Distal villous hypoplasia

Placenta and Intestinal Injury in Preterm Infants

Necrotizing enterocolitis (NEC) is one of the most common gastrointestinal conditions affecting 6 to 10% of low-birth-weight infants and remains a leading cause of death. The risk factors associated with NEC are complex and multifactorial, including preterm birth and intrauterine exposure to inflammation and hypoxia. Chorioamnionitis has been associated with intestinal injury in animal and human clinical studies. This review presents current evidence about the clinical impact of the intrauterine environment on intestinal injury during pregnancy and postpregnancy. We present information from our own clinical and laboratory research in conjunction with information collected from an extensive search in the databases PubMed, EMBASE, and Scopus. Prospective multicenter studies, including accurate and precise clinical, maternal, and laboratory predictors (e.g., inflammatory biomarkers), will help identify the mechanisms associated with the placental pathology, the development of NEC, and the impact of in utero-triggered inflammation on the clinical outcomes. Filling the knowledge gap to link the inflammatory surge to postnatal life will aid in identifying at-risk infants for NEC in a timely manner and facilitate the development of novel immunomodulatory treatments or interventions to improve the outcomes of these vulnerable infants. KEY POINTS: · Placental inflammatory and vascular lesions are associated with NEC severity.. · Higher grade chorioamnionitis with a fetal response is associated with an increased risk of surgical NEC.. · There is a need for routine bedside utilization of placenta pathology in clinical decision-making..

Cytology Techniques Can Provide Insight into Human Placental Structure Including Syncytiotrophoblast Nuclear Spatial Organisation

The aim of this study was to provide the first systematic description of human placental cytology appearances and to investigate syncytiotrophoblast nuclear organisation patterns using cytology techniques. Term placentas from normal pregnancies were sampled using fine-needle aspiration (FNA) and direct scrapes. Standard histological examination was also performed to exclude pathological changes in the placentas being studied. Both Papanicolaou-stained cytospin preparations and air-dried Giemsa slides from FNA provided high-quality material for cytological assessment with good cellularity. Among the key features of the cytology preparations were villous "microbiopsies" that allowed for the three-dimensional appreciation of villous branching patterns. Cytological appearances, including nuclear characteristics of villous cytotrophoblast and syncytiotrophoblast, were also well demonstrated. In microbiopsies and detached villous trophoblast sheets, complex patterns of syncytiotrophoblast nuclear organisation, not previously described cytologically, were observed, including irregular spacing of nuclei, syncytioplasm windows and linear nuclear arrangements. This study showed that placental cytology (a) provides technically excellent material for cytological evaluation, (b) confirms the presence of complex nuclear organisational patterns in the syncytiotrophoblast by eliminating the possibility of tangential sectioning artefact, (c) provides superior nuclear detail over standard histological sections and (d) may be an untapped research resource for the investigation of normal and pathological processes because of its ability to look at the placenta in a novel way and through its potential for both ex vivo and in vivo placental sampling.

Intrauterine Growth Restriction Due to Gestational Diabetes: From Pathophysiology to Diagnosis and Management

Intrauterine growth restriction (IUGR) represents a condition where the fetal weight is less than the 10th percentile for gestational age, or the estimated fetal weight is lower than expected based on gestational age. IUGR can be caused by various factors such as maternal, placental or fetal factors and can lead to various complications for both the fetus and the mother, including fetal distress, stillbirth, preterm delivery, and maternal hypertension. Women with gestational diabetes are at an increased risk of developing IUGR. This article reviews the different aspects of gestational diabetes in addition to IUGR, the diagnostic methods available for IUGR detection, including ultrasound and Doppler studies, discusses the management strategies for women with IUGR and gestational diabetes and analyzes the importance of early detection and timely intervention to improve pregnancy outcomes.

Association of Placental Pathologic Findings with the Severity of Necrotizing Enterocolitis in Preterm infants - A Matched Case-Control Study

OBJECTIVE

To determine the association of placental pathology with the severity of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

This single-center matched case-control study included infants with NEC (n = 107) and gestational age and birth weight-matched controls (n = 130), born between 2013 and 2020. Placentas were evaluated according to the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

Acute histologic chorioamnionitis with the fetal response was significantly more common in infants with surgical NEC vs. medical NEC (35.4% vs. 15.3%; p = 0.02). On regression model, infants with multiple placental pathologies (OR 2.16; 95% CI 1.01 - 4.73; p = 0.04) and maternal vascular malperfusion (OR 2.2; 95% CI 1.12 - 4.51; p = 0.02) had higher odds of either medical or surgical NEC than controls.

CONCLUSION

Infants with multiple placental lesions, including placental inflammatory and vascular lesions, were at higher risk of medical or surgical NEC in the postnatal period.

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.

Correlation of placental pathology with the postoperative outcomes and white matter injury in preterm infants following necrotizing enterocolitis

BACKGROUND

To determine the association of placental pathologic lesions with postoperative outcomes, survival, and white matter injury (WMI) in preterm infants with NEC.

METHODS

A retrospective chart review of 107 neonates with NEC (Bell stage > IIa) from Jan 2013- June 2020 was completed. Demographic, clinical, and outcome data were compared between infants with or without placental pathologic lesions.

RESULTS

In this cohort, 59/107 (55%) infants had medical NEC, and 48 (45%) had surgical NEC. The infants had a mean gestational age of 28.1±3.7 weeks and a birth weight of 1103±647 g. Maternal vascular malperfusion (82/107, 76.6%) and acute histological chorioamnionitis (42, 39.3%) were the most common pathological placental lesions. Acute histologic chorioamnionitis with fetal inflammatory response was more common in infants with surgical NEC vs. medical NEC (35.4% vs. 15.3%; p = 0.02). The NEC Infants with WMI on brain MRI scans had a significantly higher incidence of acute histological chorioamnionitis (52% vs. 27.8%; P = 0.04). No significant differences in mortality, length of stay and postoperative outcomes in neonates with and without acute histologic chorioamnionitis with fetal inflammatory response were noted. On unadjusted logistic regression, acute histologic chorioamnionitis without fetal inflammatory response was also associated with higher odds of WMI (OR 2.81; 95% CI 1.05-7.54; p = 0.039).

CONCLUSION

Acute histological chorioamnionitis without fetal inflammatory response was associated with higher odds of WMI in infants with NEC, with no significant impact on mortality and other postoperative outcomes.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

Syncytiotrophoblast stress in preeclampsia: the convergence point for multiple pathways

Preeclampsia evolves in 2 stages: a placental problem that generates signals to the mother to cause a range of responses that comprise the second stage (preeclampsia syndrome). The first stage of early-onset preeclampsia is poor placentation, which we here call malplacentation. The spiral arteries are incompletely remodeled, leading to later placental malperfusion, relatively early in the second half of pregnancy. The long duration of the first stage (several months) is unsurprisingly associated with fetal growth restriction. The first stage of late-onset preeclampsia, approximately 80% of total cases, is shorter (several weeks) and part of a process that is common to all pregnancies. Placental function declines as it outgrows uterine capacity, with increasing chorionic villous packing, compression of the intervillous space, and fetal hypoxia, and causes late-onset clinical presentations such as "unexplained" stillbirths, late-onset fetal growth restriction, or preeclampsia. The second stages of early- and late-onset preeclampsia share syncytiotrophoblast stress as the most relevant feature that causes the maternal syndrome. Syncytiotrophoblast stress signals in the maternal circulation are probably the most specific biomarkers for preeclampsia. In addition, soluble fms-like tyrosine kinase-1 (mainly produced by syncytiotrophoblast) is the best-known biomarker and is routinely used in clinical practice in many locations. How the stress signals change over time in normal pregnancies indicates that syncytiotrophoblast stress begins on average at 30 to 32 weeks' gestation and progresses to term. At term, syncytiotrophoblast shows increasing markers of stress, including apoptosis, pyroptosis, autophagy, syncytial knots, and necrosis. We label this phenotype the "twilight placenta" and argue that it accounts for the clinical problems of postmature pregnancies. Senescence as a stress response differs in multinuclear syncytiotrophoblast from that of mononuclear cells. Syncytiotrophoblast irreversibly acquires part of the senescence phenotype (cell cycle arrest) when it is formed by cell fusion. The 2 pathways converge on the common pathologic endpoint, syncytiotrophoblast stress, and contribute to preeclampsia subtypes. We highlight that the well-known heterogeneity of the preeclampsia syndrome arises from different pathways to this common endpoint, influenced by maternal genetics, epigenetics, lifestyle, and environmental factors with different fetal and maternal responses to the ensuing insults. This complexity mandates a reassessment of our approach to predicting and preventing preeclampsia, and we summarize research priorities to maximize what we can learn about these important issues.

Fetal Growth Restriction in Hypertensive vs. Heavy Smoking Women-Placental Pathology, Ultrasound Findings, and Pregnancy Outcomes

We compared placental pathology, ultrasonographic findings, and obstetric outcomes, in gestations complicated by fetal growth restriction (FGR) with either a background of hypertensive disorder or heavy tobacco cigarette smoking. The medical records and placental pathology reports of pregnancies complicated with FGR (birthweight < 10th percentile) between December 2008 and May 2018 from a single tertiary center were reviewed. Placental pathology, ultrasound findings, and pregnancy outcomes were compared between hypertensive patients (HTN) and heavy smokers (SMO). We included 213 pregnancies: 129 (60.6%) in the SMO group and 84 (39.4%) in the HTN group. The HTN group was characterized by a higher BMI (p = 0.01), higher rates of Cesarean deliveries (p = 0.006), and a lower gestational age at delivery (35.6 ± 3.8 vs. 37.5 ± 2.9 weeks, p < 0.001). The HTN group had higher rates of placental weights < 10th percentile (p = 0.04) and maternal vascular malperfusion lesions (p < 0.001), while the SMO group had higher rates of inflammatory lesions (p = 0.04). On ultrasound, the HTN group had a higher head/abdomen circumference ratio (p < 0.001) and more abnormal Doppler studies (< 0.001). Neonates in the HTN group had lower birthweights (p < 0.001) and higher rates of NICU admissions (p = 0.002) and adverse neonatal outcome (p = 0.006). On multivariable analysis, gestational age at delivery (aOR = 0.65, 95%CI 0.55-0.87), hypertensive disorders (aOR = 1.8, 95%CI = 1.21-4.81), placental MVM lesions (aOR = 1.23, 95%CI = 1.08-5.02), and the combination of HTN+MVM (aOR = 2.63, 95%CI 1.78-7.30) were independently associated with adverse neonatal outcome. Hypertension and smoking may lead to FGR in different pathways as the two groups significantly differed in maternal characteristics, placental pathology, ultrasound findings, and neonatal outcomes. A hypertensive disorder probably represents a more hostile maternal environment than smoking and these pregnancies would probably benefit from closes monitoring.

Region-specific changes in the mRNA and protein expression of LCPUFA biosynthesis enzymes and transporters in the placentae of women with preeclampsia

The biosynthesis and transport of long chain polyunsaturated fatty acids (LCPUFA) require the activity of fatty acid desaturase (FADS) enzymes, fatty acid transport proteins (FATP) and fatty acid binding proteins (FABP). In a previous study we have demonstrated region-specific changes in the LCPUFA levels in preeclampsia (PE) as compared to the normotensive control (NC) placentae.

AIM

To understand the region-specific changes in the mRNA levels and protein expression of biosynthesis enzymes and transporters of LCPUFA in PE and NC placentae.

METHODS

In this cross-sectional study, 20 NC women and 44 women with PE (23 term (TPE) and 21 preterm PE (PTPE)) were recruited. The samples were collected from four regions of the placentae considering cord insertion as the center (CM, central maternal/basal; CF, central fetal/chorionic; PM, peripheral maternal/basal and PF, peripheral fetal/chorionic). The mRNA levels were estimated using qRT-PCR. Statistical analysis was done using both post hoc least significant difference (LSD) test and Benjamini Hochberg correction in the analysis of covariance. Preliminarily, localization and expression of proteins were studied by immunohistochemistry (n = 3/group).

RESULTS

The mRNA levels of FADS1, FADS2 and FATP1 were lower in the central regions (CM and CF) of the PE placentae (both TPE and PTPE) as compared to NC. These differences in the mRNA levels were observed by the LSD test and were not significant after the Benjamini Hochberg correction. Preliminary findings of IHC indicate that the protein expression of FADS1 and FATP4 was higher in the basal regions (CM and PM) of the PE placentae as compared to NC. FADS1, FADS2 and FATP4 proteins were localized in the syncytiotrophoblasts, cytotrophoblasts, mesenchymal cells, endothelial cells of the fetal capillaries and extravillous trophoblasts of the placenta.

CONCLUSION

FADS enzymes are detected in the placentae of Indian women. In PE placentae, there are region-specific alterations in the mRNA and protein levels of LCPUFA biosynthesis enzymes (FADS1 and FADS2) and transporters (FATP1, FATP4 and FABP3) as compared to term NC. These changes were more pronounced toward the basal side and region around the cord insertion.

Placental Findings in Singleton Stillbirths: A Case-control Study

AIMS

This prospective observational study compared placental lesions of stillbirth cases and live birth controls, and aimed to determine the cause of stillbirth.

METHODS

The study enrolled 85 stillbirths and 85 live births at the time of delivery.

RESULTS

There was significantly increased incidence of placental abruption (p = 0.005) and gestational diabetes (p = 0.032) in mothers with stillbirths. Histopathological examination of placenta was significantly abnormal in stillbirths compared with live births (p = 0.004). Delayed villous maturation was significantly more in stillbirths (38.82 vs. 16.47%; p = 0.002). Acute (30.59 vs. 16.47%; p = 0.04) and chronic diffuse villitis (16.47 vs. 4.7%; p = 0.02), chorionic plate acute vasculitis (28.235 vs. 14.11%; p = 0.04) were significantly more in stillbirths. Foetal vascular thrombi in the chorionic plate (30.58 vs. 14.12%; p = 0.02) and avascular villi (24.7 vs. 8.23%; p = 0.006) were significantly more in stillbirths.

CONCLUSION

These abnormal placental patterns could provide information about the etiopathogenisis in stillbirths of unknown aetiology.

The clinical heterogeneity of preeclampsia is related to both placental gene expression and placental histopathology

BACKGROUND

Preeclampsia is a life-threatening disorder of pregnancy, demonstrating a high degree of heterogeneity in clinical features such as presentation, disease severity, and outcomes. This heterogeneity suggests distinct pathophysiological mechanisms may be driving the placental disease underlying this disorder. Our group recently reported distinct clusters of placental gene expression in preeclampsia and control pregnancies, allowing for the identification of at least 3 clinically relevant gene expression-based subtypes of preeclampsia. Histopathological examination of a small number of samples from 2 of the gene expression-based subtypes revealed placental lesions consistent with their gene expression phenotype, suggesting that detailed placental histopathology may provide further insight into the pathophysiology underlying these distinct gene expression-based subtypes.

OBJECTIVES

The objective of the study was to assess histopathological lesions in the placentas of patients belonging to each identified gene expression-based subtype of preeclampsia, characterized in our previous study. Our goal was to further understand the pathophysiologies defining these gene expression-based subtypes by integrating gene expression with histopathological findings, possibly identifying additional subgroups of preeclampsia patients.

STUDY DESIGN

Paraffin-embedded placental biopsies from patients included in the gene expression profiling study (n = 142 of 157, 90.4%) were sectioned, hematoxylin and eosin stained, and imaged. An experienced perinatal pathologist, blinded to gene expression findings and clinical information, assessed the presence and severity of histological lesions using a comprehensive, standardized data collection form. The frequency and severity scores of observed histopathological lesions were compared among gene expression-based subtypes as well as within each subtype using using Fisher exact tests, Kruskal-Wallis tests, and hierarchical clustering. The histological findings of the placental samples were visualized using t-distributed stochastic neighbor embedding and phylogenetic trees. Concordance and discordance between gene expression findings and histopathology were also investigated and visualized using principal component analysis.

RESULTS

Several histological lesions were found to be characteristic of each gene expression-based preeclampsia subtype. The overall concordance between gene expression and histopathology for all samples was 65% (93 of 142), with characteristic placental lesions for each gene expression-based subtype complementing prior gene enrichment findings (ie, placentas with enrichment of hypoxia-associated genes showed severe lesions of maternal vascular malperfusion). Concordant samples were located in the central area of each gene expression-based cluster when viewed on a principal component analysis plot. Interestingly, discordant samples (gene expression and histopathology not reflective of one another) were generally found to lie at the periphery of the gene expression-based clusters and tended to border the group of patients with phenotypically similar histopathology.

CONCLUSION

Our findings demonstrates a high degree of concordance between placental lesions and gene expression across subtypes of preeclampsia. Additionally, novel integrative analysis of scored placental histopathology severity and gene expression findings allowed for the identification of patients with intermediate phenotypes of preeclampsia not apparent through gene expression profiling alone. Future investigations should examine the temporal relationship between these 2 modalities as well as consider the maternal and fetal contributions to these subtypes of disease.

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.

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.

Diagnosis and Management of IUGR in Pregnancy Complicated by Type 1 Diabetes Mellitus

This review discusses available literature on the diagnosis and management of intrauterine growth restriction (IUGR) in women with type 1 diabetes. IUGR is diagnosed when ultrasound-estimated fetal weight is below the 10th percentile for gestational age. IUGR diagnosis implies a pathologic process behind low fetal weight. IUGR in pregnancy complicated by type 1 diabetes is usually caused by placental dysfunction related to maternal vasculopathy. Prevention of IUGR should ideally start before pregnancy. Strict glycemic control and intensive treatment of nephropathy and hypertension are essential. Low-dose aspirin initiated before 16 gestational weeks can also reduce IUGR risk in women with vasculopathy. Umbilical and uterine artery Doppler studies can guide diagnosis and surveillance of fetuses with IUGR. Decisions regarding the timing of delivery should be based on assessment of umbilical artery Doppler. The risk of prematurity and impaired fetal lung maturation should always be considered, especially in fetuses younger than 32 weeks.

Clustering and classical analysis of clinical and placental phenotypes in fetal growth restriction and constitutional fetal smallness

This study aims to determine whether placental examination can be used to distinguish between pathologic fetal growth restriction (FGR) and constitutional fetal smallness. Data were extracted from a clinicoplacental database of high risk pregnancies during the period 1994-2013. These data were used to compare the 590 consecutive cases having birth weights below the 10th percentile with the 5201 remaining cases having gestational ages ≥20 weeks. The authors analyzed 20 clinical and 46 placental phenotypes using classical statistics, clustering analysis, and multidimensional scaling. Of the low-birth-weight babies, the following types of cases were compared: Four categories of placental phenotypes (those with features of poor uteroplacental perfusion, postuterine placental pathology, chronic inflammation, and a mixed category) better defined the presumably true FGR than did the clinical phenotypes. Maternal smoking and oligohydramnios were associated with fewer abnormal placental phenotypes than were maternal hypertensive diseases and abnormal Dopplers. Early-onset cases of fetal smallness clustered with placental features of poor uteroplacental perfusion, whereas late onset cases did not. Placental examination helps to retrospectively distinguish constitutionally small fetuses from those that are pathologically growth restricted. The latter correlate best with the clinical risk for FGR and with early-onset FGR. This correlation may have prognostic significance for the child and for future pregnancies, since hypoxic placental lesions can occur without clinical risk factors but with a tendency to recur in future pregnancies.

The Placental Distal Villous Hypoplasia Pattern: Interobserver Agreement and Automated Fractal Dimension as an Objective Metric

The distal villous hypoplasia (DVH) pattern is a placental correlate of fetal growth restriction. Because the pattern seems to involve less complexity than do appropriately developed placental villi, we postulated that it may be associated with lower fractal dimension-a mathematical measure of complexity. Our study objectives were to evaluate interobserver agreement related to the DVH pattern among expert pathologists and to determine whether pathologist classification of DVH correlates with fractal dimension. A study set of 30 images of placental parenchyma at ×4 magnification was created by a single pathologist from a digital slide archive. The images were graded for the DVH pattern according to pre-specified definitions and included 10 images graded as "no DVH" (grade  =  0), 10 with mild to moderate DVH (grade  =  1), and 10 with severe DVH (grade  =  2). The images were randomly sorted and shown to a panel of 4 international experts who similarly graded the images for DVH. Weighted kappas were calculated. For each image, fractal dimension was calculated by the Box Counting method. The correlation coefficient between (1) the averaged DVH scores obtained by the 5 pathologists and (2) fractal dimension was calculated. The mean weighted kappa score among the observers was 0.59 (range: 0.42-0.70). The correlation coefficient between fractal dimension and the averaged DVH score was -0.915 (P < 0.001). Expert pathologists achieve fair to substantial agreement in grading DVH, indicating consensus on the definition of DVH. Distal villous hypoplasia correlates extremely well with fractal dimension and represents an objective measure for DVH.

Placental pathology in early intrauterine growth restriction associated with maternal hypertension

INTRODUCTION

To identify key pathological characteristics of placentas from pregnancies complicated by early intrauterine growth restriction, and to examine their relations with maternal hypertensive disease and umbilical artery Doppler waveform abnormalities.

METHODS

Single-center retrospective cohort study of singleton pregnancies with abnormal umbilical artery Doppler flow patterns resulting in a live birth <34 weeks of a baby with a weight <10th percentile for gestational age. Umbilical artery end diastolic flow was classified as being either present or absent/reversed (AREDF). Data were stratified into intrauterine growth restriction with or without hypertensive disease and pathological characteristics were compared between these various conditions according to predefined scoring criteria.

RESULTS

Among 164 placentas studied, we found high rates of characteristic histopathological features that were associated with intrauterine growth restriction, including infarction (>5% in 42%), chronic villitis (21%), chronic chorioamnionitis (36%), membrane necrosis (20%), elevated nucleated red blood cells (89%), increased syncytial knotting (93%), increased villous maturation (98%), fetal thrombosis (32%) and distal villous hypoplasia (35%). Chronic inflammation of fetal membranes and syncytial knotting were more common in women with concomitant hypertensive disease as compared to women with normotensive IUGR (p < 0.05). Placentas from women with umbilical artery AREDF were more likely to show increased numbers of nucleated red blood cells and distal villous hypoplasia (p < 0.05).

DISCUSSION

Placentas of women with early IUGR show high rates of several histological aberrations. Further, concomitant maternal hypertension is associated with characteristic inflammatory changes and umbilical artery AREDF with signs of chronic hypoxia.

Placental hyperinflation and the risk of adverse perinatal outcome

OBJECTIVES

To determine the pathological basis and clinical associations of excessively thick placentae observed at second-trimester ultrasound examination.

METHODS

In a retrospective cohort of 19 singleton high-risk second-trimester pregnancies noted to have a placental length-to-maximum thickness ratio ≤ 2.0, maximum sonographic placental thickness was correlated with clinical outcome, maximum placental thickness after delivery and placental pathological findings. Results were compared with those of an intermediate group of 21 high-risk pregnancies with normal placental dimensions and a control group of 18 low-risk pregnancies also with normal placental dimensions. Increased maximum placental thickness (> 28 mm) and abnormal placental deflation following delivery (pathology - sonography difference in maximum placental thickness < -2 mm) were defined by the upper and lower quartile values, respectively, in the control group.

RESULTS

The study group exhibited significantly more adverse outcomes and gross pathological placental features compared with both intermediate and control groups. Despite increased sonographic maximum placental thickness in the study group (median, 55 (range, 40-75) mm compared with both the intermediate group (median, 27 (range, 22-41) mm, P < 0.0001) and the control group (median 26 (range, 23-36) mm, P < 0.0001)), all three groups had similar maximal placental thickness following delivery (study group: median, 24 (range, 10-50) mm vs intermediate group: median, 27 (range, 15-40) mm, P = 0.82 and vs control group: median, 28.5 (range, 18-44), P = 0.42). Pathology-sonography difference in maximum placental thickness in the study group (median, -30 (range, -42 to 0) mm) was significantly greater than that in either the intermediate (median, -2 (range, -11 to 9) mm, P < 0.0001) or the control (median, 1.5 (range, -10 to 18) mm, P < 0.0001) group and was significantly associated with abnormal development of the gas-exchanging placental villi (distal villous hypoplasia) (P = 0.0001).

CONCLUSIONS

Increased second-trimester sonographic maximum placental thickness represents a pathological finding associated with severe adverse perinatal outcome. This observation is due to overinflation of the intervillous space by maternal blood rather than to adaptive formation of functional placental tissue.