Placental lesions associated with cerebral palsy and neurologic impairment following term birth

Umbilical Cord Pathology

Problems and abnormalities of the umbilical cord play a significant role in perinatal morbidity and mortality. Because the umbilical cord is the lifeline of the fetus, any disruption of blood flow through the umbilical vessels can lead to severe fetal consequences.

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.

Ascending Infection: Acute Chorioamnionitis

Acute chorioamnionitis is a major cause of spontaneous preterm birth, accounting for more than 40% of deliveries complicated by preterm premature rupture of membranes or preterm labor. In the majority of cases, especially in preterm births, acute chorioamnionitis is caused by ascending polymicrobial infection. Recent evidence suggests that in some cases acute chorioamnionitis may have a noninfectious cause. In addition to the nonspecific patterns of conventional acute chorioamnionitis, this article describes characteristic inflammatory patterns indicative of a specific infectious cause. Several inflammatory entities of putative immunologic (noninfectious) etiology are addressed, including eosinophilic/T-cell vasculitis and chronic chorioamnionitis.

Morphologic changes in the placentas of HIV-positive women and their association with degree of immune suppression

OBJECTIVE

To provide baseline information regarding a possible association between specific histopathologic features of the placentas of HIV-positive women and the degree of immune suppression.

METHODS

A prospective single-blinded laboratory-based pilot study was conducted at Tygerberg Hospital, South Africa. The macroscopic and microscopic features of placentas from HIV-positive (n=91) and HIV-negative women (n=89) were compared and recorded using a standard template. Investigators were blinded to the participants' HIV status and CD4-positive cell count.

RESULTS

Placentas from the HIV-positive group were characterized by decreased weight and increased number of marginal infarcts relative to the HIV-negative group. The most important microscopic finding was the increased presence of villitis of unknown etiology (VUE) among the group of untreated HIV-positive women with CD4 cell counts of 200 cells/mm(3) or below.

CONCLUSION

Both macroscopic and microscopic differences relating to the degree of immune suppression were identified, which seemingly contradicts previous reports. Larger studies are warranted to define the function of antiretroviral therapy and VUE in the mechanism of mother-to-fetus transmission of HIV. Furthermore, the potential role of VUE in the pathophysiology of the compromised immune response observed among HIV-exposed but uninfected infants should be investigated.

Inflammation during fetal and neonatal life: implications for neurologic and neuropsychiatric disease in children and adults

Inflammation is increasingly recognized as being of both physiological and pathological importance in the immature brain. The rationale of this review is to present an update on this topic with focus on long-term consequences of inflammation during childhood and in adults. The immature brain can be exposed to inflammation in connection with viral or bacterial infection during pregnancy or as a result of sterile central nervous system (CNS) insults. Through efficient anti-inflammatory and reparative processes, inflammation may resolve without any harmful effects on the brain. Alternatively, inflammation contributes to injury or enhances CNS vulnerability. Acute inflammation can also be shifted to a chronic inflammatory state and/or adversely affect brain development. Hypothetically, microglia are the main immunocompetent cells in the immature CNS, and depending on the stimulus, molecular context, and timing, these cells will acquire various phenotypes, which will be critical regarding the CNS consequences of inflammation. Inflammation has long-term consequences and could speculatively modify the risk of a variety of neurological disorders, including cerebral palsy, autism spectrum disorders, schizophrenia, multiple sclerosis, cognitive impairment, and Parkinson disease. So far, the picture is incomplete, and data mostly experimental. Further studies are required to strengthen the associations in humans and to determine whether novel therapeutic interventions during the perinatal period can influence the occurrence of neurological disease later in life.

Inflammatory response in acute chorioamnionitis

Acute chorioamnionitis is the principal antecedent of premature birth and an important contributor to specific neonatal and other complications that may extend throughout subsequent life. A large number of studies have addressed surrogate markers of in-utero inflammation including cytokines, chemokines, pathogen-associated molecular patterns, and elicited host proteins. However, chorioamnionitis means inflammation occurring within the chorioamnion and the only practical direct measure available to assess this finding in most placentas is histopathology. The maternal and fetal inflammatory response to the presence of organisms within the placental membranes, so-called histologic chorioamnionitis, is the focus of this review. The issues addressed are the nature and origin of the eliciting antigen, mode of spread to the placenta, general characteristics of placental immunity, and a specific characterization of the spectrum of pathologic lesions observed in placentas with membrane infection.

Third-trimester stillbirths: correlative neuropathology and placental pathology

Although in recent years placental pathology has been the subject of a wealth of detailed descriptions and diagnostic categorization, systematic correlation of these conditions with the pathology of stillbirth has not been attempted. We examine the relationship between specific inflammatory, maternal, and fetal vascular pathologies and the central nervous system pathology and histological indicators of fetal compromise. Our design was a retrospective case series of 37 3rd-trimester intrauterine fetal deaths. In general, mixed placental pathologies were the rule, with three quarters of the placentas demonstrating combinations of maternal vascular pathology, fetal vascular pathologies, umbilical cord abnormalities, or inflammatory lesions. The range of brain pathology was limited to acute, severe congestion, white matter edema, and neuronal karyorrhexis (pontosubicular necrosis with or without neuronal karyorrhexis at other sites). Established periventricular leukomalacia was present in only 2 cases. The presence of neuronal karyorrhexis or white matter gliosis was correlated with the presence of a high-grade inflammatory lesion and with fetal thymic involution. Neuronal karyorrhexis, but not white matter gliosis, correlated as well with histologically established fetal vascular lesions in the placenta, even once the effect of inflammation was accounted for. Gliosis also correlated with inflammation, meconium staining, and thymic involution. Central nervous system injury may be the end result of complex placental pathologies, and neuronal injury may be a consequence of the fetal inflammatory response. The correspondence between the time courses of histological features of chorioamnionitis, neuronal karyorrhexis, and thymic involution points to irreversible central nervous system injury being common 12-48 hours prior to in utero demise.

Relationship between placental morphology and histological findings in an unselected population near term

Whilst individual histological features are well described, there are no universally agreed criteria as to what constitutes a clinically significant histological lesion of the placenta in an uncomplicated pregnancy, nor has the presence of such histological findings been systematically related to quantitative morphological characteristics of the placenta (such as placental shape, cord insertion and cord coiling). This study aims to explore this relationship and further to describe the incidence of predefined categories of histological lesions of the placenta in an unselected obstetric population recruited prior to delivery. The study is based upon the placental examination of 1,156 women with singleton pregnancies recruited prospectively in a single unit. Placentas were analysed where deliveries occurred between 34-43 weeks. The incidence of normal histological findings and specific histological categories, such as ascending genital tract infection, chronic placental underperfusion, intervillous thrombus and villitis of unknown aetiology, were noted. The relationship between placental morphological indices: coiling index, cord centrality index (distance of cord insertion on the chorionic plate from the centre) and eccentricity (shape of the placenta) and histological lesions was investigated. There were no significant differences between cord centrality and eccentricity between placentas with and without histological lesions except an association between hypercoiling of the umbilical cord and intervillous thrombosis and villitis of unknown aetiology (p = 0.024 and p = 0.009, respectively). The macroscopic morphological features of the placenta cannot predict the presence or absence of the histological placental lesions, nor are these lesions in general associated with differences in cord centrality, placental eccentricity or cord coiling.

Placental pathology is associated with illness severity in preterm infants in the first twenty-four hours after birth

BACKGROUND

Placental pathology is associated with long-term neurological morbidity. Little is known about the association of placental pathology and illness severity directly after birth in preterm infants.

OBJECTIVE

To determine the association between placental pathology and illness severity in preterm infants during the first 24 h after birth.

STUDY DESIGN

Placentas of 40 preterm infants, born after singleton pregnancies (gestational age 25.4-31.7 weeks, birth weight 560-2250 g) were assessed for histopathology. Illness severity was measured using the Score of Neonatal Acute Physiology Perinatal Extension (SNAPPE). A high SNAPPE reflects high illness severity.

RESULTS

Examination of the 40 placentas revealed: pathology consistent with maternal vascular underperfusion (MVU) (n=24), ascending intrauterine infection (AIUI) (n=17), villitis of unknown aetiology (VUE) (n=6), foetal thrombotic vasculopathy (FTV) (n=6), elevated nucleated red blood cells (NRBCs) (n=6), and chronic deciduitis (n=10). SNAPPE ranged from 1 to 53 (median 10). Infants with elevated NRBCs had a higher SNAPPE than infants without elevated NRBCs (median 30 vs. 10, p=0.014). The same was found for the presence of FTV (median 30 vs. 10, p=0.019). No relation existed between SNAPPE and the other placental pathologies.

CONCLUSIONS

Elevated NRBCs and FTV were associated with higher illness severity during the first 24 h after birth in preterm infants. Ascending intrauterine infection was not associated with high illness severity.

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.

Population case-control study of cerebral palsy: neonatal predictors for low-risk term singletons

OBJECTIVES

For singletons with cerebral palsy (CP) who were born at term, the goals were (1) to determine the proportion not admitted to a Special Care Unit/NICU (NICU), (2) to compare clinical descriptions of those admitted to NICUs and those not admitted, and (3) to identify neonatal predictors of CP among those not admitted to a NICU.

METHODS

A total-population case- (N = 442) control (N = 468) study of, singleton, term-born infants with CP, as ascertained from the Western Australian Cerebral Palsy Register, was performed.

RESULTS

All types of CP were represented among the 67% of term infants with CP (N = 295) who were not admitted to a NICU, which also included 54% of the subjects with the most severe impairments. Independent neonatal predictors were abnormalities of tone (odds ratio [OR]: 7.3 [95% confidence interval [CI]: 2-26.8]), temperature regulation (OR: 4.1 [95% CI: 1.2-14]), consciousness (OR: 3.7 [95% CI: 2-7]), and fontanelles (OR: 4.4 [95% CI: 0.8-23]), requirement for resuscitation (OR: 2.9 [95% CI: 2.2-12.9]), and birth defects (OR: 5.1 [95% CI: 2.4-10]). The risk of CP increased with the number of factors, but 58% of subjects who were not admitted to a NICU exhibited none of these factors.

CONCLUSIONS

Neonatal predictors of CP among term infants not admitted to a NICU were identified. However, 39% of all term singletons with CP were not admitted to a NICU and exhibited none of these predictors.

[Cerebral palsy and perinatal asphyxia (II--Medicolegal implications and prevention)]

Obstetric litigation is a growing problem in developed countries and its escalating cost together with increasing medical insurance premiums is a major concern for maternity service providers, leading to obstetric practice cessation by many practitioners. Fifty-four to 74 % of claims are based on cardiotocographic (CTG) abnormalities and their interpretation followed by inappropriate or delayed reactions. A critical analysis is performed about the nine criteria identified by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics in their task force on Neonatal Encephalopathy and Cerebral Palsy: four essential criteria defining neonatal asphyxia and five other suggesting an acute intrapartum event sufficient to cause cerebral palsy in term newborns. The importance of placental histologic examination is emphasized in order to confirm sudden catastrophic events occurring before or during labor or to detect occult thrombotic processes affecting the fetal circulation, patterns of decreased placenta reserve and adaptative responses to chronic hypoxia. It may also exclude intrapartum hypoxia by revealing some histologic patterns typical of acute chorioamnionitis and fetal inflammatory response or compatible with metabolic diseases. Magnetic resonance imaging (MRI) of the infant's damaged brain is very contributive to elucidate the mechanism and timing of asphyxia in conjunction with the clinical picture, by locating cerebral injuries predominantly in white or grey matter. Intrapartum asphyxia is sometimes preventable by delivering weak fetuses by cesarean sections before birth, by avoiding some "sentinel" events, and essentially by responding appropriately to CTG anomalies and performing an efficient neonatal resuscitation. During litigation procedures, it is necessary to have access to a readable CTG, a well-documented partogram, a complete analysis of umbilical cord gases, a placental pathology and an extensive clinical work-up of the newborn infant including cerebral MRI. Malpractice litigation in obstetric care can be reduced by permanent CTG education, respect of national CTG guidelines, use of adjuncts such as fetal blood sampling for pH or lactates, regular review of adverse events in Clinical Risk Management (CRM) groups and periodic audits about low arterial cord pH in newborns, admission to neonatal unit, the need for assisted ventilation and the decision-to-delivery interval for emergency operative deliveries. Considering the fast occurrence of fetal cerebral hypoxic injuries, and thus despite an adequate management, many intrapartum asphyxias will not be preventable. Conversely, well-documented hypoxic-ischemic brain insults during the antenatal period do not automatically exclude intrapartum suboptimal obstetric care.

Review: Fetal antigens--identity, origins, and influences on the maternal immune system

Pregnancy induces priming of the maternal cellular and humoral immune systems. The paternally-inherited fetal antigens that influence maternal T and B cells include both major and minor histocompatibility antigens - the same antigens that are problematic in allotransplantation. Animal models have facilitated our understanding of the lymphocyte responses to fetal antigens, and our appreciation of the parallel response in pregnant women is increasing. The physiologic properties of the placenta as well as trafficking of cells between mother and fetus allow ample opportunity for sampling of fetal proteins by the maternal immune system. Here, the current state of knowledge of fetal antigen-specific lymphocyte responses in pregnancy is reviewed.

Funisitis and chorionic vasculitis: relation to chorioamnionitis, timing and scoring

Five hundred consecutive cases with histologic chorioamnionitis and umbilical cord inflammation were analyzed to develop a staging system for funisitis and to correlate stage of funisitis with stage of chorioamnionitis in order to estimate the timing of various stages of funisitis. Funisitis progresses through venous involvement (with or without Wharton's jelly inflammation) to arterial involvement without Wharton's jelly and then full involvement of all three vessels and surrounding Wharton's jelly. Arterial involvement and full funisitis are strongly associated with stage III/IV chorioamnionitis, and imply a significant time interval following the onset of amniotic cavity inflammation.

Incidence and clinicopathologic correlation of fetal vessel thrombosis in mono- and dichorionic twin placentas

OBJECTIVE

To determine the incidence of fetal vessel thrombosis in monochorionic-diamniotic and dichorionic-diamniotic twin placentas, and its association with intrauterine growth retardation (IUGR), hypertensive disorders of pregnancy, twin-twin transfusion syndrome (TTTS), fetal vascular anastomoses, chorangiosis, and chorioamnionitis.

STUDY DESIGN

Histologic slides from 80 pairs of monochorionic and 80 pairs of dichorionic twin placentas were reviewed for evidence of fetal vessel thrombosis (≥5 adjacent avascular terminal villi with upstream intravascular fibrin thrombi). Associations with clinical and other pathologic variables were analyzed by χ(2) tests.

RESULT

Thrombosis occurred in 7.5% of monochorionic and 3.1% of dichorionic twin placentas (P=0.090). It was associated with IUGR among the monochorionic twins (P=<0.0001) and with hypertensive disorders of pregnancy among the dichorionic twins (P=0.018). Vascular anastomoses, TTTS, chorangiosis, and chorioamnionitis were not associated with fetal vessel thrombosis.

CONCLUSION

Fetal vessel thrombosis was identified more frequently in monochorionic twins, but this difference was not statistically significant. It is associated with IUGR in monochorionic twins, but not with TTTS or fetal vascular anastomoses at the chorionic surface.

Predictors of outcome at 2 years of age after early intrauterine growth restriction

OBJECTIVE

To examine the relative importance of antenatal and perinatal variables on short- and long-term outcome of preterm growth restricted fetuses with umbilical artery (UA) Doppler abnormalities.

METHODS

This was a cohort study of 180 neonates with birth weight < 10(th) percentile, gestational age at delivery < 34 weeks and abnormal Doppler ultrasound examination of the UA. Various antenatal and perinatal variables were studied in relation to short- and long-term outcome.

RESULTS

Neonatal and overall mortality (up to 2 years of age) were predicted by low gestational age at delivery. Neonatal mortality was additionally predicted by absent or reversed UA end-diastolic flow, while the presence of severe neonatal complications and placental villitis were additional predictors of both infant (between 28 days and 1 year of postnatal life) and overall mortality. Placental villitis was found to be the only predictor of necrotizing enterocolitis. Low gestational age at delivery, male sex, abnormal cardiotocography, absent or reversed UA end-diastolic flow and the HELLP syndrome predicted respiratory distress syndrome. Abnormal neurodevelopmental outcome at 2 years was predicted by low birth weight (< 2.3(rd) percentile), fetal acidosis (UA pH < 7.00), and placental villitis.

CONCLUSION

Less advanced gestation at delivery remains an important predictor of short-term outcome in growth-restricted fetuses. In addition, the presence of placental villitis may aid neonatologists in the early identification of infants at increased risk of necrotizing enterocolitis, death and abnormal neurodevelopment at 2 years of age. Abnormal neurodevelopment was related to low weight and acidosis at birth, indicating that the severity of malnutrition and fetal acidosis affect long-term outcome.

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.

Histologic chorioamnionitis and acute neurologic impairment in premature infants

OBJECTIVE

To determine if histologic chorioamnionitis is associated with acute neurologic impairment as evaluated by auditory brainstem response in premature infants.

METHODS

A prospective study was performed to compare auditory neural function at birth between premature infants with maternal histologic chorioamnionitis and infants without maternal histologic chorioamnionitis. Our inclusion criteria was 28-33 weeks gestational age (GA) infants who had maternal placental histopathology performed. Infants with toxoplasmosis, other infections, rubella, cytomegalovirus and herpes simplex (TORCH) infections, chromosomal disorders, cranio-facial anomalies and/or unstable condition were excluded. Bilateral monaural auditory brainstem evoked responses were performed using 80 dB nHL click stimuli at a repetition rate of 29.9/s within 48 h after birth.

RESULTS

Of 101 infants who met study criteria, 29 infants were born with history of maternal histologic chorioamnionitis. There were no significant differences between infants with histologic chorioamnionitis and infants without histologic chorioamnionitis in perinatal factors except for GA, pregnancy induced hypertension, and exposure to antenatal magnesium sulphate. After controlling for confounders, histologic chorioamnionitis was not associated with prolonged absolute wave latencies I, III, and V and/or decreased frequency of mature auditory waveform compared to infants without histologic chorioamnionitis.

CONCLUSION

Histologic chorioamnionitis is not associated with neurologic impairment at birth in premature infants.

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.

Ischemic perinatal stroke secondary to chorioamnionitis: a histopathological case presentation

Ischemic perinatal stroke is a serious potential complication of delivery. In utero infection may be responsible for an underestimated proportion of perinatal stroke. Limited literature identifies objective evidence of ischemic perinatal stroke as a consequence of uterine infection. The authors report a neonate with ischemic stroke and documented findings of severe chorioamnionitis with umbilical vein thrombosis. A term neonate, after uneventful pregnancy and delivery, presented on the third day of life with seizures. Investigations for metabolic, electrolyte, infectious, and hypercoaguability derangements were normal. Extensive acute infarction in the left middle cerebral artery territory was diagnosed by magnetic resonance imaging (MRI). Placental histopathology confirmed the presence of chorioamnionitis. On follow-up assessments, mild residual neurologic deficits have persisted. Chorioamnionitis has been correlated with ischemic perinatal stroke. In addition to the recognized inflammatory cascade of in utero infection, umbilical vein thrombosis with subsequent ''paradoxical'' embolization may represent one mechanism responsible for this association.

Disorders of placental circulation and the fetal brain

Disorders of the placental circulation, including the release of deleterious mediators to the fetus, are important risk factors for central nervous system complications. These disorders result in discrete patterns of placental injury detectable by a thorough placental pathologic examination. Consideration of the location, severity, multiplicity, and timing of these lesions is critical to a full understanding of their significance. Less than 10% of placentas from term infants that later develop cerebral palsy lack any evidence of placental abnormalities potentially related to adverse outcome.

Cerebral palsy in term infants: a clinicopathologic analysis of 158 medicolegal case reviews

Our understanding of cerebral palsy (CP) in term infants is hindered by its low incidence and sporadic presentation. Many of these CP cases enter litigation, and a focused review of medicolegal consultations provides an opportunity to better understand the pathogenesis of these cases. In this study complete clinical and pathologic data from 158 cases of CP complicating singleton pregnancies after 36 weeks of gestation were prospectively collected over a 10-year period extending from 1998 to 2008. A hierarchical system was used to separate cases into the following 5 groups: (1) clinical/sentinel events (20%), (2) severe large fetoplacental vascular lesions (34%), (3) placental lesions indicative of chronic placental dysfunction (23%), and (4) placental lesions indicative of subacute/chronic adaptation to hypoxia (15%). The remaining 8% (group 5) of cases were idiopathic. Common to all subgroups was clinical and/or pathologic evidence of umbilical cord obstruction, which was observed in 63% of cases. The following clinical features significantly differed among subgroups. Group 1 had less maternal obesity and more cases involving multicystic encephalopathy. Group 2 had increased oligohydramnios, cerebral edema, nucleated red blood cell counts greater than 10 000/mm(3), hypoglycemia, pulmonary hypertension, and cardiac dysfunction. Group 3 had more preeclampsia and, together with group 2, more infants with a low ponderal index. Group 5 had a higher prevalence of positive family history of neurodevelopmental disorders. In conclusion, infant cases subject to litigation related to CP following term birth can be separated into distinct clinicopathologic subgroups with only a small number lacking either clinical/sentinel events or placental evidence of subacute or chronic in utero stress.

Elevated circulating fetal nucleated red blood cells and placental pathology in term infants who develop cerebral palsy

An elevated circulating fetal nucleated red blood cell count has long been recognized as an indicator of significant intrauterine stress. However, the nature of the causative events and their timing remain controversial. In this study, subacute and chronic placental lesions known to be associated with neurodisability were used as surrogates for antenatal stress. Mother-infant pairs with complete blood counts within 2 hours of delivery (n = 81) were drawn from a larger database of 152 term infants with cerebral palsy. An elevated nucleated red blood cell count (2.5 x 10(3)/mm(3)) in these infants was associated with a significantly increased prevalence of subacute or chronic placental lesions, whereas clinical findings did not significantly differ. The number of nucleated red blood cells per 10 high-power fields of villous parenchyma was directly correlated with the nucleated red blood cell count, and a threshold of 10 or more nucleated red blood cells predicted a nucleated red blood cell count greater than 2.5 x 10(3)/mm(3). Among individual placental lesions, multiple foci of avascular villi and chronic villitis were significantly associated with an elevated nucleated red blood cell count, whereas meconium-associated vascular necrosis showed a borderline association. Acute chorioamnionitis was the only placental lesion more common in the group without elevated nucleated red blood cell count. The presence of significant placental lesions was associated with an elevated nucleated red blood cell count in infants with or without either acidosis (cord pH <7.0) or birth asphyxia (American College of Obstetrics and Gynecology criteria). Acidosis and birth asphyxia were not significantly related to an elevated nucleated red blood cell count in infants without these placental lesions.

Infection and fetal neurologic injury

PURPOSE OF REVIEW

Antepartum fetal exposure to infection/inflammation is a more important risk factor for brain injury than intrapartum hypoxia in both the term and preterm neonate. Such preexisting infection/inflammation might also provide the platform for subsequent intrapartum hypoxic-ischaemic damage. This review will discuss the complex interaction between fetal inflammatory response and neurotoxicity, and focus on the clinical implications of the synergistic interaction between infection/inflammation and hypoxia-ischaemia.

RECENT FINDINGS

Current evidence indicates that inflammatory mediators are directly neurotoxic, and also sensitize the fetal brain tissue to a greater magnitude of damage by subsequent hypoxia-ischaemia by lowering the threshold at which hypoxia initiates neuronal cell apoptosis/cell death.

SUMMARY

Further studies are urgently needed to characterize the fetuses at risk of damage, the duration of exposure required to cause injury, the influence of gestational age and whether Caesarean section may be protective. Until then clinicians should maintain a high level of surveillance in labours complicated by infection and avoid additional exposure to hypoxic-ischaemic insults.

Does placental inflammation relate to brain lesions and volume in preterm infants?

OBJECTIVES

To evaluate the association between histologic inflammation of placenta and brain findings in ultrasound examinations and regional brain volumes in magnetic resonance imaging in very-low-birth-weight (VLBW) or in very preterm infants.

STUDY DESIGN

VLBW or very preterm infants (n = 121) were categorized into 3 groups according to the most pathologic brain finding on ultrasound examinations until term. The brain magnetic resonance imaging performed at term was analyzed for regional brain volumes. The placentas were analyzed for histologic inflammatory findings.

RESULTS

Histologic chorioamnionitis on the fetal side correlated to brain lesions in univariate but not in multivariate analyses. Low gestational age was the only significant risk factor for brain lesions in multivariate analysis (P < .0001). Histologic chorioamnionitis was not associated with brain volumes in multivariate analyses. Female sex, low gestational age, and low birth weight z score correlated to smaller volumes in total brain tissue (P = .001, P = .0002, P < .0001, respectively) and cerebellum (P = .047, P = .003, P = .001, respectively). In addition, low gestational age and low-birth-weight z score correlated to a smaller combined volume of basal ganglia and thalami (P = .0002).

CONCLUSIONS

Placental inflammation does not appear to correlate to brain lesions or smaller regional brain volumes in VLBW or in very preterm infants at term age.

Involvement of Hofbauer cells and maternal T cells in villitis of unknown aetiology

AIMS

The nature of villitis of unknown aetiology (VUE) is intriguing in terms of its aetiology, origin of inflammatory cells and immunophenotype of T cells involved. The aim was to determine the origin of macrophages and the immunophenotype of T lymphocytes in VUE associated with various complications of pregnancy.

METHODS AND RESULTS

Placentas with VUE (n = 45) were studied by chromogenic in-situ hybridization (CISH) for Y chromosome (DYZ1) and immunohistochemistry for CD14, CD68, Ki67 (n = 10; all from male neonates) and a panel of T-cell antigens (CD3, CD4 and CD8) (n = 35). All of the placentas from male neonates showed CISH+ signals from Y chromosomes in the majority of macrophages, but not in lymphocytes, indicating that the macrophages were of fetal origin. Many macrophages of the affected chorionic villi were Ki67+, suggesting that they are hyperplastic Hofbauer cells. Among the lymphocytes, CD8+ T cells outnumbered CD4+ T cells in all placentas with different obstetrical conditions.

CONCLUSIONS

We define primary components of VUE as maternal CD8+ T cells and hyperplastic Hofbauer cells. We propose that VUE is a unique inflammatory reaction where the leucocytes from two hosts are key partners, analogous to either allograft rejection or graft-versus-host disease.

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.

Chronic villitis of unknown etiology

The diagnosis of chronic villitis of unknown etiology (CVUE), characterized by focal areas of inflammation with mononuclear cells and areas of fibrinoid necrosis in chorionic villi, can only be set-up after exclusion of a latent maternal-fetal transmission of infectious agents by sophisticated techniques such as polymerase chain reaction. Significant associations of CVUE with maternal body mass index, multigravidity and ethnicity were reported. While a fetal origin of the inflammatory cells has been evoked, there are many more arguments drawn from histopathology and immunohistology for a maternal immune response against the foreign fetal allograft. CVUE is detected in 7-33% of placentas, mainly after idiopathic intrauterine growth retardation, unexplained prematurity, preeclampsia, perinatal asphyxia and intrauterine fetal death. CVUE is also more frequent in pregnancies affected by autoimmune or alloimmune diseases. Considering the high rate of recurrences after an index case of CVUE, we would suggest to associate aspirine and corticosteroids in further pregnancies, a regimen that was successful in our experience but must be confirmed by other studies. The same is true for the alleviated inflammatory immunologic response recently obtained by a weekly use of maternal intravenous immunoglobulins.

Villitis of unknown etiology: noninfectious chronic villitis in the placenta

Villitis of unknown etiology (VUE) is an important pattern of placental injury occurring predominantly in term placentas. Although overlapping with infectious villitis, its clinical and histologic characteristics are distinct. It is a common lesion, affecting 5% to 15% of all placentas. When low-grade lesions affecting less than 10 villi per focus are excluded, VUE is an important cause of intrauterine growth restriction and recurrent reproductive loss. Involvement of large fetal vessels in the placenta (obliterative fetal vasculopathy) in cases of VUE is a strong risk factor for neonatal encephalopathy and cerebral palsy. Although the etiology of the eliciting antigen is unknown, many other characteristics of the immune response have been clarified. VUE is caused by maternal T lymphocytes, predominantly CD8-positive, that inappropriately gain access to the villous stroma. Fetal antigen-presenting cells (Hofbauer cells) expand and are induced to express class II major histocompatibility complex molecules. Maternal monocyte-macrophages in the perivillous space likely amplify the immune response. Although much speculation exists that VUE represents a host-versus-graft reaction analogous to transplant rejection, other eliciting antigens have not been excluded. Irrespective of target antigen or antigens, the pathophysiologic implications of having activated maternal lymphocytes within vascularized fetal tissues are not trivial.

The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network Beneficial Effects of Antenatal Repeated Steroids study: impact of repeated doses of antenatal corticosteroids on placental growth and histologic findings

OBJECTIVE

In utero exposure to repeated doses of antenatal corticosteroids (ACSs) has been shown to reduce fetal growth. Our goal was to evaluate whether weekly betamethasone (R-ACS) alters placental growth and histologic findings.

STUDY DESIGN

In a multicenter randomized controlled trial of R-ACS vs a single course of ACS followed by weekly placebo (S-ACS), placentas were weighed after removal of the membranes and umbilical cord. A single pathologist who was masked to study group and pregnancy outcomes performed histologic evaluation for placental calcifications, infarction, fibrin deposition, and hemorrhage or thrombus formation, acute and chronic chorioamnionitis, fibromuscular vascular hyperplasia, nucleated red blood cells, and villous crowding, edema, fibrosis, or fibrinoid necrosis. Findings were compared between study groups and according to the number of courses of ACS.

RESULTS

One hundred ninety-four placentas were available for evaluation. Univariable analyses revealed no differences between study groups in any of the 19 evaluated histologic parameters between R-ACS and S-ACS groups overall or in analyses that were restricted to deliveries at < 32 or > or = 32 weeks of gestation. Calcifications were more common (P = .045) in the R-ACS group after controlling for other factors. Multivariable analysis revealed increasing gestational age at delivery, but not increasing ACS courses, to be associated with decreasing chorionic inflammation, villous edema, and fibrosis and with increasing villus crowding, fibrin deposition, and calcifications. Ninety-three placentas were weighed before formalin fixation. After controlling for delivery gestation and infant gender, placental weight was significantly lower in the R-ACS group (P = .017) and was related inversely to the number of ACS courses (P = .037). This finding was confirmed only for deliveries at > or = 32 weeks of gestation (525 vs 441 g for R-ACS and S-ACS group, respectively; P = .036).

CONCLUSION

Repeated antenatal corticosteroid treatments in pregnancy are associated with decreased placental growth in a dose-dependent fashion, but not with evident differences in histologic markers of placental inflammation, ischemia, or infarction. Histologic placental abnormalities should not be attributed to repeated courses of corticosteroids.

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 lesions as predictors of cerebral palsy and abnormal neurocognitive function at school age in extremely low birth weight infants (<1 kg)

Extremely low birth weight (ELBW) infants (<1 kg) have high rates of neurodisability. Although previous studies have implicated placental lesions in adverse short-term neurologic outcomes in this population, none have assessed their effects in these children once they reach school age. We conducted a secondary analysis of placental pathology in a cohort study of inborn singleton ELBW infants born between 1992 and 1995 and evaluated for cerebral palsy (CP) and abnormal neurocognitive testing at 8 years of age (N = 129). The neurocognitive tests were the Kaufman Assessment Battery for Children (K-ABC) and 6 subtests of the NEPSY: A Developmental Neuropsychological Assessment. We found that placental lesions associated with maternal vascular underperfusion (increased syncytial knots and acute atherosis) were risk factors for CP, while villous edema was associated with low scores on both neurocognitive tests. Histologic chorioamnionitis (HCA) was not predictive of outcome in the population as a whole, but a severe fetal vascular response was associated with a lower NEPSY score in the subpopulation with HCA (N = 69). Placentas with increased syncytial knots, villous edema, and those with neither finding constituted nonoverlapping subgroups with distinct pathologic and perinatal characteristics. Among infants with villous edema (N = 25), those with neurologic impairment had lower gestational ages and more severe degrees of HCA. However, by logistic regression these other factors were not independent risk factors for abnormal neurocognitive testing, and only HCA with a severe fetal vascular response decreased the association of villous edema with low test scores for NEPSY, but not K-ABC.

Antenatal infection/inflammation and fetal tissue injury

There is a clear association between antenatal infection/inflammation and preterm labour, with intrauterine infection complicating up to one third of preterm deliveries. In addition to this, there is now accumulating evidence that intrauterine infection and inflammation can lead to the development of a systemic inflammatory response in the fetus and subsequent tissue injury. The fetal inflammatory response is characterized by funisitis, high levels of pro-inflammatory cytokines in the amniotic fluid and cord blood, and systemic immune activation. This review discusses the evidence for this process and focuses on the clinical and experimental data supporting the hypothesis that these inflammatory processes contribute to brain and lung injury in the newborn.

The role of perinatal pathological examination in subclinical infection in obstetrics

Infectious agents are associated with a wide range of obstetric complications and pathological processes affecting the placenta, membranes and fetus. In some cases there will be associated maternal symptoms and signs indicating an infectious aetiology, but in the majority such infection is subclinical, and specific diagnosis or confirmation is achieved following pathological examination of the delivered placenta and/or fetus. There are two major groups of microorganism-related mechanisms associated with significant perinatal morbidity and mortality. First, ascending genital-tract infection, almost always bacterial, which ranges from localized choriodecidual inflammation to frank chorioamnionitis with fetal sepsis; this is a major cause of mid-trimester miscarriage and severe preterm delivery, and more recent data suggest that it may also have potentially important effects via cytokine release mediating neonatal cerebral injury. Second, haematogenous spread of maternal systemic infection--bacterial, viral or parasitic--which may result in isolated placental effects or transmission to the fetus with associated developmental abnormalities and neonatal complications. In many cases distinctive histopathological findings are described, and in addition a wide range of techniques is now available for culture and microscopy to confirm these diagnoses; such techniques include highly specific immunohistochemical markers and sensitive molecular diagnostic techniques such as the polymerase chain reaction. It is likely that with increasingly widespread availability of these investigative approaches to obstetric pathology, a greater understanding of the role of infectious agents in obstetric complications will become apparent.

Infections and other inflammatory conditions

The etiology of cerebral palsy and other related perinatal brain injuries is poorly understood. Infections of the central nervous system are rare but important causes of neurodisability. Recent evidence suggests that infections and other inflammatory conditions apparently limited to the placenta are also associated with an increased risk of neurologic impairment. A major hypothesis to explain this connection is that cytokines, activated inflammatory cells, and other mediators of the innate immune response are released into the fetal circulation where they can directly or indirectly affect the development or integrity of the central nervous system. This review surveys the organisms, mediators, and placental lesions that have been associated with perinatal brain injury.

The neuropathology of acquired pre- and perinatal brain injuries

Acquired pre- and perinatal brain injuries comprise a significant proportion of perinatal neuropathology. They are associated with placental abnormalities, maternal factors, multiple gestations, and preterm labor, as well as with the later development of cerebral palsy and developmental delay. The patterns of perinatal brain injury depend on the etiology (often hypoxic-ischemic) and the timing relative to the development of the fetal nervous system, since the vulnerabilities of gray and white matter differ across postconceptional age and by neuroanatomic site. Nevertheless, characteristic features allow determination of the approximate age and cause of each pattern of injury in the perinatal brain.

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.

Introduction: the importance of timely and complete placental and autopsy reports

Poor communication, delayed communication, and failure to identify or evaluate significant placental lesions are major causes of failure to explain the cause of severe injuries in newborns. Families coping with stillbirth or a child with cerebral palsy need to have a sense that their bereavement deserves and is receiving major attention, and that a determined effort to explain the cause is being made and will be presented in a timely fashion. They are coping with long-lasting and devastating financial and emotional burdens. The obstetrician, neonatologist, and pathologist who have accepted the role of physician to these patients have a duty to cooperate as fully as they can to make those burdens as bearable as possible.

Placental Pathology and Clinical Outcomes in a Cohort of Infants Admitted to a Neonatal Intensive Care Unit

BACKGROUND

Placental pathology predicts persistent neurological impairment, even in normally grown infants. However, few studies have linked placental pathology with neonatal outcomes in a large population.

METHODS

We matched the clinical outcomes of a cohort of neonates admitted to a neonatal intensive care unit (NICU) with placental pathology, where available, and examined (by multivariable logistic regression) the relationship between placental pathologies and these outcomes. The outcomes included neonatal death, necrotizing enterocolitis, and intraventricular hemorrhage > or = grade 3. A forward selection model (10% significance level for entry) was used after adjusting for onfounding factors.

RESULTS

A detailed gross and microscopic pathological report was available for 1296 eligible infants (64%). Specific placental features were associated with specific neonatal outcomes. The Canadian Neonatal Network has previously determined that specific changes in the pattern of neonatal care can alter the incidence and severity of these outcomes. In the placentas from pregnancies delivering small for gestational age infants who were subsequently admitted to NICU, two different patterns of placental pathologies were found, one ischemic and the other inflammatory.

CONCLUSION

Frozen section examination of placentas may facilitate more timely delivery of tailored neonatal therapy.

Value of placental microbial evaluation in diagnosing intra-amniotic infection

OBJECTIVE

To evaluate the ability of microbiologic and pathologic examination of the placenta to accurately diagnose intraamniotic infection and inflammation.

METHODS

One hundred eighty-three women with a clinically indicated amniocentesis were enrolled prospectively. We applied our analysis to 56 women with evidence of preterm labor or preterm premature rupture of membranes who delivered within 48 hours of amniotic fluid testing results. Twenty-three patients, assessed for fetal lung maturity in the third trimester, served as controls. Amniotic fluid was cultured for aerobic, anaerobic, Ureaplasma, and Mycoplasma species. We used mass spectrometry to assess the degree of intraamniotic inflammation (Mass Restricted scoring). After delivery, microbiologic and histologic studies of the placenta were performed. These results were interpreted in comparison with the direct microbiologic and inflammatory analysis of the amniotic fluid. A sample size of 45 patients was required to show a test accuracy of 80% or more.

RESULTS

Ninety-two percent of women with positive amniotic fluid cultures tested with at least one positive placenta culture. Eighty percent of women who had negative amniotic fluid cultures also tested with a positive placenta culture. The accuracy of placental cultures in predicting amniotic fluid infection varied from 44% to 57%. Placental pathology showed an accuracy of only 58% in diagnosing intraamniotic inflammation.

CONCLUSION

Placental microbiologic and histologic studies poorly reflect the infectious and inflammatory status of the amniotic fluid. Results of such studies should be interpreted with caution in the management and future counseling of women with preterm labor or preterm premature rupture of membranes.

LEVEL OF EVIDENCE

II.

Cord abnormalities, structural lesions, and cord “accidents”

As the umbilical cord is the lifeline of the fetus, obstruction or disruption of blood flow through the umbilical vessels can lead to severe fetal compromise. Obstruction is usually mechanical in nature and is associated with compression of the umbilical cord and umbilical vessels. Disruption of umbilical or fetal vessels is usually traumatic in origin. These conditions have in common a loss of blood flow to the fetus and an association with adverse perinatal outcome.