A new, clinically oriented, unifying and simple placental classification system

Characterising delayed villous maturation: A narrative literature review

The normal development of the placenta is vital for fetal growth and a healthy pregnancy outcome. Delayed villous maturation (DVM) is a placental lesion that has been implicated in stillbirth. In DVM, villi do not maturate adequately for their gestational age. DVM is characterised by larger and fewer terminal placental villi, low numbers of syncytial knots, and thicker and fewer vasculosyncytial membranes. DVM is most commonly reported in conjunction with maternal diabetes; however, the occurrence of idiopathic DVM suggests that there may be multiple mechanistic pathways that contribute to DVM. DVM can only be diagnosed through histopathological examination after birth, and there is significant interobserver variability in diagnosis. Establishing objective criteria to distinguish between DVM and healthy placentas is key to increasing the understanding of DVM. Vasculosyncytial membrane count, numbers of syncytial knots and CD15, among others, have been presented as potential diagnostic criteria in the literature. This review aims to compile information on DVM, including the pathophysiology, conditions that have reported associations with DVM and potential markers that could be used as criteria to differentiate between DVM and healthy placentas.

Transplacental passage of hyperforin, hypericin, and valerenic acid

Safe medications for mild mental diseases in pregnancy are needed. Phytomedicines from St. John’s wort and valerian are valid candidates, but safety data in pregnancy are lacking. The transplacental transport of hyperforin and hypericin (from St. John’s wort), and valerenic acid (from valerian) was evaluated using the ex vivo cotyledon perfusion model (4 h perfusions, term placentae) and, in part, the in vitro Transwell assay with BeWo b30 cells. Antipyrine was used for comparison in both models. U(H)PLC-MS/MS bioanalytical methods were developed to quantify the compounds. Perfusion data obtained with term placentae showed that only minor amounts of hyperforin passed into the fetal circuit, while hypericin did not cross the placental barrier and valerenic acid equilibrated between the maternal and fetal compartments. None of the investigated compounds affected metabolic, functional, and histopathological parameters of the placenta during the perfusion experiments. Data from the Transwell model suggested that valerenic acid does not cross the placental cell layer. Taken together, our data suggest that throughout the pregnancy the potential fetal exposure to hypericin and hyperforin – but not to valerenic acid – is likely to be minimal.

Placental Passage of Protopine in an Ex Vivo Human Perfusion System

The placental passage of protopine was investigated with a human ex vivo placental perfusion model. The model was first validated with diazepam and citalopram, 2 compounds known to cross the placental barrier, and antipyrine as a positive control. All compounds were quantified by partially validated U(H)PLC-MS/MS bioanalytical methods. Protopine was transferred from the maternal to the fetal circuit, with a steady-state reached after 90 min. The study compound did not affect placental viability or functionality, as glucose consumption, lactate production, and beta-human chorionic gonadotropin, and leptin release remained constant. Histopathological evaluation of all placental specimens showed unremarkable, age-appropriate parenchymal maturation with no pathologic findings.

Association of perinatal sentinel events, placental pathology and cerebral MRI in neonates with hypoxic-ischemic encephalopathy receiving therapeutic hypothermia

OBJECTIVE

Placental pathology might provide information on the etiology of hypoxic-ischemic encephalopathy (HIE). To evaluate the association of perinatal sentinel events (PSE), placental pathology and cerebral MRI in cooled neonates with moderate/severe HIE.

STUDY DESIGN

Retrospective analysis of 52 neonates with HIE registered in the Swiss National Asphyxia and Cooling Register 2011-2019. PSE and Non-PSE groups were tested for association with placental pathology. Placental pathology categories were correlated with MRI scores.

RESULTS

In total, 14/52 neonates (27%) had a PSE, 38 neonates (73%) did not have a PSE. There was no evidence for an association of occurrence of PSE and placental pathologies (p = 0.364). Neonates with high MRI scores tended to have more often chronic pathologies in their placentas than acute pathologies or normal placentas (p = 0.067).

CONCLUSION

Independent of the occurrence of PSE, chronic placental pathologies might be associated with more severe brain injury and needs further study.

Placental Passage of Humulone and Protopine in an Ex Vivo Human Perfusion System

The placental passage of humulone and protopine was investigated with a human ex vivo placental perfusion model. The model was first validated with diazepam and citalopram, 2 compounds known to cross the placental barrier, and antipyrine as a positive control. All compounds were quantified by partially validated U(H)PLC-MS/MS bioanalytical methods. Only a small portion of humulone initially present in the maternal circuit reached the fetal circuit. The humulone concentration in the maternal circuit rapidly decreased, likely due to metabolization in the placenta. Protopine was transferred from the maternal to the fetal circuit, with a steady-state reached after 90 min. None of the study compounds affected placental viability or functionality, as glucose consumption, lactate production, beta-human chorionic gonadotropin, and leptin release remained constant. Histopathological evaluation of all placental specimens showed unremarkable, age-appropriate parenchymal maturation with no pathologic findings.

Platelet alloimmunization is associated with low grade chronic histiocytic intervillositis - A new link to a rare placental lesion?

INTRODUCTION

Maternal alloimmunization against human platelet antigen (HPA)-1a has been implied to mediate both reduced birth weight and chronic placental inflammation. Fetal growth restriction is associated with different types of chronic inflammation in the placenta, mainly chronic histiocytic intervillositis and chronic villitis. The aim of this prospective study was to do a systematic examination of placentas from HPA-1a alloimmunized pregnancies, with focus on the histopathological and immunohistochemical diagnosis of variants of chronic inflammation.

MATERIAL AND METHODS

In a Polish-Norwegian study, 48 placentas were examined. The histopathology of placentas from 27 HPA-1a immunized women was compared with 21 placentas from non-immunized HPA-1a negative women (controls). In the group of alloimmunized women, ten received antenatal intravenous immunoglobulin G (IVIg). Tissue sections from formalin fixed paraffin embedded placental tissue were stained with hematoxylin and eosin and microscopically examined with focus on various types of chronic placental inflammations.

RESULTS

Chronic histiocytic intervillositis was observed in 40.7% of placentas from HPA-1a alloimmunized pregnancies, compared to none in the control group (p = 0.001). Chronic villitis of unknown etiology was more frequently found in the alloimmunized group, however this difference was not statistically significant. Maternal administration of IVIg did not seem to protect against chronic inflammatory lesions.

DISCUSSION

Placentas with detectable maternal anti-HPA-1a antibodies are associated with highly increased risk of low-grade chronic histiocytic intervillositis.

Circulating angiogenic profiles and histo-morphological placental characteristics of uncomplicated post-date pregnancies

INTRODUCTION

The objectives of this study were to describe the histo-morphology of post-date placentas in clinically uncomplicated pregnancies without adverse delivery outcomes and the association with maternal circulating pre-delivery Placental Growth Factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), as well as the sFlt-1/PlGF ratio.

METHODS

Post-date placentas (gestational week ≥40⁺², n = 87) were macroscopically and histo-morphologically assessed according to the international, standardized Amsterdam Workshop Consensus Group criteria. Inter-rater agreement was evaluated by percentage of agreement. PlGF and sFlt-1 concentrations were available from maternal serum sampled close to delivery, and were compared by Mann-Whitney U test. Linear regression analyses were adjusted for predefined potential confounders.

RESULTS

The majority of the post-date placentas showed morphological signs of delayed maturation. About half of the placentas showed increased syncytial knotting and fibrin. In placentas with increased presence of intervillous fibrin, median maternal PlGF level was significantly lower (p = 0.004), median sFlt-1 level higher and sFlt-1/PlGF ratio significantly higher (p = 0.002) compared to those with normal fibrin amounts. Increased placental syncytial knotting was associated with lower levels of PlGF, higher sFlt-1 and higher sFlt-1/PlGF ratio compared to those with normal knotting.

DISCUSSION

Our standardized morphological study of post-date placentas in clinically healthy women with uncomplicated pregnancies and delivery outcomes revealed delayed maturation in the majority of placentas. Increased pre-delivery circulating anti-angiogenic profile was associated with increased intervillous fibrin and syncytial knotting. We propose that circulating maternal angiogenic biomarkers may be of future use in clinical post-date pregnancy assessment, as they reflect important aspects of placental health and function.

Can information regarding the index stillbirth determine risk of adverse outcome in a subsequent pregnancy? Findings from a single-center cohort study

INTRODUCTION

Women with a history of stillbirth have an almost five-fold increased risk of stillbirth in a subsequent pregnancy, as well as increased risk of other adverse maternal and neonatal outcomes. The reasons for this association are not well understood but could relate to recurrent causes. We aimed to determine whether information from the time of index stillbirth, including cause, is associated with outcome of a subsequent pregnancy.

MATERIAL AND METHODS

A retrospective cohort study was conducted at a UK tertiary maternity center. Cases were included if stillbirth was investigated, subsequent pregnancy care was provided, and the birth occurred in the same unit. Data on maternal characteristics, findings of investigations, and classification of death using the ReCoDe system were extracted, and logistic regression was performed to determine whether these factors were associated with adverse outcome in the subsequent pregnancy.

RESULTS

In this cohort (n = 266), there were 69 adverse outcomes, including three perinatal deaths. Preterm delivery (16.2%) and birthweight <10th centile (12.4%) were the most common adverse outcomes. Of the preterm births, 69.8% were iatrogenic and 47% of these were due to abnormalities of fetal growth. On multivariate analysis women with a preexisting medical condition (adjusted odds ratio [aOR] 2.12, 95% CI 1.10-4.12) and those who smoked in their subsequent pregnancy (aOR 6.80, 95% CI 1.99-23.30) were at increased risk of adverse outcome. Neither ReCoDe classification of stillbirth (P = .61) nor gestation of stillbirth (P = .36) were associated with subsequent pregnancy outcome. Placental histopathological findings of maternal vascular malperfusion (aOR 11.34, 95% CI 2.20-58.62), fetal vascular malperfusion (aOR 9.27, 95% CI 1.09-78.82), and chorioamnionitis (aOR 6.35, 95% CI 1.16-34.78) in the index stillbirth were associated with adverse outcome in subsequent pregnancy. These associations were independent of maternal characteristics.

CONCLUSIONS

Placental examination at time of stillbirth is important, as certain placental disorders inform the risk of adverse outcome in subsequent pregnancy. In this cohort, information regarding maternal characteristics and classification of cause of stillbirth do not provide significant prognostic information about the risk of adverse outcome in subsequent pregnancies. Optimal management of maternal medical disorders and access to smoking cessation are essential.

Placental Morphology and Cellular Characteristics in Stillbirths in Women With Diabetes and Unexplained Stillbirths

CONTEXT.—

Women with diabetes have increased stillbirth risk. Although the underlying pathophysiological processes are poorly understood, stillbirth is frequently related to abnormal placental structure and function.

OBJECTIVE.—

To investigate placental morphology and cellular characteristics in the placentas of women with diabetes who had stillbirths and stillbirths of unexplained cause.

DESIGN.—

Placentas from women with uncomplicated live births, live births in women with diabetes, unexplained stillbirths, and stillbirths related to diabetes (n = 10/group) underwent clinical histopathologic assessment and were also investigated using immunohistochemical staining to quantify syncytial nuclear aggregates, proliferation, trophoblast area, vascularization, T cells, placental macrophages (Hofbauer cells), and the receptor for advanced glycation end products.

RESULTS.—

Ki67+ cells were decreased in unexplained stillbirths compared with live births in women with diabetes. Both stillbirth groups had increased cytokeratin 7+/nuclear area compared with controls. Blood vessels/villi were decreased in unexplained stillbirth compared with live births from women with diabetes. Compared with uncomplicated controls, CD163+ macrophages were increased in live births in women with diabetes and unexplained stillbirths, and further increased in stillbirths related to diabetes. There was no change in CD3+ T cells or syncytial nuclear aggregates. Receptor for advanced glycation end products-positive cells were decreased in both stillbirth groups compared with diabetes-related live births. Co-localization of receptor for advanced glycation end products in macrophages was increased in both stillbirth groups compared with live birth groups.

CONCLUSIONS.—

Stillbirths related to diabetes exhibit placental phenotypic differences compared with live births. Further investigation of these parameters may provide understanding of the pathologic mechanisms of stillbirth and aid the development of stillbirth prevention strategies.

Formulating a Meaningful and Comprehensive Placental Phenotypic Classification

INTRODUCTION

While many placental lesions have been identified and defined, the significance of multiple overlapping lesions has not been addressed. The purpose of our analysis was to evaluate overlapping patterns of placental pathology and determine meaningful phenotypes associated with adverse birth outcomes.

METHODS

Placental pathology reports were obtained from a single hospital between 2009 and 2018. Placental lesions were grouped into four major categories: acute inflammation (AI), chronic inflammation (CI), maternal vascular malperfusion (MVM), and fetal vascular malperfusion (FVM). Within each category, lesions were classified as not present, low grade or high grade. Combinations of pathologies were evaluated in relation to preterm birth (<37 weeks) and small for gestational age (SGA) infant (birthweight <10th percentile).

RESULTS

During the study period, 19,027 placentas were reviewed by pathologists. Results from interaction models indicate that MVM and MVM in combination with CI and/or FVM are associated with the greatest odds of SGA infant and PTB. When incorporating grade, we identified 21 phenotype groups, each with characteristic associations with the SGA infant and patterns of PTB.

DISCUSSION

We have developed a comprehensive and meaningful placental phenotype that incorporates severity and multiplicity of placental lesions. We have also developed a web application to facilitate phenotype determination (https://placentaexpression.shinyapps.io/phenotype).

Uteroplacental acute atherosis in preeclamptic pregnancies: Rates and clinical outcomes differ by tissue collection methods

OBJECTIVES

Acute atherosis (AA) is a uteroplacental spiral artery lesion, identified by intramural lipid-laden foam cells, with highest rates in preeclampsia (PE). We compared AA detection rates in preeclampsia (PE) across three different decidual spiral artery collection methods in same patients. We tested whether the rate and topographical distribution of AA associates with clinical parameters.

STUDY DESIGN

Three decidual tissue types were harvested from each of 107 preeclamptic women delivered by cesarean section. Routine sampled basal surface placenta (decidua basalis, DB) and fetal membrane roll (decidua parietalis, DP) biopsies were compared with decidual vacuum suction biopsies (DB), regarding spiral artery rate and AA presence. Spiral arteries and AA were identified using predefined, immunohistochemically based criteria on serial sections.

MAIN OUTCOME MEASURES AND RESULTS

Detection of spiral arteries (87%) and AA (35%) was highest in DB samples collected by vacuum suction compared to the two other methods. Pregnancies with AA detected in vacuum suctioned DB had lower gestational age at delivery, lower birth weight percentile and more often fetal growth restriction. Basal plate DB samples demonstrating AA associated with pregnancies affected by pathological fetal Dopplers, whereas AA detected in DP membrane rolls, did not.

CONCLUSIONS

Placental bed vacuum suction provides more spiral arteries and higher AA rate, suggesting underestimation of AA in conventional pathology samples of basal plate DB biopsies and DP. The association of AA with PE-related clinical parameters varies according to tissue collection method. Longitudinal studies could elucidate whether AA also identifies women with future premature cardiovascular risk.

Evaluation of placental vascularization in thrombophilia and intrauterine growth restriction (IUGR)

The placenta is an essential organ in the proper development of pregnancy, and it can present a lot of structural and vascular lesions that can affect fetal development. One of the pathologies associated with pregnancy, which can change the placental structure is thrombophilia (TPh), and this can be correlated with an intrauterine growth restriction (IUGR) of the fetus. Maternal clinical aspects (age, weight) can be correlated with fetal ones (weight, gender), but also with the structural and vascular aspect of the placenta. The placental structure associated with TPh and IUGR shows macroscopic changes, such as fibrin deposition, calcifications and placental infarctions, but microscopic lesions are best highlighted by classical staining techniques: Hematoxylin–Eosin (HE), Masson’s trichrome (MT) and Periodic Acid–Schiff (PAS)–Hematoxylin, but also by immunohistochemistry technique with the help of anti-cluster of differentiation 34 (CD34) antibody that could make it possible to quantify vascular density depending on the pathology. Microscopic changes were massive infarcts caused by vascular ischemia, intravenous and extravillous fibrin deposits, calcifications, and vascular thrombosis. All these clinical, morphological and morphopathological data are interconnected and may vary in the presence of TPh and IUGR.

When the Fetus Goes Still and the Birth Is Tragic: The Role of the Placenta in Stillbirths

Because of the critical role that placental structure and function plays during pregnancy, abnormal placental structure and function is closely related to stillbirth: when an infant dies before birth. However, understanding the role of the placental and specific lesions is incomplete, in part because of the variation in definitions of lesions and in classifying causes of stillbirths. Nevertheless, placental abnormalities are seen more frequently in stillbirths than live births, with placental abruption, chorioamnionitis, and maternal vascular malperfusion most commonly reported. Critically, some placental lesions affect the management of subsequent pregnancies. Histopathological examination of the placenta is recommended following stillbirth.

Recurrent intrauterine growth restriction: characteristic placental histopathological features and association with prenatal vascular Doppler

PURPOSE

Intrauterine growth restriction (IUGR) is a leading cause of perinatal morbidity and mortality, carrying a 20% recurrence rate. The placental disease is a cardinal factor among IUGR underlying processes. This study describes placental histopathological features (HPf) characteristic of recurrent IUGR (rIUGR) and assesses association with antenatal Doppler studies.

METHODS

We conducted a retrospective case-control study, between the years 2005-2016, evaluating 34 placentae of 17 women with rIUGR, and 59 placentae of a gestational age-matched control. Doppler studies within a week prior to delivery were analyzed for the rIUGR group.

RESULTS

Placental HPf characteristic of rIUGR is maternal and fetal vascular malperfusion lesions; maternal accelerated villous maturation and villous infarcts, repetitive feature rate 88.8% (95% CI 37.2-97), and fetal chorionic plate/stem villous thrombi, repetitive feature rate 66.6% (95% CI 30-90.3). Among women with abnormal Doppler, 83.3% had a placenta HPf of maternal vascular malperfusion lesions and 66.7% presented with a hypertensive disorder.

CONCLUSIONS

Women with rIUGR are a unique group of patients characterized by repetitive placental HPf of both maternal and fetal vascular malperfusion lesions. Specifically, maternal vascular malperfusion lesions are associated with abnormal Doppler findings. In conclusion, characteristic placental HPf may serve as predictors of future IUGR recurrence, thus offering early recognition of pregnancies that require "high-risk" antenatal care.

Automated segmentation of villi in histopathology images of placenta

PURPOSE

Manual analysis of clinical placenta pathology samples under the microscope is a costly and time-consuming task. Computer-aided diagnosis might offer a means to obtain fast and reliable results and also substantially reduce inter- and intra-rater variability. Here, we present a fully automated segmentation method that is capable of distinguishing the complex histological features of the human placenta (i.e., the chorionic villous structures).

METHODS

The proposed pipeline consists of multiple steps to segment individual placental villi structures in hematoxylin and eosin (H&E) stained placental images. Artifacts and undesired objects in the histological field of view are detected and excluded from further analysis. One of the challenges in our new algorithm is the detection and segmentation of touching villi in our dataset. The proposed algorithm uses the top-hat transformation to detect candidate concavities in each structure, which might represent two distinct villous structures in close proximity. The detected concavities are classified by extracting multiple features from each candidate concavity. Our proposed pipeline is evaluated against manual segmentations, confirmed by an expert pathologist, on 12 scans from three healthy control patients and nine patients diagnosed with preeclampsia, containing nearly 5000 individual villi. The results of our method are compared to a previously published method for villi segmentation.

RESULTS

Our algorithm detected placental villous structures with an F1 score of 80.76% and sensitivity of 82.18%. These values are substantially better than the previously published method, whose F1 score and sensitivity are 65.30% and 55.12%, respectively.

CONCLUSION

Our method is capable of distinguishing the complex histological features of the human placenta (i.e., the chorionic villous structures), removing artifacts over a large histopathology sample of human placenta, and (importantly) account for touching adjacent villi structures. Compared to existing methods, our developed method yielded high accuracy in detecting villi in placental images.

Re-view and view on maturation disorders in the placenta

Until delivery, the placenta plays an important mediator role between mother and fetus. This unit is affected by peristatic conditions, such as acute or chronic maternal diseases, malnutrition, drugs, and others. But also genetic factors and fetal malformations due to embryonic developmental disorders may contribute to macroscopically visible changes and functional disorders of the placenta. In a constantly ongoing progress of maturation, the placenta records and saves changes due to fetal distress partly as maturation disorders. Understanding of maturation disorders might, therefore, be an important contribution to a better understanding of influences on villous differentiation and might improve follow up and fetal outcome to reduce recurrence risk. However, an internationally unified classification system of maturation disorders does not exist. In this review, terminology, trials, and classifications of villous maturation disorders are summed up and compared, to pinpoint the need of agreement on an international unified and reproducible classification of maturation disorders.

The structure and utility of the placental pathology report

The placenta is one of the most exciting organs. It is dynamic; its morphology and function continuously develop and adjust over its brief life span. It mediates the physiology of two distinct yet highly interconnected individuals. The pathology that develops in the placenta, and the adaptations the placenta undergoes to mitigate this pathology, may influence the later life health of the mother and baby (Circ Res, 116, 2015, 715; Hum Reprod Update, 17, 2011, 397; Nutr Rev 71, 2013, S88; Placenta, 36, 2015, S20). Pathological placenta examination may reveal macroscopic and microscopic patterns that provide valuable information to the obstetricians, neonatologists, and pediatricians caring for the family. The placenta often plays a key role in understanding adverse fetal outcomes such as hypoxic brain injury, cerebral palsy, fetal growth restriction, stillbirth, and neonatal death (Placenta, 35, 2014, 552; Placenta, 52, 2017, 58; Placenta, 30, 2009, 700; Obstet Gynecol, 114, 2009, 809; Clin Perinatol, 33, 2006, 503; Pediatr Dev Pathol, 11, 2008, 456; Arch Pathol Lab Med, 124, 2000, 1785). Moreover, it may help to understand the pathophysiology of pregnancy, improve management of subsequent pregnancies, and assist in medicolegal assessment. Placental pathologic examination may even provide evidence of susceptibility to adult-onset diseases such as diabetes (Pediatr Dev Pathol, 6, 2003, 54; Diabetes Metab, 36, 2010, 682; BJOG, 113, 2006, 1126; Int J Gynaecol Obstet, 104, 2009, S25; Zentralbl Gynakol, 97, 1975, 875). Pathologic examination of the placenta may thus be of tremendous value, particularly for those women experiencing an adverse pregnancy outcome. However, this potential utility may be entirely wasted, if the findings are not communicated in an effective manner to the appropriate clinicians. An optimized, readily understandable report of pathological findings is essential for clinical utility.

Impact of fetal maceration grade on risk of maternal disseminated intravascular coagulation after intrauterine fetal death - A retrospective cohort study

Disseminated intravascular coagulation (DIC) is a life-threatening event that is the endpoint of a pathologically activated cascade leading to excessive consumption of platelets culminating in bleeding. Several diseases are known to be associated with DIC, some of which may also occur during pregnancy or the puerperium. One of the potential risk factors that have been considered as a potential trigger for DIC is the retention of a highly macerated fetus after intrauterine fetal death (IUFD). However, sparse evidence exists on its clinical implication on hemostasis parameters. In this retrospective single-center study, we investigated the role of fetal maceration grades 0-III on the risk of DIC in 91 women following IUFD between gestational weeks (+days) 22 + 0 and 41 + 6 between 2003 and 2017. We calculated the Erez DIC-score after consideration of maternal platelet count (PC), prothrombin time (PT) and fibrinogen (Fib) and correlated the findings with fetal maceration grade. Mean (±SD) age of women was 32.1 ± 6.7 years. Neither maternal hemostasis parameters (PC, PT, Fib), nor the Erez score showed a statistically significant difference between maceration grades 0-III with median values of 1 for all four grades (maceration grade I: range 0 to 27; I: 0 to 51; II: 0 to 52; III: 0 to 39). We therefore conclude, that the pathophysiology of DIC in women after singleton IUFD is unrelated to the degree of fetal maceration.

Histological Analysis of Term Placentas from Hyperimmune Globulin-Treated and Untreated Mothers with Primary Cytomegalovirus Infection

BACKGROUND

The Congenital Human Cytomegalovirus Infection Prevention (CHIP) study, a randomized, blinded, placebo-controlled trial, demonstrated that the efficacy of hyperimmune globulin (HIG) was not different from that of placebo regarding transmission of cytomegalovirus (CMV) from mothers to newborns. Our aim was to analyze histologically HIG effects on placentas collected for the CHIP study.

MATERIALS AND METHODS

Virological and histological analyses were performed on 40 placentas from transmitter and nontransmitter HIG-treated and untreated mothers by assessing the number of CMV-positive cells, tissue viral load, tissue damage, and compensatory mechanisms.

RESULTS

The HIG and placebo groups showed no significant differences in the number of CMV-positive cells (median number in 10 fields at 10 high-power fields: 2.5 vs. 2, p = 0.969) and viral load (median load: 5 copies/5 ng vs. 10.5 copies/5 ng, p = 0.874). Regarding histological examination, the scores of parameters related to tissue damage and hypoxic parenchymal compensation were higher in transmitters except for chorangiosis, with statistically significant differences observed for chronic villitis (p = 0.007), calcification (p = 0.011), and the total score of tissue damage (p < 0.001). The HIG and placebo groups showed no significant differences for all tissue damage and compensation parameters and overall scores.

DISCUSSION

HIGs are not able to reduce placental viral load and histological damage, which was significantly associated only with infection.

Association of severe placental inflammation with death prior to discharge and cerebral palsy in preterm infants

OBJECTIVE

The objective of our study was to identify placental patterns associated with death before discharge or cerebral palsy in a large cohort of preterm infants with a high follow-up rate at 2 years of corrected age.

DESIGN

Population-based monocentric study.

SETTINGS

Monocentric study in the maternity unit of the University Hospital of Angers, France between 24⁺⁰ and 33⁺⁶  weeks of gestation, between January 2008 and December 2011.

POPULATION

All singleton infants born alive with a placental examination were eligible.

METHODS

Clinical data (obstetric and neonatal) were collected prospectively through the LIFT cohort. Placental data were collected retrospectively from medical records. The main outcome measure was death before discharge or cerebral palsy.

RESULTS

We did not find any significant association between severe inflammatory lesions on the placenta and death [odds ratio (OR) 1.49; 95% CI 0.55-4.01; P = 0.43] or cerebral palsy (OR 1.41; 95% CI 0.43-4.62; P = 0.57). This lack of significant association persisted even after adjustment (aOR 0.9; 95% CI 0.20-2.30; P = 0.54; aOR 0.98; 95% CI 0.27-3.58; P = 0.97).

CONCLUSION

Our results do not provide evidence for a significant association between severe inflammatory placental lesions and either death before discharge or cerebral palsy at 2 years of corrected age in preterm infants born at <34 weeks of gestational age. Further studies remain necessary to confirm this result.

TWEETABLE ABSTRACT

We found no significant association between inflammatory placental lesions and death or cerebral palsy.

Quantitative assessment of placental morphology may identify specific causes of stillbirth

BACKGROUND

Stillbirth is frequently the result of pathological processes involving the placenta. Understanding the significance of specific lesions is hindered by qualitative subjective evaluation. We hypothesised that quantitative assessment of placental morphology would identify alterations between different causes of stillbirth and that placental phenotype would be independent of post-mortem effects and differ between live births and stillbirths with the same condition.

METHODS

Placental tissue was obtained from stillbirths with an established cause of death, those of unknown cause and live births. Image analysis was used to quantify different facets of placental structure including: syncytial nuclear aggregates (SNAs), proliferative cells, blood vessels, leukocytes and trophoblast area. These analyses were then applied to placental tissue from live births and stillbirths associated with fetal growth restriction (FGR), and to placental lobules before and after perfusion of the maternal side of the placental circulation to model post-mortem effects.

RESULTS

Different causes of stillbirth, particularly FGR, cord accident and hypertension had altered placental morphology compared to healthy live births. FGR stillbirths had increased SNAs and trophoblast area and reduced proliferation and villous vascularity; 2 out of 10 stillbirths of unknown cause had similar placental morphology to FGR. Stillbirths with FGR had reduced vascularity, proliferation and trophoblast area compared to FGR live births. Ex vivo perfusion did not reproduce the morphological findings of stillbirth.

CONCLUSION

These preliminary data suggest that addition of quantitative assessment of placental morphology may distinguish between different causes of stillbirth; these changes do not appear to be due to post-mortem effects. Applying quantitative assessment in addition to qualitative assessment might reduce the proportion of unexplained stillbirths.

Discriminative Learning for Automatic Staging of Placental Maturity via Multi-layer Fisher Vector

Currently, placental maturity is performed using subjective evaluation, which can be unreliable as it is highly dependent on the observations and experiences of clinicians. To address this problem, this paper proposes a method to automatically stage placenta maturity from B-mode ultrasound (US) images based on dense sampling and novel feature descriptors. Specifically, our proposed method first densely extracts features with a regular grid based on dense sampling instead of a few unreliable interest points. Followed by, these features are clustered using generative Gaussian mixture model (GMM) to obtain high order statistics of the features. The clustering representatives (i.e., cluster means) are encoded by Fisher vector (FV) for staging accuracy enhancement. Differing from the previous studies, a multi-layer FV is investigated to exploit the spatial information rather than the single layer FV. Experimental results show that the proposed method with the dense FV has achieved an area under the receiver of characteristics (AUC) of 96.77%, sensitivity and specificity of 98.04% and 93.75% for the placental maturity staging, respectively. Our experimental results also demonstrate that the dense feature outperforms the traditional sparse feature for placental maturity staging.

The association between ischemia modified albumin and placental histopathology in uncomplicated term deliveries

Ischemia modified albumin (IMA) is a marker of ischemia elevated in different clinical conditions and its use for hypoxia in perinatology is of current interest. We aimed to investigate the association between maternal and cord blood IMA levels and placental histopathological findings in uncomplicated term deliveries. In this study, placental histopathological evaluation in uncomplicated deliveries that ended with healthy newborns revealed 80.6% vasculopathy. The results support the hypothesis that hypoxia exceeding the placental reserve ends with fetal compromise. Moreover, the presence of maternal vasculopathy in placenta is not correlated with maternal and fetal IMA levels.

A systematic review of placental pathology in maternal diabetes mellitus

INTRODUCTION

During a pregnancy complicated by diabetes, the human placenta undergoes a number of functional and structural pathologic changes, such as increased placental weight and increased incidence of placental lesions including villous maturational defects and fibrinoid necrosis. The pathologic findings reported have differed among studies, potentially reflecting differences in type of diabetes, study methodology, or glycemic control of study participants. Alternatively, these discrepancies may represent different biologic adaptations to distinct metabolic diseases.

METHODS

We conducted a comprehensive review of English language citations in Pubmed and Embase using the keywords "diabetes", "placenta", AND "pathology". Abstracts were reviewed for relevance then full-text articles were reviewed in order to extract a comprehensive summary of current pathological findings associated with pregestational and gestational diabetes mellitus, as well as an understanding of the impact of glycemic control on placental pathology.

RESULTS

Placental abnormalities most consistently associated with maternal diabetes are an increased incidence of villous immaturity, increased measures of angiogenesis, and increased placental weight.

CONCLUSIONS

The literature suggests that, despite similarities in placental abnormalities, differences in placental pathology may reflect differences in pathophysiology among different types of diabetes. Consequently, standardization of terminology used to define placental lesions is warranted. Moreover, further research is needed to investigate the impact of pathophysiology, glycemic control and clinical factors, such as infant sex, weight and race, on placental structure and function.

Pathologic evaluation of normal and perfused term placental tissue

This study reports for the 1st time the incidence and interobserver variation of morphologic findings in a series of 34 term placentas from pregnancies with normal outcome used for perfusion studies. Histologic evaluation of placental tissue is challenging, especially when it comes to defining "normal tissue" versus "pathologic lesions." A scoring system for registration of abnormal morphologic findings was developed. Light microscopic examination was performed independently by 2 pathologists, and interobserver variation was analyzed. Findings in normal and perfused tissue were compared and selected findings were tested against success parameters from the perfusions. Finally, the criteria for frequent lesions with fair to poor interobserver variation in the nonperfused tissue were revised and reanalyzed. In the perfused tissue, the perfusion artefact "trophoblastic vacuolization," which is believed to represent dilated transtrophoblastic channels, was reproducible and significantly correlated to the perfusion marker "fetal leakage." In longer perfusions, microscopy of the perfused cotyledon revealed bacteria in the fetal vessels. This finding led to an adjustment in the perfusion protocol with addition of antibiotics to the medium. In the "normal" tissue, certain lesions were very frequent and showed only fair or poor interobserver agreement. Revised minimum criteria for these lesions were defined and found reproducible. This study has emphasized the value of pathologic examination as a supplement in placental perfusion models. Examination of the perfused cotyledon for trophoblastic vacuolization is recommended as an additional quality marker in perfusion models. The study also underlines the need for exact definitions of abnormality in frequent placental lesions.

Placental maturity, hypertensive disorders of pregnancy and birth weight

OBJECTIVES

To compare maturity of placentas from women with hypertensive disorders with those from normotensive pregnancies and to determine the relationship between placental maturity (PM) and the diagnosis of small-for-gestational-age (SGA) in the newborns.

MATERIALS AND METHODS

We examined placental stained specimens from women with normotensive pregnancies (n = 100), diagnosis of gestational hypertension (n = 38), mild (n = 10), or severe preeclampsia (n = 34) in an optical microscope. Placental Maturity Index (PMI) was calculated as the number of vasculo-syncytial membranes (VSM) in 1 mm(2) divided by VSM thickness (µm). Hypermaturity was defined as >90th percentile of the PMI from placentas of normotensive pregnancies. Newborns were classified as SGA, adequate-for-gestational-age (AGA) or large-for-gestational-age (<10th, 10-90th, and >90th percentile from weight for gestational age reference tables, respectively).

RESULTS

PMI in preeclamptic women (taking together mild and severe preeclampsia, PMI = 43.4 ± 1.6) was significantly higher than in normotensive women (PMI = 36 ± 2, p = 0.045). Hypermaturity was more frequent (p < 0.05) in placentas from women with preeclampsia than in those from normotensive women only in preterm pregnancies (<37 weeks), but not in those at term (p = 0.41). The frequency of hypermaturity in placentas from women with gestational hypertension was not statistically different than in normotensive women. Hypermaturity was also more frequent in placentas from SGA (OR = 2.63, p < 0.05) than in AGA newborns.

CONCLUSION

The PMI was increased in preeclampsia, but not in gestational hypertension. Placental hypermaturity was also associated with the diagnosis of SGA in newborns. PM might have a role in the relationship between maternal factors and SGA.

Wavelet principal component analysis of fetal movement counting data preceding hospital examinations due to decreased fetal movement: a prospective cohort study

Background

Fetal movement (FM) counting is a simple and widely used method of assessing fetal well-being. However, little is known about what women perceive as decreased fetal movement (DFM) and how maternally perceived DFM is reflected in FM charts.

Methods

We analyzed FM counting data from 148 DFM events occurring in 137 pregnancies. The women counted FM daily from pregnancy week 24 until birth using a modified count-to-ten procedure. Common temporal patterns for the two weeks preceding hospital examination due to DFM were extracted from the FM charts using wavelet principal component analysis; a statistical methodology particularly developed for modeling temporal data with sudden changes, i.e. spikes that are frequently found in FM data. The association of the extracted temporal patterns with fetal complications was assessed by including the individuals’ scores on the wavelet principal components as explanatory variables in multivariable logistic regression analyses for two outcome measures: (i) complications identified during DFM-related consultations (n = 148) and (ii) fetal compromise at the time of consultation (including relevant information about birth outcome and placental pathology). The latter outcome variable was restricted to the DFM events occurring within 21 days before birth (n = 76).

Results

Analyzing the 148 and 76 DFM events, the first three main temporal FM counting patterns explained 87.2% and 87.4%, respectively, of all temporal variation in the FM charts. These three temporal patterns represented overall counting times, sudden spikes around the time of DFM events, and an inverted U-shaped pattern, explaining 75.3%, 8.6%, and 3.3% and 72.5%, 9.6%, and 5.3% of variation in the total cohort and subsample, respectively. Neither of the temporal patterns was significantly associated with the two outcome measures.

Conclusions

Acknowledging that sudden, large changes in fetal activity may be underreported in FM charts, our study showed that the temporal FM counting patterns in the two weeks preceding DFM-related consultation contributed little to identify clinically important changes in perceived FM. It thus provides insufficient information for giving detailed advice to women on when to contact health care providers. The importance of qualitative features of maternally perceived DFM should be further explored.