Frequency of factor V(Leiden) and prothrombin G20210A in placentas and their relationship with placental lesions

Placental MRI segmentation based on multi-receptive field and mixed attention separation mechanism

OBJECTIVE

To reduce the occurrence of massive bleeding during placental abruption in patients with placenta accrete, we established a medical imaging based on multi-receptive field and mixed attention separation mechanism (MRF-MAS) model to improve the accuracy of MRI placenta segmentation and provide a basis for subsequent placenta accreta.

METHODS

We propose a placenta MRI segmentation technology using the MRF-MAS framework to develop a medical image diagnostic technique. The model first uses the multi-receptive field feature structure to obtain multi-level information, and improves the expression of features at differing scales. Note that the hybrid attention mechanism combines channel attention and spatial attention, separates the input feature sets and computes the attention separately, and finally reorganizes the feature maps. To show that the model can improve the accuracy of segmenting the placenta, we adopt mean Intersection over Union (IoU), Dice similarity coefficient (Dice) and area under the receiver operating characteristic curve (AUC) with U-Net, Mask RCNN, Deeplab v3 for comparison.

RESULTS

The four models achieved different outcomes based on our placenta dataset, with our model IoU and Dice up to 0.8169 and 0.8992, which are 5.51% and 3.03% higher than the average of the three comparison models.

CONCLUSION

The model proposed by us is helpful to assist the imaging diagnosis and at the same time provides a quantitative reference for the precise treatment of placenta accreta, assists the Equationtion of the clinical operation plan of the physician, and promotes the precision medicine of placenta accreta.

Ultrasound Doppler Findings in Fetal Vascular Malperfusion Due to Umbilical Cord Abnormalities: A Pilot Case Predictive for Cerebral Palsy

Fetal Vascular Malperfusion (FVM), a pathologic condition in the feto-placental circulation, is a chronic vaso-occlusive disorder in the umbilical venous blood flow. Microthrombi are caused by the umbilical cord's blood flow deficiency in a congested umbilical vein, which also causes microvascular damage to fetal organs, especially the brain, resulting in cerebral palsy. Thrombo-occlusive events also adversely affect the upstream chorionic or stem vessels in the placenta, resulting in fetal growth restriction and fetal hypoxia. An umbilical cord structural anomaly or multiple entanglements may involve FVM. In the present report, we demonstrate a case of FVM caused by multiple umbilical cord abnormalities obtained from antenatal ultrasound Doppler findings, and we also discuss FVM, which is chronically associated with CP, comparing the ultrasonographic findings to the pathologic findings.

Molecular Mechanisms Underlying Twin-to-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome is a unique disease and a serious complication occurring in 10–15% of monochorionic multiple pregnancies with various placental complications, including hypoxia, anemia, increased oxidative stress, and ischemia-reperfusion injury. Fetoscopic laser photocoagulation, a minimally invasive surgical procedure, seals the placental vascular anastomoses between twins and dramatically improves the survival rates in twin-to-twin transfusion syndrome. However, fetal demise still occurs, suggesting the presence of causes other than placental vascular anastomoses. Placental insufficiency is considered as the main cause of fetal demise in such cases; however, little is known about its underlying molecular mechanisms. Indeed, the further association of the pathogenic mechanisms involved in twin-to-twin transfusion syndrome placenta with several molecules and pathways, such as vascular endothelial growth factor and the renin–angiotensin system, makes it difficult to understand the underlying pathological conditions. Currently, there are no effective strategies focusing on these mechanisms in clinical practice. Certain types of cell death due to oxidative stress might be occurring in the placenta, and elucidation of the molecular mechanism underlying this cell death can help manage and prevent it. This review reports on the molecular mechanisms underlying the development of twin-to-twin transfusion syndrome for effective management and prevention of fetal demise after fetoscopic laser photocoagulation.

What Obstetricians Need to Know About Placental Pathology

The placenta can serve as a valuable source of information about maternal and fetal conditions during the pregnancy; however, the abilities to perform a preliminary gross examination and interpret a placental pathology report are variable among obstetricians. This article discusses the indications for placental submission to pathology; the essentials of gross examination, including elements that should be performed in the delivery suite; and the most common and clinically relevant histologic findings that may be encountered in the report.

Temporal heterogeneity of placental segmental fetal vascular malperfusion: timing but not etiopathogenesis

Clinicopathologic correlations of segmental villous avascularity and other histological lesions of segmental fetal vascular malperfusion (SFVM) were analyzed retrospectively to determine whether lesions of various durations reflect different etiopathogeneses. The frequencies of 25 independent clinical and 43 placental phenotypes were statistically compared by ANOVA or Chi-square among 3 groups containing a total of 378 placentas with SFVM: group 1 contained 44 cases of recent SFVM (endothelial fragmentation, villous hypovascularity by CD34 immunostain, and/or stromal vascular karyorrhexis); group 2 contained 264 cases of established SFVM (clusters of avascular villi); and group 3 contained 70 cases of remote SFVM (villous mineralization). Statistically significant differences among the three study groups (p Bonferroni < 0.002) were found in four clinical variables (gestational age, frequencies of macerated stillbirth, induction of labor, and cesarean section) and in five placental variables (frequencies of fetal vascular ectasia, stem vessel luminal vascular abnormalities, diffusely increased extracellular matrix in chorionic villi, chorionic disk extravillous trophoblast microcysts, and excessive extravillous trophoblasts in the chorionic disc). In summary, the absence of statistically significant differences between the study groups regarding the most common causes of SFVM (hypertensive conditions of pregnancy, diabetes mellitus, fetal anomalies, and clinical and pathological features of umbilical cord compromise) is evidence that the three types of SFVM reflect temporal heterogeneity rather than etiopathogenesis. This evidence can be used to date the onset of fetal vascular malperfusion before delivery or stillbirth. The coexistence of different SVFM lesions of various durations indicates ongoing or repeat occurrences of FVM rather than single episodes.

May the morphological findings in the first-trimester abortion materials be indicative of inherited thrombophilia?

PURPOSE

İnherited thrombophilia is associated with severe pregnancy complications including recurrent spontaneous abortion. In the light of this strong association, the impact of thrombophilic mutations on the placenta and their morphological reflections has aroused attention of both clinicians and pathologists. In the present study, we aimed to show the association between placental abnormalities with thrombophilia by examining the morphological findings in a wide range of first-trimester chorionic villi.

METHODS

We performed a histological examination on the abortion specimens obtained from 129 patients with recurrent pregnancy losses that were evaluated with respect to inherited thrombophilia based on the presence of Factor V Leiden (G1691A), Prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T gene mutations detected by genetic analysis. Abortion materials either with and without thrombophilia were evaluated in terms of the morphological parameters such as hydropic change, vascularity, fibrosis, fibrinoid degeneration, Hofbauer macrophage, syncytiotrophoblast knotting, villitis, calcification, villous contour and villous size, hemorrhage, thrombus, proliferation of trophoblasts, villous stromal or villous vascular karyorrhexis.

RESULTS

No statistically significant difference was found between the patient groups with and without thrombophilia in terms of morphological findings except vascularity of chorionic villi. The avascular chorionic villi (<3 vessels per villus) were found in 62.9% and 16.9% obtained from the women with and without thrombophilic mutation, respectively. This difference was statistically significant (P < 0.001).

CONCLUSION

As a conclusion, it could be stated that the analysis of morphological findings in the abortion specimen is not a time-wasting process. Particularly, data related with vascularity of chorionic villi would be precious and beneficial. We suggest that highlighting the presence of avascular villi in the pathology report as a parameter would be guiding for clinicians regarding the impact of the thrombophilic gene mutations.

Predictors of High Grade and Other Clinically Significant Placental Findings by Indication for Submission in Singleton Placentas From Term Births

Indications for placental submission are variable. Established guidelines are largely based on expert opinion, and there is a need for more evidence-based criteria. A 10-year database of term placentas was used to evaluate indications significantly associated with placental pathology. Lesions in 5 categories were separated into high- and low-grade subgroups. Two additional high-grade lesions were also evaluated. Indications associated with high-grade placental lesions were chronic monitoring abnormalities, severe preeclampsia, pregestational diabetes, maternal signs of infection, postdates pregnancy, artificial reproductive technology, drug abuse, umbilical cord entanglements, selected gross placental abnormalities, stillbirth, Apgar 5 minutes <6, small-for-gestational age infant, and macrosomia. Indications for which placental findings did not differ from the population as a whole were acute monitoring abnormalities, chronic hypertension, maternal obesity, vaginal bleeding, accessory lobe/multilobed placenta, meconium-stained fluid, single umbilical artery, and borderline large-for-gestational age infant. Other indications for submission were intermediate showing significant or borderline elevations in the prevalence of low- and high-grade lesions combined. We suggest on the basis of this study that guidelines for the submission of singleton term placentas could be modified to exclude cases with clinical indications that lack a significant association with placental lesions.

CD34 immunostain increases the sensitivity of placental diagnosis of fetal vascular malperfusion in stillbirth

INTRODUCTION

Postmortem regressive placental changes of stillbirth may obscure the pre-existing placental histomorphology. The objective is to find out whether the use of CD34 immunostain can increase the sensitivity of placental examination in the diagnosis of fetal vascular malperfusion (FVM).

METHODS

Twenty six independent clinical and 46 placental variables of 46 placentas from stillbirths were statistically compared to those of 92 placentas from livebirths. One histologically most unremarkable section per case was stained using double E-cadherin/CD34 immunostain (ECCD34). Clusters of avascular/hypovascular chorionic villi on hematoxylin and eosin (H&E) staining system and/or CD34 immunostaining, the latter also including endothelial CD34 positive debris in the villous stroma, were regarded as evidence of FVM.

RESULTS

The gestational age and cesarean section rate were statistically significantly lower and the induction of labor and mild erythroblastosis of fetal blood was higher, but the frequencies of clinical and placental features of umbilical cord compromise were not statistically significant between stillbirths and livebirths, respectively. By using H&E stain, 9 (19.6%) of stillbirths and 30 (32.6%) of livebirths showed clusters of avascular villi on H&E. By CD34, the rates of FVM increased to 23 (50%) and 34 (40%), respectively. The increase was statistically significant for stillbirths only (Chi square = 9.4, p = 0.002). By CD34, new clusters of hypovascular chorionic villi or villi with endothelial fragmentation were found in 23 stillbirth cases (50%) as opposed to livebirths (29 cases, 31.5%)(Chi square = 9.4, p = 0.002).

DISCUSSION

When compared with H&E stain, the CD34 increases sensitivity and/or upgrades FVM in placental examination in stillbirths but not in livebirths.

The Placenta in Neonatal Encephalopathy: A Case-Control Study

OBJECTIVE

We assessed whether specific histologic placental lesions were associated with risk for neonatal encephalopathy, a strong predictor of death or cerebral palsy.

STUDY DESIGN

Case-control study of singletons with gestational ages ≥35 weeks. Data were abstracted from a prospectively collected database of consecutive births at a hospital in which placental samples from specified sites are collected and stored for all inborn infants. Placentas of infants with neonatal encephalopathy were compared with randomly selected control infants (ratio of 1:3). Placental histologic slides were read by a single experienced perinatal pathologist unaware of case status, using internationally recommended definitions and terminology. Findings were grouped into inflammatory, maternal, or fetal vascular malperfusion (FVM) and other lesions.

RESULTS

Placental samples were available for 73 of 87 (84%) cases and 253 of 261 (97%) controls. Delivery complications and gross placental abnormalities were more common in cases, of whom 4 died. Inflammation and maternal vascular malperfusion did not differ, and findings consistent with global FVM were more frequent in case (20%) than control (7%) placentas (P = .001). There was a trend toward more segmental FVM and high-grade FVM (fetal thrombotic vasculopathy) among cases. Some type of FVM was observed in 24% of placentas with neonatal encephalopathy. In infants with both neonatal encephalopathy and placental FVM, more often than in infants with neonatal encephalopathy without FVM, electronic fetal monitoring tracings were considered possibly or definitely abnormal (P = .028).

CONCLUSIONS

Vascular malperfusion of subacute or chronic origin on the fetal side of the placenta was associated with increased risk of neonatal encephalopathy.

Fetal vascular malperfusion, an update

Fetal vascular malperfusion is the most recent term applied to a group of placental lesions indicating reduced or absent perfusion of the villous parenchyma by the fetus. The most common etiology of malperfusion is umbilical cord obstruction leading to stasis, ischemia, and in some cases thrombosis. Other contributing factors may include maternal diabetes, fetal cardiac insufficiency or hyperviscosity, and inherited or acquired thrombophilias. Severe or high grade fetal vascular malperfusion is an important risk factor for adverse pregnancy outcomes including fetal growth restriction, fetal CNS injury, and stillbirth. Overall recurrence risk for subsequent pregnancies is low.

Fetal Vascular Malperfusion

CONTEXT

- Fetal vascular malperfusion, also known as fetal thrombotic vasculopathy, remains an underrecognized pathologic finding and should be noted during placental evaluation.

OBJECTIVE

- To review histologic findings, gain familiarity with the updated terminology, and to recognize important clinical associations with this entity.

DATA SOURCES

- University of Michigan cases, PubMed search, multiple review articles including recent placental workshop group consensus statement, and selected book chapters.

CONCLUSIONS

- Multiple histologic patterns of fetal vascular malperfusion have been described including thrombosis, avascular villi, villous stromal-vascular karyorrhexis, intramural fibrin thrombi, and stem villous vascular obliteration. Various underlying etiologies can be involved in fetal vascular malperfusion. Cord lesions including abnormal insertion, length, and coiling are important causes. Maternal vascular malperfusion such as preeclampsia, hypercoagulable states, lupus anticoagulant, and sometimes diabetes have been associated with this condition. Fetal cardiac dysfunction/malformations and severe fetal inflammatory response in the setting of ascending intrauterine infection have also been attributed to this important finding. Fetal vascular malperfusion has been implicated in several significant and sometimes devastating clinical associations; these include intrauterine growth restriction, poor perinatal outcome, fetal demise, and neurodevelopmental sequelae. A diagnostic challenge may be encountered in cases with prior intrauterine fetal death, since degenerative changes post demise result in a similar histomorphologic picture. The diffuse versus the focal nature of the lesions may help in the distinction.

Placental Pathology Associated with Household Air Pollution in a Cohort of Pregnant Women from Dar es Salaam, Tanzania

BACKGROUND

Smoke from the burning of biomass fuels has been linked with adverse pregnancy outcomes such as low birth weight, stillbirth, and prematurity.

OBJECTIVE

To identify potential underlying mechanisms of adverse perinatal outcomes, we explored the association of placental pathology with household air pollution in pregnant women from urban/periurban Tanzania who cook predominantly with charcoal.

METHODS

Between 2011 and 2013, we measured personal exposures to fine particulate matter (PM2.5) and carbon monoxide (CO) over 72 hr among a cohort of Tanzanian pregnant women. Placentas were collected after delivery for examination. Placental pathologies of inflammatory, hypoxic, ischemic/hypertensive, infectious and thrombotic etiologies were diagnosed, blinded to exposure levels. Using multiple logistic regression, we explored the association of PM2.5 and CO exposure with placental pathology.

RESULTS

One hundred sixteen women had personal air exposure measurements and placental histopathology available for analysis. PM2.5 and CO exposures were moderate [geometric means (GSD) were 40.5 μg/m3 (17.3) and 2.21 ppm (1.47) respectively]; 88.6% of PM2.5 measurements exceeded World Health Organization air quality guidelines. We observed an increase in the odds (per 1-unit increase in exposure on the ln-scale) of fetal thrombotic vasculopathy (FTV) both with increasing PM2.5 [adjusted odds ratio (aOR) = 5.5; 95% CI: 1.1, 26.8] and CO measurements (aOR = 2.5; 95% CI: 1.0, 6.4) in adjusted models only. FTV also was more common among pregnancies complicated by stillbirth or low birth weight.

CONCLUSIONS

Fetal thrombosis may contribute to the adverse outcomes associated with household air pollution from cook stoves during pregnancy. Larger studies are necessary for confirmation. Citation: Wylie BJ, Matechi E, Kishashu Y, Fawzi W, Premji Z, Coull BA, Hauser R, Ezzati M, Roberts D. 2017. Placental pathology associated with household air pollution in a cohort of pregnant women from Dar es Salaam, Tanzania. Environ Health Perspect 125:134-140; http://dx.doi.org/10.1289/EHP256.

Fetal Thrombotic Vasculopathy: Perinatal Stroke, Growth Restriction, and Other Sequelae

Clots in the fetal circulation of the placenta may occlude or narrow the lumens of fetal vessels sufficiently to diminish the placental oxygen and nutritional exchange, causing significant reduction in placental function. When extensive, growth restriction, neonatal encephalopathy, and stillbirth may occur. Propagation of clots in other organs, such as brain, kidney, and liver, may affect the function of these organs, resulting in infarcts and neonatal stroke. This article presents an account of the placental pathology and clinical sequelae of this condition, called fetal thrombotic vasculopathy.

Extensive Thrombosis of the Inferior Vena Cava and Left Renal Vein in a Neonate

Antenatal renal vein thrombosis is a rarely described diagnostic finding, with variable consequences on kidney function. We present the case of an affected fetus, born at 35-week gestation, with intrauterine oligohydramnios and two small kidneys. A renal ultrasound carried out after birth confirmed the presence of prenatal abnormalities. Renal vein thrombosis was not diagnosed at the time. The baby died 20 days later of kidney failure, metabolic acidosis, and polypnea with severe hypotrophy. Autopsy revealed atrophied kidneys and adrenal glands. The vena cava had thrombosis occupying most of its length. The right renal vein was normal, while the left renal vein was threadlike and not permeable. Histologically, there was necrosis of the left adrenal gland with asymmetrical bilateral renal impairment and signs of ischemic and hemorrhagic lesions. A review of thrombophilia was carried out and a heterozygous mutation in Factor V was found in both the mother and the child.

The clinical implications of placental diagnoses

The clinical utility of placental pathology is both overestimated and underestimated, and the overall quality of placental pathology reporting, even at major medical centers, is highly variable. Clear benefits of examining placentas include the immediate diagnosis of treatable conditions in both the mother and the infant, clarification of the underlying etiology of adverse pregnancy outcomes, estimation of recurrence risk, and guidance for the management of future pregnancies. In order to realize these benefits and get the most out of their pathology departments, it is critical for clinicians to understand the range and implications of placental lesions. This article will review the nomenclature, diagnostic criteria and pitfalls, and clinical significance of seven common placental disease processes and a handful of other lesions.

Placental lesions associated with acute atherosis

OBJECTIVE

Acute atherosis is a lesion of the spiral arteries characterized by fibrinoid necrosis of the vessel wall, an accumulation of fat-containing macrophages, and a mononuclear perivascular infiltrate, which can be found in patients with preeclampsia, fetal death, small-for-gestational age, spontaneous preterm labor/premature prelabor rupture of membrane, and spontaneous mid-trimester abortion. This lesion is thought to decrease blood flow to the intervillous space which may lead to other vascular lesions of the placenta. The objective of this study was to test whether there is an association between acute atherosis and placental lesions that are consistent with maternal vascular underperfusion (MVU), amniotic fluid infection (AFI), fetal vascular thrombo-occlusive disease (FVTOD) or chronic inflammation.

MATERIAL AND METHODS

A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women's Hospital/Detroit Medical Center was conducted examine 16 457 placentas. The frequency of placenta lesions (diagnosed using the criteria of the Perinatal Section of the Society for Pediatric Pathology) was compared between pregnancies with and without acute atherosis.

RESULTS

Among 16 457 women who were enrolled, 10.2% (1671/16 457) were excluded, leaving 14 786 women who contributed data for analysis. Among them, the prevalence of acute atherosis was 2.2% (326/14 786). Women with acute atherosis were more than six times as likely as those without to have placental lesions consistent with maternal underperfusion (adjusted odds ratio - aOR: 6.7; 95% CI 5.2-8.6). To a lesser degree, acute atherosis was also associated with greater risks of having either lesions consistent with FVTOD (aOR 1.7; 95% CI 1.2-2.3) or chronic chorioamnionitis (aOR 1.9; 95% CI 1.3-3), but not with other chronic inflammatory lesions, after adjusting for gestational age at delivery. In contrast, women with acute atherosis were 60% less likely to have lesions consistent with AFI, adjusting for gestational age at delivery (aOR 0.4; 95% CI 0.3-0.5).

CONCLUSIONS

Acute atherosis is associated with increased risks of having placental lesions consistent with MVU, and to a lesser extent, chronic chorioamnionitis and those consistent with FVTOD.

Fetal thrombotic vasculopathy is associated with thromboembolic events and adverse perinatal outcome but not with neurologic complications: a retrospective cohort study of 54 cases with a 3-year follow-up of children

OBJECTIVE

to test the hypothesis that placental fetal thrombotic vasculopathy (FTV) is associated with obstetric complications and predisposes the child to unfavorable outcomes.

METHODS

54 placentas with FTV lesions and 100 placentas without FTV lesions were collected over a 5-year period at the Croix-Rousse Pathology Department. Clinical findings including maternal, fetal, neonatal condition and pediatric outcome up to three years were collected for each case and control observation. The statistical analyses were assessed with Wald's chi-square derived from conditional logistic regression modeling.

RESULTS

FTV was associated with a significantly higher frequency of obstetric complications: (pregnancy-induced hypertension (OR 3.620, CI 1.563-8.385), preeclampsia (OR 3.674, CI 1.500-8.998), emergency delivery procedures (OR 3.727, CI 1.477-9.403), cesarean sections (OR 2.684, CI 1.016-7.088)), poor fetal condition (intrauterine growth restriction (IUGR) (OR 5.440, CI 2.007-14.748), nonreassuring fetal heart tracing (OR 6.062, CI 2.280-16.115), difficulties in immediate ex utero adaptation (OR 3.416, CI 1.087-10.732)) and perinatal or early childhood demise (OR 3.043, CI 1.327-6.978). On pathological examination, FTV was associated with marginal cord insertion (OR 3.492, CI 1.350-9.035), cord stricture and hypercoiled cord (OR 3.936, CI 1.209-12.813). Thromboembolic events were significantly more frequent in cases with FTV (OR 2.154, CI 1.032-5.622). Neurological complications within the first 3 years of life were also more frequent in the FTV group compared to the control group, but this association was not statistically significant.

CONCLUSIONS

FTV is associated with maternal complications, pathological findings in the placenta, especially gross cord abnormalities, IUGR, and poor perinatal or early childhood outcome. It may also predispose children to somatic thromboembolic events.

Correlation of Placental Pathology with Perinatal Brain Injury

The purpose of placental pathology is to explain adverse clinical outcomes. One of the most tragic of these outcomes is perinatal brain injury with subsequent neurodisability. Findings in the placenta can play an important role in documenting sentinel events, uncovering clinically silent thromboinflammatory disease processes, revealing developmental alterations in functional reserve, and suggesting alterations in related maternal and fetal physiology. These findings, when integrated with clinical data, provide a plausible explanation for an otherwise unexpected outcome and can be helpful for treating physicians and family members.

Intestinal atresia occurring in association with placental fetal thrombotic vasculopathy: a case report with literature review

Fetal thrombotic vasculopathy (FTV) is a thrombo-occlusive disorder of the placenta that has been reported in association with perinatal conditions such as cardiac abnormalities, neurological injury, and perinatal liver disease. These complications are related to fetal circulation vascular compromise. We herein report a previously undocumented association of congenital intestinal atresia and placental FTV. Vascular occlusion of the fetal mesenteric vessels has been hypothesized to result in congenital intestinal atresia. Our report provides support for this vascular hypothesis and illustrates the value of formal pathological examination of the placenta in explaining this occurrence of congenital intestinal atresia.

Placental histologic criteria for diagnosis of cord accident: sensitivity and specificity

"Cord accident" (compromised umbilical blood flow) as a cause of stillbirth is underreported, mainly due to a lack of diagnostic criteria. Based on fetal vascular pathology in the placenta, we have previously established histologic criteria for the diagnosis of cord accident. In the current study, we set out to test the sensitivity and specificity of these criteria by reviewing an independent set of stillbirth cases. Placental slides from 26 cases (in which cord accident was deemed the cause of death) and 62 controls (in which the cause of death was anything other than cord accident) were reviewed. The following histologic changes were noted: (1) dilated fetal vessels, (2) thrombosis in fetal vessels, and (3) avascular or near-avascular chorionic villi. "Minimal" criteria were defined as the presence of dilated and thrombosed fetal vessels, while the additional presence of focal or regional avascular or near-avascular villi satisfied the complete criteria. Of the 62 stillbirth controls with cause of death other than cord accident, 13 (21%) met the minimal criteria (specificity 79%) and only 4 (6%) met the complete criteria for cord accident (specificity 94%). In contrast, of the 26 cases with a cause of death related to cord accident, 16 met the minimal criteria (sensitivity 62%) and 12 met the complete criteria (sensitivity 46%). These histologic criteria identify cases of cord accident as a cause of stillbirth with very high specificity. This study confirms the utility of these criteria for diagnosis of cord accident and further stresses placental examination in evaluation of stillbirths.

Placental pathology in neonatal stroke

OBJECTIVE

Neonatal stroke is increasingly recognized, and risk factors have been identified. The placenta has been implicated as a potential contributor to neonatal stroke; however, pathology has not been previously described. This case series systematically evaluates prenatal, maternal, and neonatal risk factors and describes placental pathology in 12 cases of neonatal stroke.

PATIENTS AND METHODS

We reviewed the Canadian Pediatric Ischemic Stroke Registry from 1992 to 2006, which consists of 186 neonatal stroke patients. Twelve patients with symptomatic cerebral arterial ischemic stroke or sinovenous thrombosis had their placenta available for pathologic examination. Clinical presentation; maternal, prenatal, and neonatal risk factors for stroke; and patient outcome were collected retrospectively from patient charts. Gross and microscopic placental pathology was described and classified into 4 pathologic categories.

RESULTS

Of 12 patients studied, 10 patients were male, 5 patients had arterial ischemic stroke, and 7 patients had sinovenous thrombosis. Maternal risk factors were identified in 5 cases, prenatal risk factors in 10 cases, and neonatal risk factors in 10 cases. Placental lesions were present in 10 cases and were classified as thromboinflammatory process in 6 cases, sudden catastrophic event in 5 cases, decreased placental reserve in 3 cases, and stressful intrauterine environment in 2 cases.

CONCLUSIONS

This study reviews detailed placental pathology in a selected cohort of patients presenting near the time of delivery and correlates this with clinical presentation, outcome, and risk factors for neonatal stroke. Our results suggest that multiple risk factors are involved in neonatal stroke, and placental pathology may be a contributing factor. The implications of specific placental lesions remain to be determined with larger, case-controlled studies.

Obstetric and perinatal complications in placentas with fetal thrombotic vasculopathy

Fetal thrombotic vasculopathy (FTV) is a placental lesion characterized by regionally distributed avascular villi and is often accompanied by upstream thrombosis in placental fetal vessels. Previous studies, using preselected populations, have shown associations of this lesion with adverse neurodevelopmental outcomes and potentially obstructive lesions of the umbilical cord. We investigated the prevalence of obstetric complications, perinatal disease, and placental abnormalities in cases with FTV. One hundred thirteen cases of placentas with FTV were identified in our pathology database over an 18-year period. Two hundred sixteen placentas without the diagnosis of FTV, frequency matched on year of birth, were selected as controls. Electronic medical records and pathology reports were used to extract maternal and gestational age, method of delivery, neonatal outcome, lesions of the umbilical cord, obstetric complications, and fetal abnormalities. Placentas with FTV were associated with a 9-fold increase in rate of stillbirth and a 2-fold increase in intrauterine growth restriction. The increase in pregnancy-induced hypertension/preeclampsia was not significant when adjusted for maternal and gestational age. Although the rate of potentially obstructive cord lesions was similar in both groups, there was an almost 6-fold increase in the presence of oligohydramnios in FTV placentas, compared with controls. Finally, FTV was associated with a 6-fold increase in fetal cardiac abnormalities. Fetal thrombotic vasculopathy is associated with a significantly higher rate of obstetric and perinatal complications. This study points to abnormal fetal circulation, either in the form of congenital heart disease or oligohydramnios predisposing to cord compression, as a risk factor for FTV.

Avascular villi, increased syncytial knots, and hypervascular villi are associated with pregnancies complicated by factor V Leiden mutation

There is controversy about whether pathologic abnormalities are associated with pregnancies complicated by factor V Leiden (FVL) mutation. The purpose of this study was to evaluate 105 placentas delivered to mothers heterozygous for FVL mutation to determine if there are pathologic changes suggestive of hypoxia or thrombosis, which correlate with mutation status. We examined placentas obtained as part of a prospective study of 5188 pregnancies analyzed for the presence of FVL mutation in either the mother or the infant. One hundred five placentas from mothers heterozygous for the mutation were compared with 225 controls matched for maternal age, race, and geographic site. Of the 330 pregnancies, 50 infants were FVL mutation heterozygotes. Maternal FVL heterozygote status was associated with more frequent increased numbers of syncytial knots (13% vs 4%); the difference remained significant after controlling for hypertension, preeclampsia, small-for-gestational-age infants, and delivery prior to 35 weeks of gestation (odds ratio 3.6, 95% confidence interval 1.5-8.7, P  =  0.004). Maternal FVL heterozygotes had more hypervascular villi (10% vs 3%), with significance retained controlling for delivery route (odds ratio 3.4, 95% confidence ratio 1.2-9.4, P  =  0.018). Placentas from infants heterozygous for FVL mutation had more avascular villi than controls (odds ratio 2.9, 95% confidence interval 1.5-5.6, P  =  0.001). Fetal or maternal FVL heterozygosity was not associated with infarcts, small-for-gestational-age placentas, or fetal thrombotic vasculopathy. This analysis demonstrates that pathologic findings associated with placental hypoxia, specifically focal avascular villi, increased numbers of syncytial knots, and hypervascular villi, also correlate with FVL heterozygosity in infants or mothers.

Massive fetal thrombotic vasculopathy associated with excessively long umbilical cord and fetal demise: case report and literature review

Both excessively long umbilical cord (ELUC) and fetal thrombotic vasculopathy (FTV) have been associated with adverse perinatal outcomes, in particular, fetal loss and long-term neurological complications. The etiologies of these conditions are unclear and are likely multifactorial. Excessively long umbilical cord has been associated with FTV and fetal demise, with cases generally showing other cord abnormalities and only localized FTV. We report a 37-week male stillborn fetus whose placenta had a 113-cm-long umbilical cord with no other cord abnormalities associated with "massive" FTV (ie, >25% of the placental mass). This case illustrates the unusual occurrence of FTV of such severe extent in association with ELUC leading to fetal demise. This case illustrates that ELUC alone may be enough to predispose the placenta to massive FTV.

Fetal placental thrombosis and neonatal implications

We present the neonatal complications of two premature newborn infants whose placentas demonstrated placental thrombosis in the fetal circulation. Both mothers presented with a 3-day history of decreased fetal movements before delivery. The first infant presented with thrombocytopenia and disseminated intravascular coagulation. The second infant had extended bilateral extended hemorrhagic venous infarctions. Severe fetal placental vascular lesions seem to be a predisposing factor for some adverse neonatal outcomes. We present these two cases with a brief review of the literature.

Maternal thrombophilias are associated with specific placental lesions

Maternal floor infarction (MFI), massive perivillous fibrin deposition (MPVFD), and fetal thrombotic vasculopathy (FTV) are specific placental lesions with associations to recurrent adverse fetal outcomes and with maternal thrombophilia. We studied the frequency of a range of acquired and genetic maternal thrombophilias in MFI (40 cases), MPVFD (87 cases), FTV (7 cases), and FTV+MPVFD (4 cases). Thrombophilias were identified in 16 (40%), 20 (23%), 5 (71%), and 2 (50%) of these lesions, respectively. Seventy-seven percent of the identified thrombophilias were genetic, and 23% were acquired. The most common genetic thrombophilia was protein S deficiency, which constituted 14 of the 36 genetic thrombophilias (39%). We advocate full maternal thrombophilia testing when the diagnosis of MFI, MPVFD, and FTV is made by placental pathology examination. Because of the possible contribution of paternal thrombophilic mutations to the fetal genotype, it would be desirable to test the whole family as well.

Familial perinatal liver disease and fetal thrombotic vasculopathy

The association between placental fetal thrombotic vasculopathy (FTV) and perinatal liver disease was not recognized until 2002, when Dahms and colleagues reported a series of 3 patients in whom severe liver disease developed in the first 2 days of life. All had abnormal liver histology and showed a variety of abnormalities, including Budd-Chiari syndrome, changes mimicking extrahepatic obstruction, lobular fibrosis, cholestasis, and hepatocyte giant cell transformation. We report recurrent significant perinatal liver disease in a family, associated with proven FTV in at least 1 pregnancy. A 30-year-old gravida 4 female with a history of heterozygous methylenetetrahydrofolate A1298C mutation had a normal 1st pregnancy and then experienced an intrauterine fetal demise at 38 weeks of gestation. Placental examination revealed extensive occlusive and mural thrombi of chorionic vessels associated with a large focus of avascular villi. Histologic examination of the liver showed extensive giant cell transformation and hepatocyte dropout. No excess hemosiderin pigment was present in the liver, pancreas, or heart. A 3rd pregnancy produced a live-born term infant with transient neonatal cholestasis. The 4th pregnancy also produced a term neonate who presented with acute hepatic failure of unknown cause, ultimately requiring liver transplantation. Fetal thrombotic vasculopathy is an underrecognized association with perinatal liver disease that may be associated with abnormal liver perfusion and that may recur in families, especially when a genetic thrombophilia is present.

Pathology of thrombotic thrombocytopenic purpura in the placenta, with emphasis on the snowman sign

Thrombotic thrombocytopenic purpura (TTP) commonly affects women of childbearing age. Although cases of TTP in pregnancy have been reported, the pathology of TTP in the placenta has not been described. In other organs, TTP has a distinctive pathology of arteriolar aneurysms with segmental intramural hyaline deposits. Published many decades ago, these classic papers antedate modern computerized literature searches, so this information has not been included in many modern reviews on TTP. We report 2 cases of TTP in pregnancy, both leading to fetal loss in the 2nd trimester. We noticed a distinctive pathology of TTP in the spiral arteries on the maternal surface of the placenta, particularly the "snowman sign," which differs somewhat from TTP in other organs due to the fact that TTP is superimposed on trophoblast-induced changes in these spiral arteries. In one of our cases, where the clinical diagnosis of TTP was difficult, the distinctive placental findings helped reinforce the clinical decision to perform potentially life-saving plasmapheresis.

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.

Thrombophilia and Placental Pathology

Thrombophilic states have been associated with a variety of adverse pregnancy outcomes. The underlying placental pathology linking thrombophilia to these outcomes closely resembles that seen in other pregnancy disorders associated with chronic obstruction of the maternal or fetal vasculature. No single placental lesion is pathognomonic for thrombophilia. However, the finding of typical pathologic lesions in the context of recurrent pregnancy loss, severe early onset disease, or neonatal coagulation abnormalities should prompt the consideration of an underlying thrombophilic state.

Perinatal stroke--risk factors and management

Stroke is an uncommon but increasingly recognised cause of mortality and long-term neurological morbidity in children. A significant number of these events appear to be caused by thromboembolic disease and, as with other childhood thrombotic problems, the incidence of central nervous system events appears highest during the neonatal period. In contrast to peripheral arterial and venous thrombotic problems, it is likely that a proportion of cerebral thromboembolic events occur either in utero or perinatally and reflect different risk factors from those occurring in older infants and children. The pathophysiology of perinatal stroke is complex and in many cases is likely to be multifactorial. It is now recognised that risk factors may relate to both maternal and placental problems as well as fetal and neonatal disorders. Large prospective studies of perinatal stroke are currently lacking and efforts to define the relative contribution from each of these areas are at an early stage. The complex nature of these disorders requires collaboration between a number of different disciplines including obstetrics, fetal medicine, pathology, neonatology and neurology. Of particular interest to haematologists is the possible impact of prothrombotic abnormalities in the pathophysiology of these events and also the potential for the use of antithrombotic agents in both management and prevention.

Prenatal stroke in a neonate heterozygous for factor V Leiden mutation

The authors report an infant with congenital hemiplegia associated to heterozygosity for factor V Leiden. Prenatal stroke in the left cerebral hemisphere was diagnosed by ultrasonography at the 28th week of pregnancy, and followed up until birth. Although neonatal neurologic examination was normal, a moderate right hemiparesis developed along the 1st months of life. Coagulation studies performed in the neonatal period and at the age of 18 months revealed activated protein C resistance due to factor V Leiden mutation (R506Q). There are some previous reports of stroke associated to this mutation in near or at term neonates, but to our knowledge this is the stroke detected at the most early stage of fetal development.

Severe fetal placental vascular lesions in term infants with neurologic impairment

OBJECTIVE

This study tests the hypothesis that placental disease can identify antepartum processes that either progress into the intrapartum period or predispose to intrapartum brain injury.

STUDY DESIGN

Lesions that affect large fetal vessels were compared in the placentas of 125 neurologically impaired term infants who were the focus of clinical negligence litigation and 250 consecutive singleton deliveries of >/=36 weeks of gestation.

RESULTS

One or more of 4 severe placental fetal vascular lesions (fetal thrombotic vasculopathy, chronic villitis with obliterative fetal vasculopathy, chorioamnionitis with severe fetal vasculitis, and meconium-associated fetal vascular necrosis) were found in 51% of index cases versus 10% of the comparison group ( P <.0001). Prevalence of these lesions in the 64 infants with cerebral palsy was 52% ( P <.0001).

CONCLUSION

Severe fetal placental vascular lesions are correlated highly with neurologic impairment and cerebral palsy. Their nature, duration, and anatomic location make them strong candidates for the antepartum processes that place fetuses at risk for brain injury during the intrapartum period.

Clinical and pathological umbilical cord abnormalities in fetal thrombotic vasculopathy

Although inherited fetal coagulation disorders may lead to fetal thrombotic vasculopathy (FTV) in occasional cases, several studies have failed to show a significant association between these 2 entities. This study tests the hypothesis that vascular stasis related to chronic umbilical cord obstruction might be a contributing factor. The study population consisted of 125 neurologically impaired term infants who were the focus of clinical negligence litigation. FTV, as defined by an average of >15 villi per slide exhibiting either a complete lack of blood vessels or villous stromal karyorrhexis, was found in the placentas of 23 cases. Clinical umbilical cord entanglement (ie, true knots or cord loops around the neck or body parts at delivery) was significantly more common in cases with FTV (61% vs 24% in cases without FTV; P = 0.0009). Potentially obstructive pathological abnormalities of the umbilical cord (marginal/ membranous insertion, decreased Wharton's jelly, maximum cord diameter <8 mm, or hypercoiling) were also more frequent in this group (30% vs 9% without FTV; P = 0.0055). Overall, 16 of 23 placentas with FTV had either clinical or pathological cord abnormalities. This study, with careful documentation of cord status at delivery and on the delivered placenta, is the first to report that clinical cord entanglement and pathological cord abnormalities are significantly increased in placentas with FTV.

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.

Thrombophilia and pregnancy complications

OBJECTIVE

This systematic review examines the strength of the association between thrombophilia and recurrent pregnancy loss and other serious obstetric complications. Study design Electronic databases and manual bibliography searches were used to identify studies evaluating the association between thrombophilia and pregnancy loss, preeclampsia, fetal growth retardation, and placental abruption.

RESULTS

Thrombophilic disorders are associated with an increased risk of fetal loss in the majority of case control and cohort studies. The risk is increased throughout pregnancy, but may be higher in the second and third trimester. The common pathologic finding of placental infarction suggests unexplained fetal loss may result from uteroplacental insufficiency and thrombosis. Thrombophilic disorders are not consistently associated with preeclampsia, fetal growth retardation, or placental abruption. Preliminary data suggest prophylactic anticoagulation may improve outcome in thrombophilic women with unexplained recurrent fetal loss.

CONCLUSION

Women with thrombophilia have an increased risk of pregnancy loss and possibly other serious obstetric complications, although definition of the magnitude of risk will require prospective longitudinal studies. Preliminary data suggesting prophylactic anticoagulation may improve gestational outcome provide a rationale for prospective randomized trials in thrombophilic women with unexplained recurrent fetal loss.

Thrombophilia and stillbirth: possible connection by intrauterine growth restriction

OBJECTIVE

To define the association between thrombophilia and unexplained stillbirth.

DESIGN

A case-control study.

SETTING

Obstetric department in a university affiliated hospital (Ha'Emek Medical Center, Afula).

POPULATION

A total of 53 women who delivered stillborns between March 1998 and June 2002 and 59 women with unremarkable obstetric history who delivered at the same period.

METHODS

Presence of genetic and acquired markers of thrombophilia was investigated.

MAIN OUTCOME MEASURE

Presence or absence of thrombophilia.

RESULTS

Thrombophilia was found in 34% of the women who delivered stillborns and in 20% of the 59 women with normal pregnancies (non-significant). However, significantly higher prevalence of thrombophilia (73%) was found in women who delivered small for gestational age stillborns compared with women who delivered normal birthweight stillborns (73%vs 18.4%, P < 0.0001).

CONCLUSIONS

There is no association between thrombophilia and stillbirth, overall. However, there is a clear association between thrombophilia and stillbirth of extremely growth restricted infants.

Placental pathology in fetal thrombophilia

The aim of this study was to test the hypothesis that placental vascular lesions of the fetal circulation are caused by fetal thrombophilic mutations. The study included 64 newborns of women with one or more of the following pregnancy complications: preeclampsia, placental abruption, and intrauterine growth restriction. The most prevalent inherited thrombophilias--factor V Leiden, factor II (prothrombin) G20210A, and homozygosity for methyltetrahydrofolate reductase C677T--were examined in maternal blood and fetal umbilical cord blood. One pathologist reviewed all of the slides for fetal vascular lesions. Associations between fetal thrombotic vasculopathy and fetal thrombophilia were tested for using Fisher's exact test; Z scores and gestational age were compared using the Student t-test. Fetal thrombophilic mutations were diagnosed in 19 of 64 newborns, 15 of whom had coexistent maternal thrombophilia. There was no statistical difference in the prevalence of thrombotic lesions of the fetal circulation between newborns with and without thrombophilia. The combination of maternal and fetal thrombophilia was also not associated with increased fetal vascular lesions. The results indicate that fetal thrombophilia alone, even in the context of maternal underperfusion, is not associated with fetal vascular lesions of the placenta, although it may represent an underlying risk factor for lesions triggered by other process(es).

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.

Haemostasis in normal and abnormal pregnancy

Haemostasis is a complex and dynamic equilibrium involving pro-coagulants, the natural anticoagulation system and fibrinolysis. Normal human pregnancy is associated with profound alterations to the process of haemostasis such that the pro-coagulant effect becomes dominant. There are very few studies which have attempted to elucidate the adaptations that take place in the uteroplacental circulation where the haemostatic system faces the conflicting tasks of maintaining blood fluidity during pregnancy while preparing for the haemostatic challenge of delivery. It is hypothesised that excessive thrombosis within the uteroplacental circulation provides the mechanistic basis for the reported associations between the inherited thrombophilias and major pregnancy complications. The evidence underpinning this widely quoted hypothesis is weak.

Is miscarriage a coagulopathy?

PURPOSE OF REVIEW

Pregnancy is a hypercoaguable state. The hypothesis has been developed that many cases of recurrent miscarriage and of later pregnancy complications are caused by a defective maternal haemostatic response leading to thrombosis of the uteroplacental vasculature and subsequent fetal loss. The evidence upon which this hypothesis is based is reviewed.

RECENT FINDINGS

The majority of studies report an increased prevalence of genetic thrombophilic mutations in the female partner of couples with recurrent miscarriage. It is important to note, however, that this is not a uniform finding. A sub-group of women with recurrent miscarriage has been demonstrated to be in a prothrombotic state before pregnancy, and that women in such a state are at an increased risk of miscarriage in future untreated pregnancies. Furthermore, the long-term health implications of this hypercoaguability have been highlighted in a large retrospective study reporting an increased risk of ischaemic heart disease among women with a history of pregnancy loss.

SUMMARY

Although recurrent miscarriage is a heterogeneous condition and no single abnormality will account for all cases of pregnancy loss, the relationship between abnormalities in the haemostatic pathways and pregnancy outcome is increasingly recognized. The challenges we face are how to discriminate between women with a thrombophilic defect who are destined to miscarry from those whose pregnancy will be successful, the pathology of pregnancy loss associated with thrombophilic defects, the role of the fetal genotype in determining pregnancy outcome, and the management of women with thrombophilic defects both during and beyond their reproductive years.