriction: Clinical Characteristics and Placental Lesions and Possible Preventive Nutritional Targets

Background: The purpose of this study was to describe the placental lesions in pregnancies complicated by hypertensive disorders (HDP) and/or fetal growth restriction (FGR) and in uneventful control pregnancies. Methods: This is a case control study that included singleton pregnancies with HDP and normally grown fetus (HDP-AGA fetus), with HDP and FGR, early FGR, late FGR, and uneventful pregnancies. Feto-placental Doppler velocimetry and sFlt-1/PlGF ratio were performed. Placental histology was evaluated blinded according to the Amsterdam Consensus criteria. Results: Placental lesions with maternal vascular malperfusion (MVM) were significantly more frequent in HDP-FGR and early FGR (92% and 83%). MVM were significantly associated with abnormal feto-placental Doppler parameters, especially in early FGR. Delayed villous maturation (DVM) was associated with late FGR (83%). HDP-AGA fetus cases presented a heterogeneous pattern of placental lesions, including 60% of cases with MVM, but were not associated with abnormal Doppler feto-placental velocimetry. Conclusions: We found a prevalence of placental maternal vascular malperfusion in HDP-FGR and early FGR groups. These lesions were also associated with abnormal, anti-, and angiogenic markers. Conversely HDP-AGA fetus and late FGR presented more heterogeneous placental lesions not severe enough to cause feto-placental Doppler anomalies. These conditions are likely associated with different etiologies, such as maternal pre-pregnancy risk factors for metabolic syndrome. These findings suggest a possible preventive nutritional approach in addition to low-dose aspirin in pregnant women with predisposing factors for HDP-AGA fetuses and late FGR.

SARS- CoV-2 infection and oxidative stress in early-onset preeclampsia

SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) also in pregnant women. Infection in pregnancy leads to maternal and placental functional alterations. Pregnant women with vascular defects such as preeclampsia show high susceptibility to SARS-CoV-2 infection by undefined mechanisms. Pregnant women infected with SARS-CoV-2 show higher rates of preterm birth and caesarean delivery, and their placentas show signs of vasculopathy and inflammation. It is still unclear whether the foetus is affected by the maternal infection with this virus and whether maternal infection associates with postnatal affections. The SARS-CoV-2 infection causes oxidative stress and activation of the immune system leading to cytokine storm and next tissue damage as seen in the lung. The angiotensin-converting-enzyme 2 expression is determinant for these alterations in the lung. Since this enzyme is expressed in the human placenta, SARS-CoV-2 could infect the placenta tissue, although reported to be of low frequency compared with maternal lung tissue. Early-onset preeclampsia (eoPE) shows higher expression of ADAM17 (a disintegrin and metalloproteinase 17) causing an imbalanced renin-angiotensin system and endothelial dysfunction. A similar mechanism seems to potentially account for SARS-CoV-2 infection. This review highlights the potentially common characteristics of pregnant women with eoPE with those with COVID-19. A better understanding of the mechanisms of SARS-CoV-2 infection and its impact on the placenta function is determinant since eoPE/COVID-19 association may result in maternal metabolic alterations that might lead to a potential worsening of the foetal programming of diseases in the neonate, young, and adult.

The etiology of preeclampsia

Preeclampsia is one of the "great obstetrical syndromes" in which multiple and sometimes overlapping pathologic processes activate a common pathway consisting of endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. This article reviews the potential etiologies of preeclampsia. The role of uteroplacental ischemia is well-established on the basis of a solid body of clinical and experimental evidence. A causal role for microorganisms has gained recognition through the realization that periodontal disease and maternal gut dysbiosis are linked to atherosclerosis, thus possibly to a subset of patients with preeclampsia. The recent reports indicating that SARS-CoV-2 infection might be causally linked to preeclampsia are reviewed along with the potential mechanisms involved. Particular etiologic factors, such as the breakdown of maternal-fetal immune tolerance (thought to account for the excess of preeclampsia in primipaternity and egg donation), may operate, in part, through uteroplacental ischemia, whereas other factors such as placental aging may operate largely through syncytiotrophoblast stress. This article also examines the association between gestational diabetes mellitus and maternal obesity with preeclampsia. The role of autoimmunity, fetal diseases, and endocrine disorders is discussed. A greater understanding of the etiologic factors of preeclampsia is essential to improve treatment and prevention.

Preeclampsia and eclampsia: the conceptual evolution of a syndrome

Preeclampsia, one of the most enigmatic complications of pregnancy, is considered a pregnancy-specific disorder caused by the placenta and cured only by delivery. This article traces the condition from its origins-once thought to be a disease of the central nervous system, recognized by the occurrence of seizures (ie, eclampsia)-to the present time when preeclampsia is conceptualized primarily as a vascular disorder. We review the epidemiologic data that led to the recommendation to use diastolic hypertension and proteinuria as diagnostic criteria, as their combined presence was associated with an increased risk of fetal death and the birth of small-for-gestational-age neonates. However, preeclampsia is a multisystemic disorder with protean manifestations, and the condition can be present even in the absence of hypertension and proteinuria. Toxins gaining access to the maternal circulation have been proposed to mediate the clinical manifestations-hence, the term "toxemia of pregnancy," which was used for several decades. The search for putative toxins has challenged investigators for more than a century, and a growing body of evidence suggests that products of an ischemic or a stressed placenta are responsible for the vascular changes that characterize this syndrome. The discovery that the placenta can produce antiangiogenic factors, which regulate endothelial cell function and induce intravascular inflammation, has been a major step forward in the understanding of preeclampsia. We view the release of antiangiogenic factors by the placenta as an adaptive response to improve uterine perfusion by modulating endothelial function and maternal cardiovascular performance. However, this homeostatic response can become maladaptive and lead to damage of target organs during pregnancy or the postpartum period. Early-onset preeclampsia has many features in common with atherosclerosis, whereas late-onset preeclampsia seems to result from a mismatch of fetal demands and maternal supply, that is, a metabolic crisis. Preeclampsia, as it is understood today, is essentially vascular dysfunction unmasked or caused by pregnancy. A subset of patients diagnosed with preeclampsia are at greater risk of the subsequent development of hypertension, ischemic heart disease, heart failure, vascular dementia, and end-stage renal disease. However, these adverse events may be the result of a preexisting vascular pathologic process; it is not known if the occurrence of preeclampsia increases the baseline risk. Therefore, the understanding, prediction, prevention, and treatment of preeclampsia are healthcare priorities.

Uterine Artery Pulsatility Index as a Pre-eclampsia Predictor in the 3 Trimesters in Women with Singleton Pregnancies

OBJECTIVE

 To evaluate the mean uterine artery pulsatility index (UtAPI) in each trimester of pregnancy as a predictor of early or late pre-eclampsia (PE) in Colombian pregnant women.

METHODS

 The UtAPI was measured in singleton pregnancies in each trimester. Uterine artery pulsatility index as predictor of PE was evaluated by odds ratio (OR), receiver operating characteristic (ROC) curves, and Kaplan-Meier diagram.

RESULTS

 Analysis in the 1^st and 3^rd trimester showed that abnormal UtAPI was associated with early PE (OR: 5.99: 95% confidence interval [CI]: 1.64-21.13; and OR: 10.32; 95%CI: 2.75-42.49, respectively). Sensitivity and specificity were 71.4 and 79.6%, respectively, for developing PE (area under the curve [AUC]: 0.922). The Kaplan-Meier curve showed that a UtAPI of 0.76 (95%CI: 0.58-1.0) in the 1^st trimester was associated with early PE, and a UtAPI of 0.73 (95%CI: 0.55-0.97) in the 3^rd trimester was associated with late PE.

CONCLUSION

 Uterine arteries proved to be a useful predictor tool in the 1^st and 3^rd trimesters for early PE and in the 3^rd trimester for late PE in a pregnant population with high prevalence of PE.

Placental Findings in Preterm and Term Preeclampsia: An Integrative Review of the Literature

INTRODUCTION

 Preeclampsia (PE) is a pregnancy complication associated with increased maternal and perinatal morbidity and mortality. The disease presents with recent onset hypertension (after 20 weeks of gestation) and proteinuria, and can progress to multiple organ dysfunction, with worse outcomes among early onset preeclampsia (EOP) cases (< 34 weeks). The placenta is considered the root cause of PE; it represents the interface between the mother and the fetus, and acts as a macromembrane between the two circulations, due to its villous and vascular structures. Therefore, in pathological conditions, macroscopic and microscopic evaluation can provide clinically useful information that can confirm diagnosis and enlighten about outcomes and future therapeutic benefit.

OBJECTIVE

 To perform an integrative review of the literature on pathological placental findings associated to preeclampsia (comparing EOP and late onset preeclampsia [LOP]) and its impacts on clinical manifestations.

RESULTS

 Cases of EOP presented worse maternal and perinatal outcomes, and pathophysiological and anatomopathological findings were different between EOP and LOP placentas, with less placental perfusion, greater placental pathological changes with less villous volume (villous hypoplasia), greater amount of trophoblastic debris, syncytial nodules, microcalcification, villous infarcts, decidual arteriolopathy in EOP placentas when compared with LOP placentas. Clinically, the use of low doses of aspirin has been shown to be effective in preventing PE, as well as magnesium sulfate in preventing seizures in cases of severe features.

CONCLUSION

 The anatomopathological characteristics between EOP and LOP are significantly different, with large morphological changes in cases of EOP, such as hypoxia, villous infarctions, and hypoplasia, among others, most likely as an attempt to ascertain adequate blood flow to the fetus. Therefore, a better understanding of the basic macroscopic examination and histological patterns of the injury is important to help justify outcomes and to determine cases more prone to recurrence and long-term consequences.

Role of Uterine Artery Doppler Ultrasound in Predicting Pre-Eclampsia in High-Risk Women

Background and objective

Pre-eclampsia (PE) is a major cause of maternal morbidity and mortality. The utility of Doppler ultrasonography (U/S) in predicting PE has not been extensively explored. This study aimed to determine the role of Doppler U/S in predicting PE among high-risk women.

Methodology

This was a retrospective observational study conducted at the Department of Obstetrics and Gynecology of Abbasi Shaheed Hospital in Karachi, over a period of one year, from January 2019 till December 2019. A total of 325 women were initially screened for risk factors for PE. Among them, 75 women were eventually found to have risk factors for PE and hence included in the study. Uterine artery Doppler U/S was performed to evaluate uterine artery’s flow velocity waveforms. They were then used to calculate the presence of diastolic notch and resistance index (RI). At each antenatal visit, the risk factors for PE such as BP, proteinuria, and signs and symptoms were noted. Women were labeled to have PE if they developed hypertension (BP >140/90) after 20 weeks of gestation in combination with proteinuria.

Results

Twenty women (28%) had a normal Doppler flow of the uterine arteries. In 54 (72%) women, a unilateral/bilateral RI >0.58 was observed, and 29 women (38.7%) had a bilateral Rl >0.58. Notching of the uterine artery was also observed in 42 (26.7%, unilateral/bilateral) and in 22 (29.3%) bilaterally. Among the 75 women, BP of 140/90 mmHg along with proteinuria was observed in 56 (76.7%) cases, which were hence diagnosed as PE. Based on the cutoff of Rl and notching of the uterine artery, the overall sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of Doppler U/S in predicting PE were 71.4%, 26.3%, 23.8%, and 74.1%, respectively. As far as individual Doppler U/S indices were concerned, RI >0.58 (unilateral/bilateral) was found to be most sensitive (71%), while the presence of uterine artery notch (unilateral/bilateral) was most specific in predicting PE.

Conclusion

Abnormal Doppler U/S has good overall sensitivity in predicting PE. Among individual Doppler indices, notching of uterine arteries had a better specificity compared to high RI.

Ultrasound in the first trimester of pregnancy

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Oxidative stress and mitochondrial dysfunction in early-onset and late-onset preeclampsia

Preeclampsia is a pregnancy-specific syndrome with multisystem involvement which leads to foetal, neonatal, and maternal morbidity and mortality. This syndrome is characterized by the onset of clinical signs and symptoms and delivery before (early-onset preeclampsia, eoPE), or after (late-onset preeclampsia, loPE), the 34 weeks of gestation. Preeclampsia is a mitochondrial disorder where its differential involvement in eoPE and loPE is unclear. Mitochondria regulate cell metabolism and are a significant source of reactive oxygen species (ROS). The syncytiotrophoblast in eoPE and loPE show altered mitochondrial structure and function resulting in ROS overproduction, oxidative stress, and cell damage and death. Mitochondrial dysfunction in eoPE may result from altered expression of several molecules, including dynamin-related protein 1 and mitofusins, compared with loPE where these factors are either reduced or unaltered. Equally, mitochondrial fusion/fission dynamics seem differentially modulated in eoPE and loPE. It is unclear whether the electron transport chain and oxidative phosphorylation are differentially altered in these two subgroups of preeclampsia. However, the activity of complex IV (cytochrome c oxidase) and the expression of essential proteins involved in the electron transport chain are reduced, leading to lower oxidative phosphorylation and mitochondrial respiration in the preeclamptic placenta. Interventional studies in patients with preeclampsia using the coenzyme Q₁₀, a key molecule in the electron transport chain, suggest that agents that increase the antioxidative capacity of the placenta may be protective against preeclampsia development. In this review, the mitochondrial dysfunction in both eoPE and loPE is summarized. Therapeutic approaches are discussed in the context of contributing to the understanding of mitochondrial dysfunction in eoPE and loPE.

Characterizing placental stiffness using ultrasound shear-wave elastography in healthy and preeclamptic pregnancies

PURPOSE

To measure the stiffness of the placenta in healthy and preeclamptic patients in the second and third trimesters of pregnancy using ultrasound shear-wave elastography (SWE). We also aimed to evaluate the effect of age, gestational age, gravidity, parity and body mass index (BMI) on placental stiffness and a possible correlation of stiffness with perinatal outcomes.

METHODS

In a case-control study, we recruited a total of 47 singleton pregnancies in the second and third trimesters of which 24 were healthy and 23 were diagnosed with preeclampsia. In vivo placental stiffness was measured once at the time of recruitment for each patient. Pregnancies with posterior placentas, multiple gestation, gestational hypertension, chronic hypertension, diabetes, autoimmune disease, fetal growth restriction and congenital anomalies were excluded.

RESULTS

The mean placental stiffness was significantly higher in preeclamptic pregnancies compared to controls in the third trimester (difference of means = 16.8; 95% CI (9.0, 24.5); P < 0.001). There were no significant differences in placental stiffness between the two groups in the second trimester or between the severe preeclampsia and preeclampsia without severe features groups (difference of means = 9.86; 95% CI (-5.95, 25.7); P ≥ 0.05). Peripheral regions of the placenta were significantly stiffer than central regions in the preeclamptic group (difference of means = 10.67; 95% CI (0.07, 21.27); P < 0.05), which was not observed in the control group (difference of means = 0.55; 95% CI (- 5.25, 6.35); P > 0.05). We did not identify a correlation of placental stiffness with gestational age, maternal age, gravidity or parity. However, there was a statistically significant correlation with BMI (P < 0.05). In addition, pregnancies with higher placental stiffness during the 2nd and 3rd trimesters had significantly reduced birth weight (2890 ± 176 vs. 2420 ± 219 g) and earlier GA (37.8 ± 0.84 vs. 34.3 ± 0.98 weeks) at delivery (P < 0.05).

CONCLUSION

Compared to healthy pregnancies, placentas of preeclamptic pregnancies are stiffer and more heterogeneous. Placental stiffness is not affected by gestational age or the severity of preeclampsia but there is a correlation with higher BMI and poor perinatal outcomes.

Effect of previous cesarean sections on second-trimester uterine artery Doppler

AIM

In this study, we investigated the effects of previous cesarean sections on uterine artery Doppler indices.

METHODS

This prospective cohort study included 153 healthy pregnant women between 18 and 24 weeks of gestation. Seventy-three pregnant women without previous cesarean sections (control group) and 80 pregnant women with previous cesarean sections (study group) were compared in terms of uterine artery Doppler indices.

RESULTS

The mean uterine artery pulsatility index (PI) MoM value was 1.18 ± 0.40 in the study group and 1.07 ± 0.35 in the control group (P = 0.046). The number of patients with uterine artery PI values above 95 percentile was 18 (22.5%) in the study group and 5(6.8%) in the control group (P = 0.007). The mean gestational age at birth was significantly lower in the study group (38.2 ± 1.3 vs. 39 ± 1.0, P < 0.001). There was no significant difference between the mean PI, resistance index (RI) and systolic/diastolic (S/D) ratio values of the uterine artery (P = 0.16, 0.11, 0.08, respectively). When the comparison was made with the number of previous cesarean sections, all three index values of the patients who had had more than two cesarean sections were found to be significantly higher.

CONCLUSION

The Doppler flow indices of the uterine artery significantly increased in patients with more than two previous cesarean sections. When evaluating uterine artery Doppler indices in pregnant women with a history of previous cesarean sections, these factors should be considered.

Does low-dose aspirin initiated before 11 weeks' gestation reduce the rate of preeclampsia?

OBJECTIVE DATA

Preconception or early administration of low-dose aspirin might improve endometrial growth, placental vascularization, and organogenesis. Most studies have evaluated the potential benefit of preconception or early administration of low-dose aspirin in women with a history of recurrent pregnancy loss, women who have undergone in vitro fertilization, or women with thrombophilia or antiphospholipid syndrome. These women are at an increased risk of placenta-associated complications of pregnancy, including preeclampsia, preterm delivery, and fetal growth restriction.

STUDY OUTCOMES

We performed a systematic review and meta-analysis to evaluate the effect of low-dose aspirin initiated at <11 weeks' gestation on the risk of preeclampsia, gestational hypertension, or any hypertensive disorder of pregnancy. Secondary outcomes included preterm delivery at <37 weeks' gestation and fetal growth restriction.

STUDY APPRAISAL AND SYNTHESIS METHODS

We searched in MEDLINE via PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from 1985 to November 2018. Entry criteria were randomized controlled trials evaluating the effect of aspirin administered at <11 weeks' gestation in preventing preeclampsia and/or hypertensive disorders in pregnancy or improving pregnancy outcomes in women with recurrent miscarriage as compared with placebo or no treatment and outcome data available or provided by authors for >85% of the study population. Relative risks with 95% confidence intervals were calculated for each study and pooled for global analysis as the effect measure. We assessed statistical heterogeneity in each meta-analysis using the χ² statistics, I², and Tau². Heterogeneity was considered substantial if an I² was greater than 50% and either the Tau² was greater than zero or there was a low P value (<0.10) in the χ² test for heterogeneity. Random-effects meta-analysis, weighted by the size of the studies, was performed to produce an overall summary on aspirin effect for each outcome. Sensitivity analysis by sequential omission of each individual study and by fixed-effects model was performed. Publication bias was not assessed because of the small number of included studies. Statistical analysis was performed using Stata release 14.0 (StataCorp).

RESULTS

The entry criteria were fulfilled by 8 randomized controlled trials on a combined total of 1426 participants. Low-dose aspirin initiated at <11 weeks' gestation was associated with a nonsignificant reduction in the risk of preeclampsia (relative risk, 0.52; 95% confidence interval, 0.23-1.17, P = .115), gestational hypertension (relative risk, 0.49; 95% confidence interval, 0.20-1.21; P = .121), and any hypertensive disorder of pregnancy (relative risk, 0.59; 95% confidence interval, 0.33-1.04, P = .067). Early administration of low-dose aspirin reduced the risk of preterm delivery (relative risk, 0.52; 95% confidence interval, 0.27-0.97, P = .040) but had no impact on the risk of fetal growth restriction (relative risk, 1.10; 95% confidence interval, 0.58-2.07, P = .775). Except for preterm delivery and any hypertensive disorder of pregnancy, sensitivity analysis demonstrated similar observations, therefore confirming the robustness of the analysis.

CONCLUSION

The administration of low-dose aspirin at <11 weeks' gestation in women at high risk does not decrease the risk of preeclampsia, gestational hypertension, any hypertensive disorder of pregnancy, and fetal growth restriction. However, it might reduce the risk of preterm delivery. Larger randomized controlled trials will be required to substantiate the findings.

The Placenta as a Window to Maternal Vascular Health

Cardiovascular disease remains the leading killer of women, with sex-specific manifestation, mechanisms, and morbidity. Preeclampsia, fetal growth restriction, and a subset of preterm births demonstrate aberrancies in the maternal vessels supplying the placenta and damage to the placental parenchyma consistent with hypoxic/ischemic or oxidative injury. This constellation of findings, maternal vascular malperfusion (MVM) lesions, may hold the key to understanding and identifying the elevated risk for early cardiovascular disease in women who experience adverse pregnancy outcomes. This intriguing possibility has only begun to be examined, but accumulating evidence is compelling and is reviewed here.

The Placental Basis of Fetal Growth Restriction

Placental dysfunction is a major contributing factor to fetal growth restriction. Placenta-mediated fetal growth restriction occurs through chronic fetal hypoxia owing to poor placental perfusion through a variety of mechanisms. Maternal vascular malperfusion is the most common placental disease contributing to fetal growth restriction; however, the role of rare placental diseases should not be overlooked. Although the features of maternal vascular malperfusion are identifiable on placental pathology, antepartum diagnostic methods are evolving. Placental imaging and uterine artery Doppler, used in conjunction with angiogenic growth factors (specifically placenta growth factor and soluble fms-like tyrosine kinase-1), play an increasingly important role.

Distinctive patterns of placental lesions in pre-eclampsia vs small-for-gestational age and their association with fetoplacental Doppler

OBJECTIVES

To describe placental histopathological findings in a large cohort of pregnancies complicated by pre-eclampsia (PE) and/or small-for-gestational age (SGA), and to investigate their association with fetoplacental Doppler parameters.

METHODS

This was a prospective observational study of normotensive pregnancies with SGA (defined as birth weight < 10^th centile) (n = 184), PE pregnancies with a normally grown fetus (n = 102), pregnancies with both PE and SGA (n = 120) and uncomplicated pregnancies (n = 202). Uterine (UtA), umbilical (UA) and fetal middle cerebral (MCA) artery pulsatility indices (PI) were assessed. The cerebroplacental ratio (CPR) was calculated by dividing MCA-PI by UA-PI. Doppler parameters were considered abnormal when UtA-PI or UA-PI was > 95^th centile or MCA-PI or CPR was < 5^th centile. Placental lesions were categorized as vascular (maternal or fetal side), immunoinflammatory or other, according to the 2014 Amsterdam Placental Workshop Group Consensus Statement. Comparison between the study groups was performed using univariate and multiple regression analysis, and logistic regression was used to determine the relationship between abnormal Doppler parameters and placental lesions.

RESULTS

Maternal-side vascular lesions were significantly more common in PE pregnancies with SGA than in the other groups (PE + SGA, 73% vs PE, 46% vs SGA, 38% vs controls, 31%; P = 0.01) and included mainly two types of lesion: developmental (PE + SGA, 13% vs PE, 5% vs SGA, 3% vs controls, 1.5%; P < 0.001) and malperfusion (PE + SGA, 70% vs PE, 39% vs SGA, 32% vs controls, 25%; P = 0.001). In contrast, the incidence of fetal-side developmental lesions was significantly higher in normotensive SGA pregnancies than in controls and PE pregnancies (PE + SGA, 0% vs PE, 3% vs SGA, 8% vs controls, 2%; P = 0.001). All cases displayed a lower prevalence of infectious lesions than did controls, with the highest prevalence of immune lesions observed in pregnancies with both PE and SGA (PE + SGA, 18% vs PE, 8% vs SGA, 10% vs controls, 9%; P = 0.001). All fetoplacental Doppler parameters evaluated were associated with maternal-side vascular lesions, mainly malperfusion (mean UtA-PI: odds ratio (OR), 2.45 (95% CI, 1.51-3.97); UA-PI: OR, 2.05 (95% CI, 1.02-4.47); MCA-PI: OR, 2.75 (95% CI, 1.40-5.42); CPR: OR, 1.75 (95% CI, 1.04-2.95)). This association was evident mainly in the normotensive SGA group, being non-significant in controls or PE pregnancies without SGA. No significant associations were observed between fetoplacental Doppler parameters and other placental lesions in any of the study groups.

CONCLUSIONS

PE and SGA are associated with different patterns of placental histopathological lesions in accordance with the clinical manifestation of the placental disorder (maternal vs fetal). Fetoplacental Doppler findings show an association with placental malperfusion lesions on the maternal side, supporting the use of abnormal Doppler as a surrogate for placental insufficiency. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Pre-eclampsia: pathophysiology and clinical implications

Pre-eclampsia is a common disorder that particularly affects first pregnancies. The clinical presentation is highly variable but hypertension and proteinuria are usually seen. These systemic signs arise from soluble factors released from the placenta as a result of a response to stress of syncytiotrophoblast. There are two sub-types: early and late onset pre-eclampsia, with others almost certainly yet to be identified. Early onset pre-eclampsia arises owing to defective placentation, whilst late onset pre-eclampsia may center around interactions between normal senescence of the placenta and a maternal genetic predisposition to cardiovascular and metabolic disease. The causes, placental and maternal, vary among individuals. Recent research has focused on placental-uterine interactions in early pregnancy. The aim now is to translate these findings into new ways to predict, prevent, and treat pre-eclampsia.

Comparative Study of Abdominal Versus Transvaginal Ultrasound for Uterine Artery Doppler Velocimetry at 11 to 13 Weeks

OBJECTIVES

To compare the first-trimester uterine artery pulsatility index (PI) measured by abdominal and transvaginal ultrasound (US).

METHODS

We performed a prospective study of singleton pregnant women recruited at 11 to 13 weeks' gestation. The mean uterine artery PI was obtained by abdominal followed by transvaginal US. The mean of the left and right uterine artery PIs was used, and differences between approaches were computed. The intraclass correlation coefficient and a Bland-Altman plot were used to compare the two approaches.

RESULTS

Data were available for 940 participants, including 928 (99%) with uterine artery PIs obtained on both uterine sides. The mean uterine artery PI decreased with gestational age in both approaches (P < .001). We observed a moderate correlation between abdominal and transvaginal mean uterine artery PIs (intraclass correlation coefficient, 0.72; 95% confidence interval, 0.69 to 0.75). Values obtained by abdominal US (median, 1.70, interquartile range, 1.35 to 2.09) were greater than those obtained by transvaginal US (median, 1.65; interquartile range, 1.37 to 1.99). There was a significant increase in differences as average measurements became higher (P < .01).

CONCLUSIONS

The first-trimester mean uterine artery PI decreases with gestational age in both approaches. Abdominal US could be associated with greater uterine artery PI values than transvaginal US, especially at higher measurements. The first-trimester uterine artery PI for prediction of adverse perinatal outcomes should be adjusted for gestational age and possibly for the US approach.

Analysis of hepatocyte growth factor immunostaining in the placenta of HIV-infected normotensive versus preeclamptic pregnant women

OBJECTIVE

Hepatocyte Growth Factor (HGF) plays a role in the migration and morphogenesis of different cell types and tissues. Preeclampsia (PE) is associated with deficient trophoblast invasion and placental insufficiency; hence HGF production is expected to be compromised. This study therefore aimed to immunolocalize and morphometrically analyse placental HGF in normotensive versus PE pregnancies stratified by HIV status and gestational age.

STUDY DESIGN

Normotensive (N; n = 40) and preeclamptic (PE; n = 80) women were stratified by HIV status (HIV- and HIV+), and gestational age i.e. early onset of PE (EOPE; <34 weeks) and late onset of PE (LOPE; ≥34 weeks). Placental tissues were stained using conventional immunohistochemistry, performed using mouse anti-human HGF antibody. Morphometric image analysis was performed using Zeiss Axio-Vision software.

RESULTS

HGF was immuno-localized within the syncytiotrophoblast, cytotrophoblast, endothelial and fibroblast-like cell populations of both conducting and exchange villi. Based on pregnancy type, HGF immunoexpression within the conducting villi was significantly different between Nvs EOPE (p = 0.0372) and EOPE vs LOPE (p = 0.0006). Within the exchange villi, no significant difference of HGF immunostaining was noted between N vs EOPE and N vs LOPE. A down-regulation of HGF immuno-expression was observed in LOPE compared to other groups within both villi types, albeit non-significant. Based on HIV status, no significant difference in HGF immuno-expression was demonstrated between HIV- vs HIV + within the exchange and conducting villi. However, the expression of HGF in HIV- group was elevated in both villi types. Across the groups, a significant difference was found between N+ vs EOPE- (p  = 0.0207), EOPE+ vs LOPE- (p = 0.0036) and EOPE- vs LOPE- (p = 0.0016) of the conducting villi while no significant difference was found within the exchange villi.

CONCLUSION

This novel study demonstrates that HGF was two-fold higher in conducting compared to exchange villi irrespective of the pregnancy type. HIV infection does not influence HGF expression within the conducting and exchange villi. The HGF/c-MET receptor complex may modulate the ligand expression within the placenta.

Perinatal outcome and placental apoptosis in patients with late-onset pre-eclampsia and abnormal uterine artery Doppler at diagnosis

OBJECTIVE

To determine the rate of placental apoptosis and adverse perinatal outcome in patients with late-onset pre-eclampsia (PE) and abnormal uterine artery (UtA) Doppler at diagnosis.

METHODS

This was a prospective cohort study of women with singleton pregnancy diagnosed with late PE, performed between August 2011 and January 2014 at the Maternal-Fetal Medicine Unit of Hospital Carlos Van Buren. Patients were stratified according to UtA Doppler status at diagnosis (pulsatility index (PI) ≤ or > 95^th percentile). Logistic regression analysis was performed to identify associations between abnormal UtA Doppler and adverse maternal and perinatal outcomes. In a subset of this cohort for whom placental samples were available, immunohistochemical analysis of the placenta was performed to identify the rate of apoptosis and its association with UtA Doppler by comparing samples from those with normal and those with abnormal UtA Doppler and normotensive controls. Non-parametric linear trend analysis was performed for assessment of the apoptotic index.

RESULTS

Eighty-six patients were included in the final analysis. Of these, UtA-PI was above the 95^th percentile in 33 (38.4%) patients. Gestational age at diagnosis and delivery were significantly lower in this group compared with patients with normal UtA Doppler. Abnormal UtA Doppler was associated with increased risk of severe PE (odds ratio (OR) = 7.5; 95% CI, 2.76-20.46; P < 0.001), late preterm delivery (OR = 13.7; 95% CI, 4.53-41.46; P < 0.001), small-for-gestational age at birth (OR = 12.3; 95% CI, 3.17-47.57; P < 0.001) and admission to the neonatal intensive care unit (OR = 12.8; 95% CI, 2.61-62.36; P = 0.002). Moreover, UtA Z-score demonstrated a significant inverse correlation with birth-weight Z-score (r = -0.34; P = 0.0013). Mean placental apoptotic index demonstrated an ascending linear trend according to UtA Doppler status (P = 0.04).

CONCLUSIONS

In patients with late PE, UtA Doppler was useful for clinical classification and as an indicator of placental histological findings. Correlation between UtA Doppler and the apoptotic index provides new evidence of a subgroup of late PE with a placental origin. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Ophthalmic artery Doppler for prediction of pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

To determine the accuracy of ophthalmic artery Doppler in pregnancy for the prediction of pre-eclampsia (PE).

METHODS

MEDLINE, EMBASE, CINAHL and The Cochrane Library were searched for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of ophthalmic artery Doppler to predict the development of PE and extracted data to construct 2 × 2 tables. Individual patient data were obtained from the authors if available. A bivariate random-effects model was used for the quantitative synthesis of data. Logistic regression analysis was employed to generate receiver-operating characteristics (ROC) curves and obtain optimal cut-offs for each investigated parameter, and a bivariate analysis was employed using predetermined cut-offs to obtain sensitivity and specificity values and generate summary ROC curves.

RESULTS

A total of 87 citations matched the search criteria of which three studies, involving 1119 pregnancies, were included in the analysis. All included studies had clear description of the index and reference tests, avoidance of verification bias and adequate follow-up. Individual patient data were obtained for all three included studies. First diastolic peak velocity of ophthalmic artery Doppler at a cut-off of 23.3 cm/s showed modest sensitivity (61.0%; 95% CI, 44.2-76.1%) and specificity (73.2%; 95% CI, 66.9-78.7%) for the prediction of early-onset PE (area under the ROC curve (AUC), 0.68; 95% CI, 0.61-0.76). The first diastolic peak velocity had a much lower sensitivity (39.0%; 95% CI, 20.6-61.0%), a similar specificity (73.2%; 95% CI, 66.9-78.7%) and a lower AUC (0.58; CI, 0.52-0.65) for the prediction of late-onset PE. The pulsatility index of the ophthalmic artery did not show a clinically useful sensitivity or specificity at any cut-off for early- or late-onset PE. Peak ratio above 0.65 showed a similar diagnostic accuracy to that of the first diastolic peak velocity with an AUC of 0.67 (95% CI, 0.58-0.77) for early-onset PE and 0.57 (95% CI, 0.51-0.63) for late-onset disease.

CONCLUSIONS

Ophthalmic artery Doppler is a simple, accurate and objective technique with a standalone predictive value for the development of early-onset PE equivalent to that of uterine artery Doppler evaluation. The relationship between ophthalmic Doppler indices and PE cannot be a consequence of trophoblast invasion and may be related to maternal hemodynamic adaptation to pregnancy. The findings of this review justify efforts to elucidate the effectiveness and underlying mechanism whereby two seemingly unrelated maternal vessels can be used for the prediction of a disease considered a 'placental disorder'. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Correlation Between Fetal Weight Gain and Birth Weight with Blood Flow in the Uterine Arteries Calculated with the PixelFlux Technique

Introduction

The aim was to investigate correlations between fetal weight gain/day and birthweight with blood flow estimates in the uterine arteries calculated with the PixelFlux technique and with measurements from TAmax. We also aimed to examine the agreement between estimates using the two methods.

Material and methods

We conducted a prospective observational pilot study in pregnancy week 24-25 in women with risk pregnancies referred to the fetal medical centre at St. Olavs Hospital, Trondheim, Norway from March 2016 to June 2016. Blood flow in the uterine arteries was calculated using time-averaged peak velocity (TAmax) and the PixelFlux technique. PixelFlux is a method based on pixelwise calculation of spatially angle-corrected velocities and areas of all pixels inside a vessel during a heart cycle.

Results

The mean flow calculated from PixelFlux and TAmax was 811 ml/minute and 787 ml/minute, respectively. The intra-class correlation coefficient was 0.83 (95% CI 0.72-0.90) and limits of agreement were -441 ml/minute (95% CI -558 to -324 ml/minute) to 489 ml/minute (95% CI 372 to 606 ml/minute). We observed a significant correlation between mean flow calculated from PixelFlux and birthweight (r=0.41; p<0.01) and between flow calculated from PixelFlux and weight gain/day (r=0.33; p=0.02). Calculation based on TAmax was significant correlated to birthweight (r=0.34; p=0.02), but not to weight-gain/day. Pulsatile index was not correlated to flow, birthweight or fetal weight-gain/day.

Conclusions

We found significant correlations between estimated blood flow in the uterine arteries using the PixelFlux technique with fetal weight-gain/day and with birthweight. Estimates from two methods showed good agreement.

Italian Advisory Board: sFlt-1/PlGF ratio and preeclampsia, state of the art and developments in diagnostic, therapeutic and clinical management

Extensive research has been published, showing the usefulness of angiogenic markers in both diagnosis and subsequent prediction and management of preeclampsia and placenta-related disorders. Recent evidence provides a helpful cut off for the Elecsys ratio sFlt-1 to PlGF, that predicts preeclampsia development in women with sign and symptoms, before its clinical onset in the short term. In Europe, no accordance exists for the use of such kind of test in clinical practice; only German guidelines have recently taken it into account, as a diagnostic aid for preeclampsia, in conjunction with other clinical findings. This panel of Italian experts recently met, in order to review the literature and to promote the evaluation of the clinical utility of sFlt-1/PlGF ratio at the Italian country level, as regards: prediction of preeclampsia during the first trimester, prediction or exclusion of new onset or recurrence in patients with risk factors for preeclampsia, triage of patients suffering from gestational hypertension, evaluation of disease severity, prediction of adverse maternal and fetal outcomes.