Livebirths with placental hemorrhagic endovasculitis: interlesional relationships and perinatal outcomes

Maternal Factors and Placental Pathologies Associated with a Diagnosis of Chronic Villitis

OBJECTIVE

 To evaluate maternal risk factors associated with chronic villitis of unknown etiology (VUE) and to describe cooccurring placental pathologies.

STUDY DESIGN

 A retrospective case-control study was conducted using placental pathology records from deliveries ≥ 20 weeks between 2010 and 2018. Cases were placentas with documented chronic villitis without infectious cause, hereafter called VUE. Controls were placentas without this diagnosis, matched to the cases 2:1. Maternal and neonatal demographic and clinical data were collected. Descriptive statistics are reported with Fisher's exact test or a chi-squared test, as appropriate, and multivariable conditional logistic regression was conducted.

RESULTS

 Our study included 352 cases with VUE and 657 controls. A diagnosis of gestational diabetes (p = 0.03) and gestational hypertension (p = 0.06) was 1.5 times more likely to occur in those with a VUE diagnosis. A trend was also seen for chronic hypertension (odds ratio [OR] = 1.7, p = 0.07) and preeclampsia (OR = 1.5, p = 0.09) compared with controls. Placentas with VUE, specifically high-grade VUE, were more likely to be small for gestational age (p = 0.01), and to be diagnosed with other placental findings including lymphoplasmacytic or chronic deciduitis (p < 0.01), maternal (p < 0.01) and fetal vascular malperfusion (p = 0.02), and chorionitis (acute or chronic; p < 0.01).

CONCLUSION

 Gestational diabetes and hypertension were associated with a diagnosis of VUE, and overall, VUE placentas have more abnormal placental findings compared with control. Understanding VUE risk factors may facilitate prenatal care strategies and counseling to achieve the best outcomes for pregnant patients and their neonates.

KEY POINTS

· VUE is a common inflammatory lesion of the placenta.. · Gestational diabetes and hypertension are associated with a VUE diagnosis.. · Findings of other placental pathologies increase in VUE..

Association between fetal vascular malperfusion and gestational diabetes

AIM

Diabetes mellitus (DM) is a major complication in pregnancy. Placental lesions with DM remain unclear and controversial. Recently, the terms of placental pathological findings, such as maternal and fetal vascular malperfusions (MVM and FVM, respectively) were introduced by the Amsterdam Placental Workshop Group Consensus Statement (APWGCS). FVM cases were classified as the partial obstruction type (global FVM) and the complete obstruction type (segmental FVM). The aim of this study was to clarify the pathological characteristics of the placenta with pregestational DM/gestational DM; GDM according to APWGCS.

METHODS

We studied the placentas of 182 DM women (27 pregestational DM and 155 GDM) and control placentas of 460 women without DM during 2011-2018. We excluded cases of intrauterine fetal death or multiple pregnancies. We reviewed microscopical findings including, MVM, FVM, chorioamnionitis with the slides according to the APWGCS.

RESULTS

Microscopically, the incidence of FVM was significantly higher in GDM patients than control (17% vs. 10%, p = 0.0138), but not significant in pregestational DM (11%, p = 0.7410). Segmental FVM (complete obstruction) was significantly more observed in GDM than control group (5% vs. 0.4%, p = 0.0013). Segmental FVM in GDM showed high incidence of light-for-dates infant (three of seven cases, 43%, p = 0.0288). In addition, several segmental FVM findings (villous stromal-vascular karyorrhexis and stem vessel occlusion) were frequently noted in 2 or 3 points positive of 75 g oral glucose tolerance test than 1 point positive GDM.

CONCLUSION

Our placental findings suggest disorder of carbohydrate metabolism might affect the fetal vascular damage, especially complete fetal vascular obstruction.

Placental surface shape, function, and effects of maternal and fetal vascular pathology

GOAL

In clinical practice, variability of placental surface shape is common. We measure the average placental shape in a birth cohort and the effect deviations from the average have on placental functional efficiency. We test whether altered placental shape improves the specificity of histopathology diagnoses of maternal uteroplacental and fetoplacental vascular pathology for clinical outcomes.

MATERIALS AND METHODS

1225 Placentas from a prospective cohort had chorionic plate digital photographs with perimeters marked at 1-2 cm intervals. After exclusions of pre-term (n = 202) and velamentous cord insertion (n = 44), 979 (95.7%) placentas were analyzed. Median shape and mean perimeter were estimated. The relationship of fetal and placental weight was used as an index of placental efficiency termed "β". The principal placental histopathology diagnoses of maternal uteroplacental and fetoplacental vascular pathologies were coded by review of individual lesion scores. Acute fetal inflammation was scored as a "negative control" pathology not expected to affect shape. ANOVA with Bonferroni tests for subgroup comparisons were used.

RESULTS

The mean placental chorionic shape at term was round with a radius estimated at 9.1 cm. Increased variability of the placental shape was associated with lower placental functional efficiency. After stratifying on placental shape, the presence of either maternal uteroplacental or fetoplacental vascular pathology was significantly associated with lower placental efficiency only when shape was abnormal.

CONCLUSIONS

Quantifying abnormality of placental shape is a meaningful clinical tool. Abnormal shapes are associated with reduced placental efficiency. We hypothesize that such shapes reflect deformations of placental vascular architecture, and that an abnormal placental shape serves as a marker of maternal uteroplacental and/or fetoplacental vascular pathology of sufficiently long standing to impact placental (and by extension, potentially fetal) development.

Placental vascular obstructive lesions: risk factor for developing necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe neonatal disease affecting particularly preterm infants. Its exact pathogenesis still remains unknown. In this study, we have compared the prevalence of vascular obstructive lesions in placentae of premature newborns which developed NEC and of a control group. We further compared separately the findings of placentae of infants of less than 30 weeks of gestation, the age group in which NEC occurs most frequently. We found signs of fetal vascular obstructive lesions in 65% of the placentae of preterm patients developing NEC, compared to only 17% of the placentae of preterm patients in the control group. In the age groups below 30 weeks of gestation, 58.5% of placentae of later NEC patients presented such lesions compared to 24.5% in the control group. The significant difference between NEC and control group suggests a strong association between fetal vascular obstructive lesions and NEC. Therefore, we propose that fetal vascular obstructive lesions might be considered as a risk factor for the development of NEC in premature infants.

Placental vascular pathology findings and pathways to preterm delivery

The authors examined the associations between placental vascular findings and preterm delivery in 1,053 subcohort women (239 preterm, 814 term) from a Michigan pregnancy cohort study (1998-2004). Twenty-nine placental vascular variables from microscopic examinations were grouped into 5 constructs: 3 maternal constructs-obstructive lesions (MV-O), bleeding/vessel integrity (MV-I), and lack of physiologic conversion of maternal spiral arteries (MV-D)--and 2 fetal constructs--obstructive lesions (FV-O) and bleeding/vessel integrity (FV-I). Construct-specific scores were created by adding the number of positive findings and deriving a dichotomous variable to approximate the top quintile ("high") and bottom 4 quintiles ("not high") within each construct. In multivariate polytomous logistic regression models, medically indicated preterm delivery at <35 weeks was significantly associated with high scores for each of the vascular constructs; adjusted odds ratios ranged from 2.4 to 5.4. Spontaneous preterm delivery at 35-36 weeks was significantly associated with a high score on any 1 of 3 constructs: MV-I, MV-D, and FV-I. Spontaneous preterm delivery at <35 weeks was significantly associated with a high score on 2 or more of 3 constructs: MV-I, MV-D, and FV-I; adjusted odds ratios ranged from 4.1 to 7.4. These results support a role for various placental vascular lesions in medically indicated and spontaneous preterm delivery.

Pregnancy complications associated with hepatitis C: data from a 2003-2005 Washington state birth cohort

OBJECTIVE

The objective of the study was to determine the effect of hepatitis C virus (HCV) on selected maternal and infant birth outcomes.

STUDY DESIGN

This population-based cohort study using Washington state birth records from 2003 to 2005 compared a cohort of pregnant women identified as HCV positive from birth certificate data (n = 506) to randomly selected HCV-negative mothers (n = 2022) and drug-using HCV-negative mothers (n = 1439).

RESULTS

Infants of HCV-positive mothers were more likely to be low birthweight (odds ratio [OR], 2.17; 95% confidence interval [CI] 1.24, 3.80), to be small for gestational age (OR, 1.46; 95% CI, 1.00, 2.13), to need assisted ventilation (OR, 2.37; 95% CI, 1.46, 3.85), and to require neonatal intensive car unit (NICU) admission (OR, 2.91; 95% CI, 1.86, 4.55). HCV-positive mothers with excess weight gain also had a greater risk of gestational diabetes (OR, 2.51; 95% CI, 1.04, 6.03). Compared with the drug-using cohort, NICU admission and the need for assisted ventilation remained associated with HCV.

CONCLUSION

HCV-positive pregnant women appear to be at risk for adverse neonatal and maternal outcomes.

Placental pathology, a survival guide

Placental pathology continues to be an underutilized, undertaught, and inadequately handled surgical subspecialty. The requests for placental pathology are soaring, due partly to demands from obstetricians and to the litigious environment in which they practice, and to improved obstetrical care leading to pregnancies in medically challenging situations. Evaluation of the placenta requires a good understanding of the questions and issues concerning both the fetus/infant and the mother. Information from placental pathology can be critical in early neonatal care and in reproductive planning for the family, and it can provide risk assessment for neurologic outcome of the infant. A comfortable interaction among the obstetric staff, mothers, and pathologists often obviates need for legal intervention in unexpected pregnancy outcomes. Some critical pathologic features that involve maternal and fetal management are illustrated herein. A template for gross examination and a few critical histopathologic diagnostic features with clincopathologic correlation are included.

The placenta as witness

The placenta not only "records" and reflects the intrauterine environment, it also provides valuable information on the cause and timing of many adverse events and conditions. The placenta may be useful in several ways. It may be the cause of injury due to an inherent abnormality, it may "malfunction" because of disease processes that are not primarily placental in origin, or it may merely reflect an abnormal intrauterine environment. Not only may the etiology of the injury be ascertained from placental examination, but also a time frame during which the abnormal condition has been operating. Acute lesions may be associated with sudden catastrophic events, whereas other, more chronic lesions lead to decreased placental reserves. Markedly depleted reserves will render the infant susceptible to other, sometimes more acute, events and thus are also associated with significant injury or even death.

Placental histopathologic features in patients with thrombophilic mutations

The purpose of this article is to review the histopathologic findings in the placenta of women with a known thrombophilic mutation. The findings range from normal to severe pathologic features including decidual vasculopathy, placental infarctions, syncytial knotting, maternal floor infarction, fetal thrombotic vasculopathy, vasculitis, and chronic villitis. They are, however, not pathognomonic of thrombophilic states, nor are necessarily markers of perinatal damage. The prospective evaluation of cases with known thrombophilic mutations and the application of tissue microarray examination of the placenta may allow identification of major histopathologic features and molecular parameters associated with maternal and/or fetal thrombophilic states. This may assist clinicians in their consultation with patients and optimize management in future pregnancies.

Clinical significance of placental examination in perinatal medicine

Complete pathologic evaluation of the placenta provides valuable information for perinatal care for the obstetrician, neonatologist, pediatrician, and family. The histopathology of the placenta can answer specific questions about in utero insults, give insight into management of subsequent pregnancies, and provide an assessment of the newborn risk. Placental pathology has been a key litigious informant in inferring timing of insults. Despite these well known advantages of placental pathologic examination, it remains an under-utilized part of perinatal medicine. This stems from a historically under-taught part of surgical and autopsy pathology resulting in inadequate reporting. This review will focus on the utility of the placental examination for fetal and maternal well-being. This review will be restricted to singleton births.

Stillbirths with placental hemorrhagic endovasculitis: a morphologic assessment with clinical implications

CONTEXT

Hemorrhagic endovasculitis (HEV) is a vasodisruptive alteration affecting fetal-placental blood vessels of all calibers. Hemorrhagic endovasculitis is found in association with stillbirth and abnormalities of growth and development in livebirths. The role of HEV in the pathogenesis of these conditions is not known.

OBJECTIVE

To further understand these events, we compare clinicopathologic features of HEV-affected placentas from stillbirths with those from livebirth pregnancies. Additionally, we assess the relationship of morphologic forms of HEV to clinical events and time of fetal death in utero and evaluate the significance of extensive versus localized HEV lesions in placentas of stillbirths.

DESIGN

We reviewed the clinical records and slides from 119 stillbirths with placentas affected by HEV classified above a specified severity level (cases) and 119 matched stillbirths with placentas not affected by HEV (controls). A subset of 21 stillbirth placentas exhibiting focal HEV lesions was similarly evaluated. Slides were graded for HEV, villitis of unknown etiology, chorionic thrombi, villous fibrosis, erythroblastosis, and lesions indicative of maternal hypertension. Hemorrhagic endovasculitis was subcategorized into active, bland, and healed forms and clustered capillary lesions (hemorrhagic villitis). Focal, segmental, and diffuse patterns of villous fibrosis were delineated. Interlesional relationships were established by matching HEV severity indices with severity indices of co-existing lesions. Timing of fetal death was determined by published criteria. Data were analyzed for significance using chi2 and t tests. Results were compared with published analyses of livebirths with placental HEV.

RESULTS

Lesions occurring with significant frequency in HEV-affected (case) placentas include villitis of unknown etiology, chorionic thrombi, villous fibrosis, erythroblastosis, and meconium staining. Interlesional relationships were evident between HEV and villous fibrosis, villitis of unknown etiology, and chorionic thrombi. Growth restriction was more common in case versus control infants (P = .02). A segmental pattern of villous fibrosis predominated in cases versus controls and within the case group (P < .001). Time to delivery after fetal death was longer in cases than controls. Active-vasodestructive forms of HEV correlate with shorter intervals of intrauterine retention, whereas bland forms correlate with longer intervals (P = .04). Placentas with focal HEV were associated with coexisting chorionic thrombi and villous fibrosis but not with fetal growth restriction.

CONCLUSIONS

Patterns of interlesional interplay are similar in HEV-affected placentas of livebirths and stillbirths. This suggests that the pathogenesis of infant morbidity and mortality is similar in both groups. Active-vasodestructive forms of HEV may precede whereas bland forms may follow intrauterine demise. The segmental pattern of villous fibrosis and high incidences of growth restriction, erythroblastosis, and meconium in cases suggests a chronicity of adverse intrauterine events that may precede fetal loss. Stillbirths with focal HEV lesions are probably not at risk.

Fatal fetal hemorrhage and placental pathology. Report of three cases and a new setting

We report three cases of late third trimester fetal death in utero consequent to fetal exsanguination from the chorionic vasculature. In general, fetal hemorrhage is unusual, exsanguination is rare and the location and basis of the hemorrhage varies widely. Intragestational and intrapartum hemorrhage is far more often of maternal rather than fetal origin. Even when severe, the former is almost always manageable whilst the latter may be clinically obscure, intractable, catastrophic and fatal. In this presentation, we review and characterize fetal hemorrhage by anatomical location and on the basis of its underlying origins. In our first two cases, the chorionic vascular failure is understood on the basis of mechanical factors, such as tearing by the presenting part or an amniotomy hook. Our third case demonstrates the first reported instance in which a severe chorionic vasculopathy has damaged a placental surface vessel sufficiently to permit spontaneous rupture and fetal exsanguination.

Best practice no 178. Examination of the human placenta

The human placenta is an underexamined organ. The clinical indications for placental examination have no gold standards. There is also inconsistency in the histological reports and the quality is variable. There is great interobserver variability concerning the different entities. Although there are still grey areas in clinicopathological associations, a few mainstream observations have now been clarified. The histopathological examination and diagnosis of the placenta may provide crucial information. It is possible to highlight treatable maternal conditions and identify placental or fetal conditions that can be recurrent or inherited. To achieve optimal benefit from placental reports, it is essential to standardise the method of placenta examination. This article summarises the clinical indications for placenta referral and the most common acknowledged clinicopathological correlations.

Fetal vascular obstructive lesions: nosology and reproducibility of placental reaction patterns

The purpose of this study was to assemble and test the reliability of a complete set of the placental reaction patterns seen with chronic fetal vascular obstruction in the hope that this might provide a standardized diagnostic framework useful for practicing pathologists. Study cases (14 with fetal vascular obstructive lesions, 6 controls) were reviewed blindly by seven pathologists after agreement on a standard set of diagnostic criteria. Majority vote served as the gold standard and 80% of the 180 diagnoses rendered (9 diagnoses each for 20 cases) were agreed upon by at least six of the seven scores. The sensitivity of individual diagnosis relative to the group consensus averaged 83% (range, 69-100%) and specificity averaged 91% (range, 86-100%). Reproducibility was measured by unweighted kappa-values and interpreted as follows: < 0.2, poor; 0.2-0.6, fair/moderate; > 0.6, substantial. Kappa values for lesions of distal villi were generally superior to those for lesions involving large fetal vessels: avascular villi (0.49), villous stromal-vascular karyorrhexis (0.58), and villitis of unknown etiology (VUE) with stem villitis and avascular villi (0.65) versus large vessel thrombi (any vessel, 0.34; chorionic plate vessel, 0.40) and intimal fibrin cushions (recent, 0.47; remote, 0.78). Reproducibility for a global impression of any villous change consistent with chronic fetal vascular obstruction was substantial (0.63), while that for a more severe subgroup was moderate (0.44). Three points are worthy of emphasis. Our system separately recognizes, but later combines, uniformly avascular villi and villous stromal-vascular karyorrhexis as manifestations of the same underlying process. We propose that this combined group of villous lesions be dichotomized with the terms fetal thrombotic vasculopathy or extensive avascular villi (and/or villous stromal-vascular karyorrhexis) being reserved for the group with 15 or more affected terminal villi per section. Scattered foci of avascular villi (and/or villous stromal-vascular karyorrhexis) could be used to describe less severe cases. Finally, we distinguish VUE with stem villitis and avascular villi (obliterative fetal vasculopathy) as a distinct process with substantial perinatal morbidity.

Placental pathology: its impact on explaining prenatal and perinatal death

This review considers six main situations in which pathologists are expected to report and interpret placental messages for obstetricians, neonatologists and, indirectly, parents: (1) abortion is the body's corrective response to the embryonic defect suggested by malformed chorionic villi; (2) infection causing chorionic villous inflammation is specific and haematogenous; pathogen identification is mandatory, in contrast to chorioamnionitis caused by increased local immunosuppression allowing indiscriminate bacterial entry; (3) prematurity and (4) intrauterine growth restriction are often associated with pregnancy-specific disease (pre-eclampsia) or pre-existing maternal conditions (systemic lupus); parental studies may improve outcome in subsequent pregnancies; (5) intrauterine death near term is often due to placental dysmaturity featuring a severely reduced number of syncytiocapillary membranes; it accounts for the death in utero of 3 in 1000 pregnancies; detection helps to minimise recurrence in subsequent pregnancies; (6) twins are best confirmed as monozygous by the absence of chorionic tissue in the dividing membranes; most monochorionic twins have vascular connections whose detailed analysis is requested only if there are inter-twin differences in growth and colour. From a formal point of view, many more bits of pathology than discussed in this review can be found in placentas and, with the advances in ultrasonography, might even be seen prior to birth. The extent of such a disturbance might ultimately affect fetal growth, which is amenable to prenatal detection offering the chances for an appropriate management. In contrast, dysmaturity is a great challenge as no predictive tests are as yet available.