Cerebral palsy and thrombi in placental vessels of the fetus: insights from litigation

Placental pathology is necessary to understand common pregnancy complications and achieve an improved taxonomy of obstetrical disease

The importance of a fully functioning placenta for a good pregnancy outcome is unquestioned. Loss of function can lead to pregnancy complications and is often detected by a thorough placental pathologic examination. Placental pathology has advanced the science and practice of obstetrics and neonatal-perinatal medicine by classifying diseases according to underlying biology and specific patterns of injury. Many past obstacles have limited the incorporation of placental findings into both clinical studies and day-to-day practice. Limitations have included variability in the nomenclature used to describe placental lesions, a shortage of perinatal pathologists fully competent to analyze placental specimens, and a troubling lack of understanding of placental diagnoses by clinicians. However, the potential use of placental pathology for phenotypic classification, improved understanding of the biology of adverse pregnancy outcomes, the development of treatment and prevention, and patient counseling has never been greater. This review, written partly in response to a recent critique published in a major obstetrics-gynecology journal, reexamines the role of placental pathology by reviewing current concepts of biology; explaining the most recent terminology; emphasizing the usefulness of specific diagnoses for obstetrician-gynecologists, neonatologists, and patients; previewing upcoming changes in recommendations for placental submission; and suggesting future improvements. These improvements should include further consideration of overall healthcare costs, cost-effectiveness, the clinical value added of placental assessment, improvements in placental pathology education and practice, and leveraging of placental pathology to identify new biomarkers of disease and evaluate novel therapies tailored to specific clinicopathologic phenotypes of both women and infants.

Neonatal stroke: Clinical characteristics and neurodevelopmental outcomes

BACKGROUND

Neonatal stroke can potentially result in significant neurological sequelae in affected infants. Studies on neurodevelopmental outcomes and the need for rehabilitation therapies in the first two years are limited. We aimed to describe the clinical characteristics, diagnostic evaluation, and neurodevelopmental outcomes of a cohort of infants with neonatal stroke.

METHODS

A retrospective cohort study of infants with neonatal stroke, from 2011 to 2020. Maternal and infant characteristics were described. Placental pathology, echocardiogram results, and prothrombotic evaluations were reported. The neurodevelopmental outcomes using Bayley scale of infant development (BSID III), rates of epilepsy and cerebral palsy, and the need for rehabilitation therapies at two years were described.

RESULTS

During the study period, 55 infants had neonatal stroke. Majority (93%) were term or late preterm infants. Maternal chorioamnionitis and perinatal HIE were diagnosed in about a third of the infants. Most (66%) of the infants presented with seizures. On brain MRI, the lesions were unilateral in 76% and arterial in origin in 86% of the infants. Meconium exposure (42%), intrauterine inflammation/infection (37%) and fetal vascular malperfusion (16%) were seen on placental histopathology. At two-year BSID III assessment, median (min, max) composite cognitive, language, and motor scores were 100 (55-145), 97 (47-124), and 100 (46-141), respectively. Among this cohort, epilepsy (27%), cerebral palsy (16%) and the need for rehabilitation therapies (physical -24%, occupational -18%, speech -21%) were reported at two years.

CONCLUSION

Neonatal stroke presented commonly in term or late preterm infants with seizures. It was unilateral and arterial in origin in most infants. Maternal chorioamnionitis and perinatal HIE were the most commonly associated conditions at birth. About one-fifth of the infants had mild or severe developmental delays at two years. Epilepsy, cerebral palsy, and need for rehabilitation therapies were noted in a significant proportion of infants at two years.

Sildenafil-Mediated Neuroprotection from Adult to Neonatal Brain Injury: Evidence, Mechanisms, and Future Translation

Cerebral stroke, traumatic brain injury, and hypoxic ischemic encephalopathy are among the most frequently occurring brain injuries. A complex pathogenesis, characterized by a synergistic interaction between alterations of the cerebrovascular system, cell death, and inflammation, is at the basis of the brain damage that leads to behavioral and neurodevelopmental disabilities in affected subjects. Sildenafil is a selective inhibitor of the enzyme phosphodiesterase 5 (PDE5) that is able to cross the blood-brain barrier. Preclinical data suggest that sildenafil may be a good candidate for the prevention or repair of brain injury in both adults and neonates. The aim of this review is to summarize the evidence supporting the neuroprotective action of sildenafil and discuss the possible benefits of the association of sildenafil with current therapeutic strategies.

Placental malperfusion in response to intrauterine inflammation and its connection to fetal sequelae

Exposure to intrauterine inflammation (IUI) is associated with short- and long-term adverse perinatal outcomes. However, little data exist on utilizing placenta to prognosticate fetal injury in this scenario. Our study aimed to utilize imaging modalities to evaluate mechanisms contributing to placental injury following IUI exposure and correlated it to concomitant fetal brain injury. CD1 pregnant dams underwent laparotomies and received intrauterine injections of either lipopolysaccharide (LPS; a model of IUI) or phosphate-buffered saline (PBS). In utero ultrasound Doppler velocimetry of uterine and umbilical arteries and magnetic resonance imaging (MRI) of placental volumes with confirmatory immunohistochemical (vimentin) and histochemistry (fibrin) analyses were performed. ELISA for thrombosis markers, fibrinogen and fibrin was performed to analyze thrombi in placenta. Fetal brain immunohistochemistry was performed to detect microglial activation (ionized calcium-binding adaptor molecule 1, Iba1). On ultrasound, LPS group demonstrated elevated resistance indices, pulsatility indices and a greater occurrence of absent end-diastolic flow in the umbilical and uterine arteries. In the fetus, there was an increased cardiac Tei indices in the LPS group. MRI revealed decreased volume of placenta in the LPS group associated with placental thinning and placental endothelial damage on immunohistochemistry. Decreased fibrinogen content and more thrombi staining in placenta exposed to maternal LPS indicated the hypercoagulability. Furthermore, the expression of Iba1was significantly associated with placental thickness (r = -0.7890, Pearson correlation coefficient). Our data indicate that IUI can trigger events leading to maternal placental malperfusion and fetal vessel resistance, as well as predispose the developing fetus to cardiac dysfunction and brain damage. Furthermore, our data suggest that prenatal ultrasound can be a real-time clinical tool for assessing fetal risk for adverse neurologic outcomes following the potential IUI exposure.

Placental Pathology in Neonatal Stroke: A Retrospective Case-Control Study

OBJECTIVE

To assess the association of placental abnormalities with neonatal stroke.

STUDY DESIGN

This retrospective case-control study at 3 academic medical centers examined placental specimens for 46 children with neonatal arterial or venous ischemic stroke and 99 control children without stroke, using a standard protocol. Between-group comparisons used χ² and Fisher exact t test. Correlations used Spearman correlation coefficient.

RESULTS

Case placentas were more likely than controls to meet criteria for ≥1 of 5 major categories of pathologic abnormality (89% vs 62%; OR, 5.1; 95% CI, 1.9-14.0; P = .0007) and for ≥2 categories (38% vs 8%; OR, 7.3; 95% CI, 2.9-19.0; P < .0001). Fetal vascular malperfusion occurred in 50% of cases and 17% of controls (OR, 4.8; 95% CI, 2.2-10.5; P = .0001). Amniotic fluid inflammation occurred in 46% of cases with arterial ischemic stroke vs 25% of controls (OR, 2.6; 95% CI, 1.1-6.1; P = .037). There was evidence of a "stress response" (meconium plus elevated nucleated red blood cells) in 24% of cases compared with 1% of controls (OR, 31; 95% CI, 3.8-247.0; P < .0001).

CONCLUSIONS

Placental abnormality was more common in children with neonatal stroke compared with controls. All placental findings represent subacute-to-chronic intrauterine stressors. Placental thrombotic processes were associated with both arterial and venous stroke. Our findings provide evidence for specific mechanisms that may predispose to acute perinatal stroke. Amniotic fluid inflammation associated with neonatal arterial ischemic stroke deserves further investigation.

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.

Perinatal thrombosis: implications for mothers and neonates

Stroke is more likely to occur in the perinatal period than any other time in childhood, and these events can lead to a lifetime of intellectual and motor disabilities, epilepsy, and behavioral challenges. This review describes the epidemiology and natural history of perinatal arterial ischemic stroke (PAIS) and cerebral sinovenous thrombosis (CSVT), risk factors for these complications, recent evidence regarding treatment strategies, and current gaps in knowledge. Existing evidence demonstrates the multifactorial etiology of symptomatic ischemic stroke in neonates, which includes a combination of maternal, delivery, and neonatal factors. The importance of inherited thrombophilia in the pathophysiology and long-term outcomes of perinatal stroke requires additional study. At this time, there is no evidence to support routine extensive thrombophilia screening outside of a research setting. Despite the frequency of perinatal stroke and its association with substantial morbidity, treatment strategies are currently limited, and prevention strategies are nonexistent. Anticoagulation is rarely indicated in PAIS, and more work needs to focus on neuroprotective prevention and alternate treatment strategies. Anticoagulation does appear to be safe in CSVT and may prevent thrombus progression but clinical equipoise remains, and clinical trials are needed to obtain evidence regarding short- and long-term efficacy outcomes.

Mechanisms of perinatal arterial ischemic stroke

The incidence of perinatal stroke is high, similar to that in the elderly, and produces a significant morbidity and severe long-term neurologic and cognitive deficits, including cerebral palsy, epilepsy, neuropsychological impairments, and behavioral disorders. Emerging clinical data and data from experimental models of cerebral ischemia in neonatal rodents have shown that the pathophysiology of perinatal brain damage is multifactorial. These studies have revealed that, far from just being a smaller version of the adult brain, the neonatal brain is unique with a very particular and age-dependent responsiveness to hypoxia-ischemia and focal arterial stroke. In this review, we discuss fundamental clinical aspects of perinatal stroke as well as some of the most recent and relevant findings regarding the susceptibility of specific brain cell populations to injury, the dynamics and the mechanisms of neuronal cell death in injured neonates, the responses of neonatal blood-brain barrier to stroke in relation to systemic and local inflammation, and the long-term effects of stroke on angiogenesis and neurogenesis. Finally, we address translational strategies currently being considered for neonatal stroke as well as treatments that might effectively enhance repair later after injury.

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.

Association of preterm birth with brain malformations

This study investigates the rate of preterm birth in babies with congenital brain defects. Autopsy case reports of congenital brain anomalies were obtained from the literature. The control cases were from a large registry, a published report from the Metropolitan Atlanta Congenital Defects Program. From 428 publications, 1168 cases were abstracted that had autopsy studies of congenital brain defects and information on the gestational age (GA) at birth. The control data from Atlanta included 7738 infants with significant birth defects of any kind and 264,392 infants without birth defects. In the autopsy cases with brain defects, the mean GA was 36.6 wk, whereas the Atlanta data showed a mean GA of 39.3 wk for infants with no defects and a significantly shorter gestation of 38.1 wk (p < 0.0001) for infants with defects. In the Atlanta data, the rate of preterm birth was 9.3% for those with no defects compared with 21.5% (p < 0.0001) for those with defects. In the autopsy cases with brain defects, the rate of preterm birth was even greater (33.1%, p < 0.0001). In conclusion, these data show an association of brain defects with preterm births.

Advances in perinatal ischemic stroke

Increasingly distinct patterns of focal ischemic injury in the fetal and perinatal brain are recognized. Improved classification has afforded advances in risk factor identification, pathophysiology hypotheses, outcome prediction, and potential avenues for intervention. Cerebrovascular occlusion leading to perinatal stroke may be arterial or venous, symptomatic or subclinical, and it can occur across multiple time frames. Distinguishing causative factors from mere associations represents a major challenge with important implications for studies of pathogenesis. The adverse outcomes suffered by most children highlight the need for further research. Reviewed here are the current understandings, recent advancements, and future directions for research in perinatal ischemic stroke.

My approach to performing a perinatal or neonatal autopsy

An opportunity to determine the cause of death, factors that may have a role in it, and the extent and cause of malformations is provided by perinatal autopsy. The family may be assisted in finding closure after the death of their infant by the information obtained. Insight into classifying infants appearing normal into one of three groups, small, appropriate and large for gestational age, has been provided, as each group tends to have specific causes of death. In infants with congenital anomalies, patterns of malformation may lead us to the diagnosis. An accurate diagnosis is required to provide counselling for a subsequent pregnancy.

Stroke in the fetus and neonate

Multiple patterns of focal ischemic injury in the fetal and perinatal brain are now recognized as important causes of neurological disability in children. Strokes may be arterial or venous, symptomatic or subclinical, and can occur across multiple timeframes. Establishing the importance of an increasing number of potential risk factors and translating that knowledge into an improved understanding of pathophysiology are major challenges. Advanced neuroimaging has facilitated increased recognition of perinatal stroke and an improved understanding of plasticity mechanisms in the developing brain. Better outcome prediction will assist in patient selection for advancing neuroprotective strategies to reduce cerebral palsy and other adverse outcomes suffered by most children.

Perinatal infections and cerebral palsy

Infections of the mother, the intrauterine environment, the fetus, and the neonate can cause cerebral palsy through a variety of mechanisms. Each of these processes is reviewed. The recently proposed theory of cytokine-induced white matter brain injury and the systemic inflammatory response syndrome with multiple organ dysfunction syndrome is critically evaluated.

Cerebral palsy secondary to perinatal ischemic stroke

Congenital hemiplegia is the most common form of cerebral palsy in children born at term, and stroke is the number one cause. Neonatal ischemic stroke includes perinatal arterial ischemic stroke, presumed pre- or perinatal stroke, and cerebral sinovenous thrombosis, all of which have emerged as important contributors to cerebral palsy. Of increasing interest is how the overlapping list of associations and risks for stroke and cerebral palsy relate to each other. Stroke-induced injury is focal, and the preservation of normal areas of brain may afford unique opportunities for plastic adaptation. The implications of this essential difference are stressed in a discussion of how the epidemiology, pathophysiology, diagnosis, and therapeutic advancements in perinatal stroke relate to the outcome of cerebral palsy.

Increased prevalence of fetal thrombi in monochorionic-twin placentas

OBJECTIVE

Fetal vessel thrombosis has been related to pregnancy complications and adverse neonatal outcomes in singleton pregnancies, but the clinical and pathologic characteristics of fetal thrombosis in twin pregnancy are still ill defined.

METHODS

To clarify the characteristics of fetal thrombosis in twins, we reviewed the histology slides and medical records of live-born infants of twin pregnancies involving the live birth of at least 1 fetus (monochorionic: 389 cases; dichorionic: 780 cases) and singleton pregnancies (1162 cases).

RESULTS

The incidence of fetal thrombosis in monochorionic-twin pregnancies was significantly higher than that of dichorionic-twin and singleton pregnancies (5.1% vs 3.0% and 2.8%, respectively). The incidence of velamentous umbilical cord insertion in monochorionic- and dichorionic-twin placentas was also higher than in singleton placentas (12% and 7% vs 2%, respectively). Fetal thrombosis in twin placentas was associated with intrauterine growth restriction. In monochorionic twins, fetal thrombosis was associated with co-twin fetal death, but in dichorionic twins no correlation was identified. Microscopically, fetal vessel thrombosis in twin placentas was associated with vascular cushions (fibrous hyperplasia of fetal vessel), as is the case occasionally in singletons.

CONCLUSIONS

The incidence of fetal vessel thrombosis in monochorionic placentas was higher than that seen in dichorionic-twin placentas and singleton gestations. Fetal vessel thrombosis in twin pregnancies showed a correlation with intrauterine growth restriction, peripheral cord insertions, and major vascular cushions.

Maternal infection and adverse fetal and neonatal outcomes

Adverse pregnancy outcomes can follow direct placental, fetal, or neonatal infection, or preterm birth associated with vaginal, cervical, intrauterine, or even nonpelvic infections. These latter infections appear to be associated with the majority of very early preterm births, and may explain some of the long-term neurologic damage associated with preterm birth. Bacterial vaginosis and its associated intrauterine infections likely contribute far more to the overall burden of adverse pregnancy outcomes than the more classical perinatal infections such as rubella and syphilis.

Best practice no 178. Examination of the human placenta

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

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

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

The value of autopsy in determining the cause of failure to respond to resuscitation at birth

Autopsy is invaluable in identifying the causes of severe depression and very low Apgar score after birth and in assessing contributory conditions. Brain scans are increasingly used in the care of neonates who fail to respond to resuscitation at birth but their interpretation depends on the information gained from sound neuropathological studies. Asphyxia, both acute intrapartum asphyxia and chronic asphyxia, is an important cause of low Apgar scores. The gestational age and the nature of the asphyxial insult both have a profound influence on the ultimate pattern of injury. Asphyxia in the preterm brain tends to damage preferentially the white matter but some white matter damage is also seen in many infants who have an hypoxia-ischaemic insult at term though the predominant site of injury is to the central grey matter. The nature of the cellular damage and reactive change seen at autopsy is described. There is an association between low Apgar scores and intrauterine exposure to infection and maternal pyrexia. Detailed autopsy examination should include the search for infection. The placenta, cord and membranes should be examined in view of the mounting evidence of the association between intrauterine infection of the placenta and fetal membranes and prenatal brain damage. Additionally, the presence of placental thrombosis and infarction should be sought in relation to focal and global injury in the full term infant. Acquired prepartum lesions rarely cause the infant to present with a low Apgar score. The exception to this is severe damage to the brainstem and basal ganglia. Traumatic injury to the brain is now much less common than in previous decades. Subdural haemorrhage occurs more frequently than intraventricular or subarachnoid haemorrhage. Instrumental and assisted deliveries are associated with an increased incidence of subdural haemorrhage though these rarely cause significant long term damage. Careful autopsy, particularly of the neck and paravertebral tissues, spinal cord, brainstem and nerve roots is important where trauma is suspected. Tearing of nerve roots or fibre bundles in the spinal cord is readily demonstrated under the microscope using immunocytochemistry to beta-amyloid precursor protein. Disorders of the spinal cord, peripheral nerve and muscle as well as some metabolic diseases may cause a baby to be both floppy and weak. Metabolic disease, including peroxisomal disorders, non-ketotic hyperglycinaemia, lipid and glycogen storage disorders and mitochondrial diseases may cause profound hypotonia and respiratory failure at birth or shortly afterwards.

Stroke in newborn infants

The few days before and after birth are a time of special risk for stroke in both mother and infant, probably related to activation of coagulation mechanisms in this critical period. Arterial ischaemic stroke around the time of birth is recognised in about one in 4000 full-term infants, and may present with neurological and systemic signs in the newborn. Neonatal seizures are most commonly the clinical finding that triggers assessment. In other children, perinatal stroke is recognised only retrospectively, with emerging hemiparesis or seizures after the early months of life. Risk factors for perinatal stroke include hereditary or acquired thrombophilias and environmental factors. Perinatal stroke underlies an important share of congenital hemiplegic cerebral palsy, and probably some spastic quadriplegic cerebral palsy and seizure disorders. There is much to be learned about the natural history of perinatal stroke, and there are as yet no evidence-based strategies for prevention or treatment.

Fetal neurologic consultations

The pediatric neurologist can fulfill a useful role as a subspecialty consultant concerning the fetus with a suspected brain disorder, given that neurologic disease may occur before the intrapartum period. Brain disorders detected in the neonatal period may also reflect fetal brain damage before dysfunction is first documented. Medical conditions during the antepartum or intrapartum periods can alternatively predispose the fetus or neonate to express brain dysfunction at a later period, with either de novo or compounded brain injury. The pediatric neurologist must, therefore, consider maternal, placental, and fetal diseases on which a neonatal encephalopathy may be superimposed. This review article provides the neurologist with an integrative approach to fetal neurology, emphasizing perspectives from other subspecialties concerning maternal-fetal medicine, pathology, and neonatology, as well as other pediatric subspecialties. Evaluation of future strategies for either fetal or neonatal brain resuscitation will need to consider the developmental context in which a suspected brain injury occurred during the antepartum, intrapartum, and neonatal periods.

Antenatal causes of cerebral palsy: associations between inherited thrombophilias, viral and bacterial infection, and inherited susceptibility to infection

Cerebral palsy rates of 2 in every 1,000 births have varied little over the last 40 years, despite improvements in obstetric care. In the past, cerebral palsy was thought to be due to poor obstetric care and management; however, epidemiological studies have refuted this, suggesting that there is usually an antenatal timing to the neuropathology of cerebral palsy. There are many known risk factors for cerebral palsy, including multiple gestation, prematurity, and low birth weight. Recently, intrauterine infection, maternal pyrexia, and the presence of thrombophilic disorders (thrombophilia) have been identified as major risk factors for subsequent cerebral palsy. This review examines the links between intrauterine infection, the fetal inflammatory response, and thrombophilia as possible causes of cerebral palsy. The interactions of viral or bacterial infections during pregnancy, normal or abnormal fetal cytokine responses, and hereditary fetal thrombophilias as antenatal causes of the neuropathology of cerebral palsy are now areas of research priority.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the condition cerebral palsy, list the risk factors for the development of cerebral palsy, outline the ultrasound findings associated with cerebral palsy, and point out other conditions associated with cerebral palsy.

Cerebral infarctions in the fetus and neonate: maternal-placental-fetal considerations

Historical data, clinical examination findings, and laboratory information must be integrated along a variable timeline that includes antepartum, intrapartum, and postnatal time periods when cerebral infarction can occur, in the context of the neonates genetic endowment. Genetic susceptibility or prenatal acquired vulnerabilities regarding stroke syndromes may set in motion a cascade of molecular pathways that ultimately cause or exacerbate brain injury when the vulnerable child experiences adverse medical conditions. The clinician must consider maternal, placental, and fetal conditions on which a stroke syndrome may be superimposed, with or without additional brain injury from other pathogenic mechanisms. Evaluation of fetal and neonatal cerebral infarction requires knowledge of mechanisms of brain injury that cross medical disciplines and may involve consultation with maternal/fetal specialists, placental and pediatric pathologists, neonatologists, geneticists, and other pediatric subspecialties. Comprehensive evaluations of survivors of cerebral infarction are needed to better understand structural and functional plasticity of the developing brain after a cerebrovascular event in the fetal and neonatal periods.

The epidemiology of cerebral palsy in term infants

Half of cerebral palsy (CP) arises in infants of normal birthweight; yet, many fewer studies seek to identify risk factors for CP in term and near-term infants than in those born very prematurely. There has been no net decrease in the prevalence of CP in term and near-term infants over recent decades. Potentially asphyxiating birth complications account for a small minority of CP cases. Recent studies suggest that disorders of coagulation and intrauterine exposure to infection or inflammation are associated with risk of CP, and that both can be accompanied by signs of neonatal encephalopathy, the best available predictor of CP in term neonates. Therapeutic interventions directed at preventing interruption of oxygen supply have not been shown to reduce the occurrence of CP. There have not yet been studies examining whether medical interventions directed at infection or coagulation disorder can reduce the frequency of CP.

Livebirths with placental hemorrhagic endovasculitis: interlesional relationships and perinatal outcomes

BACKGROUND AND OBJECTIVE

Hemorrhagic endovasculitis (HEV) is a vasodisruptive alteration of fetal-placental blood vessels that has been associated with perinatal morbidity and mortality and abnormalities of growth and development. Clinicopathologic conditions that are often identified in pregnancies with HEV-affected placentas include villitis of unknown etiology, chorionic vessel thrombi, villous erythroblastosis, meconium staining, and maternal hypertension. The clinical implications of HEV are often disputed. This case-control study assesses the clinical relevance of HEV in placentas of viable infants and examines the interplay of coexistent intraplacental lesions.

METHODS

We reviewed clinical records and slides from 104 livebirths with placentas affected by HEV above a specified severity level (cases) and 104 matched livebirths with placentas that were not affected by HEV (controls). We evaluated incidences of perinatal complications with increasing HEV severity indices in placentas with and without coexistent lesions. Interlesional relationships were established by matching HEV severity indices with severity indices of coexistent lesions. Hemorrhagic endovasculitis was subcategorized into active, bland, and healed forms and clustered capillary lesions (hemorrhagic villitis).

RESULTS

Lesions that were frequently coexistent in HEV-affected placentas included villitis of unknown etiology, chorionic thrombi, villous fibrosis, erythroblastosis, and primary infarcts. Compared with the control group, the case group had higher incidences of abnormal fetal heart rate tracings (P <.003), fetal distress (P <.001), and growth restriction (P <.001). Increasing severities of HEV and coexistent lesions were associated with higher rates of perinatal complications. Complication rates were higher in HEV cases, with or without coexistent lesions. The complication rate was higher in cases affected by HEV and hemorrhagic villitis than in cases affected by HEV alone (P <.03). Significant interlesional relationships were evident between HEV and villitis of unknown etiology, chorionic thrombi, villous fibrosis, and erythroblastosis. CONCLUSIONS; Severe forms of HEV can occur in placentas of livebirths. The severity of HEV and associated lesions and the presence of hemorrhagic villitis have important clinical implications. Interlesional relationships between HEV and thrombotic, chronic inflammatory, and chronic vaso-occlusive lesions exist. Pregnancies with HEV-affected placentas with or without coexistent lesions are at risk for perinatal complications.

A topographical and clinical approach to examination of the placenta

Placental examination can be frustrating because of a perceived lack of usefulness and other limitations. A systematic examination employing a topographic approach that will eliminate gross omissions is described. This approach is used at the time of gross and histological examination. Histologically, the umbilical cord is examined from the surface to the inside, while the amniochorial membranes and placental disc are examined from the foetal to maternal surfaces. It is possible to accrue useful information when the placenta is examined this way. This information then can be correlated with the clinical details and indications for the placental examination.

Cerebrovascular disorders in children with the factor V Leiden mutation

Since 1995, at least 128 children with a cerebrovascular disorder, cerebral palsy, or both and the factor V Leiden mutation have been reported. The majority of these strokes were in the first year of life, many of them in the perinatal period. Two thirds had an additional exogenous risk factor for thrombosis, and 42% had another recognized endogenous prothrombotic risk factor in combination with the mutation. We review the association of the factor V Leiden mutation and a cerebrovascular disorder in children younger than 16 years of age and describe the clinical features of 8 children with cerebral palsy and the Leiden mutation. This mutation should be considered in the evaluation of children with a stroke or its sequelae, including infants with perinatal stroke.

Presumed pre- or perinatal arterial ischemic stroke: risk factors and outcomes

A subgroup of children with arterial ischemic stroke in the pre- or perinatal period present with delayed diagnosis. We identified 22 children who met the following criteria: (1) normal neonatal neurological history, (2) hemiparesis and/or seizures first recognized after two months of age, and (3) computed tomography or magnetic resonance imaging showing remote cerebral infarct. Laboratory evaluations included protein C, protein S, antithrombin, activated protein C resistance screen (APCR), Factor V Leiden (FVL), prothrombin gene defect, methylene tetrahydrofolate reductase variant (MTHFR), anticardiolipin antibody (ACLA), and lupus anticoagulant. Not all children received all tests. Age at last visit ranged from 8 months to 16.5 years (median 4 years). Twelve were boys. Fourteen had left hemisphere infarcts. Median age at presentation was 6 months. Eighteen had gestational complications. Fourteen children had at least transient coagulation abnormalities (ACLA = 11, ACLA + APCR = 1, APCR = 2 with FVL + MTHFR = 1); six of these children had family histories suggestive of thrombosis. Cardiac echocardiogram was unremarkable in the 15 tested. Outcomes included persistent hemiparesis in 22; speech, behavior, or learning problems in 12; and persistent seizures in five, with no evidence of further stroke in any patient. The persistence and importance of coagulation abnormalities in this group need further study.

Advances in prevention and treatment of cerebral palsy

In recent years there have been a number of advances in understanding of predisposing and protective factors in the development of cerebral palsy in infants. Multiple gestation births, maternal infection, and maternal and fetal thrombophilic conditions all predispose to the development of CP in the infant. Opportunities for prevention of CP may develop from an improved understanding of these factors and their mechanisms of operation. Similar progress has been made in the evaluation of treatments for CP and the effects of these treatments on the individual's impairment, function, and disability. Selective posterior rhizotomy and Botulinum toxin A are now widely used in the treatment of spasticity. The challenge remains to determine how effectively these promising interventions can alter long-term function and quality of life outcomes in children and adults with CP.

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

OBJECTIVE

The aim of this study was to determine the association of placental findings with cerebral palsy and related forms of neurologic impairment (NI) following birth at > or =37 weeks gestation (term).

DESIGN

In a retrospective comparison, placentas from 40 term infants with NI ascertained on the basis of clinicopathologic review for medicolegal consultation were compared with placentas from 176 consecutive meconium-stained term infants at low risk for NI.

RESULTS

After stratification for severity, 9 lesions were significantly increased in placentas from infants with NI: 5 lesions generally considered to occur within days of the time of labor and delivery (meconium-associated vascular necrosis, severe fetal chorioamnionitis, chorionic vessel thrombi, increased nucleated red blood cells, and findings consistent with abruptio placenta) and 4 lesions generally believed to have their onset long before labor and delivery (diffuse chronic villitis, extensive avascular villi, diffuse chorioamnionic hemosiderosis, and perivillous fibrin). Findings independently associated with NI by logistic regression in this descriptive study were severe fetal chorioamnionitis (odds ratio [OR], 13.2; 95% confidence interval [CI], 1.2-144); extensive avascular villi (OR, 9.0; 95% CI, 1.6-51); and diffuse chorioamnionic hemosiderosis (OR, 74.8; 95% CI, 6.3-894). The risk of NI increased as a function of the number of lesions present (OR, 10.1; 95% CI, 5.1-20 for each additional lesion), particularly when lesions generally considered to occur near the time of labor and those believed to occur well before labor were found in the same placenta (OR, 94.2; 95% CI, 11.9-747).

CONCLUSIONS

These findings suggest that placental pathology can contribute to an understanding of the mechanisms that contribute to NI at term.

Causes of cerebral palsy

Risk factors for cerebral palsy in term or near-term children include intrauterine exposure to infection or inflammation and disorders of coagulation. Interruption of the oxygen supply during birth contributes approximately 6% of spastic cerebral palsy. Low Apgar score, need for resuscitation, and seizures are nonspecific indicators of neonatal illness that do not identify cause. Although not entirely consistent, current evidence suggests that in utero infection may predispose very preterm and more mature infants to cerebral palsy and that antenatal exposure to steroids may be somewhat protective. Recognition of a broader set of causal possibilities encourages hope for new strategies for the prevention of cerebral palsy.

Fetal thrombotic vasculopathy in the placenta: cerebral thrombi and infarcts, coagulopathies, and cerebral palsy

Thrombi in the fetal circulation of the placenta cause a pattern of clustered fibrotic villi called fetal thrombotic vasculopathy (FTV), which has been associated with serious injuries to neonates, especially brain injuries. Correlation of FTV with visceral thrombi in autopsy specimens might lead to a more accurate estimate of the prevalence of somatic thrombi as a significant and underrecognized cause of prenatal injury or perinatal death, and show the potential validity of placental FTV as an indicator of thrombotic lesions in the fetus and newborns who survive. Clinicopathologic correlation was used to perform a 3-year retrospective autopsy review. We identified 16 cases (19%) among 84 perinatal autopsy specimens in which placental FTV was associated with stillbirth, intrapartum, or neonatal death. Two liveborn neonates survived 2.5 hours, and one for 24 hours; there was one intrapartum death, and the rest were stillborn. Clinical evidence of severe central nervous system (CNS) injury to two of the liveborn infants was evident at birth. Twelve stillborns died from 12 to 48 hours before delivery. Placental FTV had features of organization that clearly antedated the fetal death. Autopsy findings confirmed somatic thrombi in six cases (37.5%) of the 16 with FTV, including cerebral thrombi or infarcts (three cases), renal thromboemboli (three cases), and pulmonary thromboemboli (two cases). One mother had history of deep vein thrombosis, and four of eight tested had abnormal coagulation test results. Placental FTV indicates a significant probability of thrombi in the fetus and represents an important, possibly underrecognized cause of perinatal mortality and neonatal injury. Parental coagulopathy as a significant factor in prenatal injury and death deserves more comprehensive study. The placenta remains an undervalued and underutilized surgical specimen in the evaluation of perinatal injury, especially cerebral palsy.

The neurologically impaired child and alleged malpractice at birth

Controlled studies, improved epidemiologic and statistical techniques, and an increase in biological information on mechanisms of fetal and neonatal brain injury or maldevelopment have led to a better, although still imperfect, understanding of the cause of developmental disabilities. The role of asphyxia during the birth process is smaller than was once believed. Intrauterine exposure to infection, autoimmune and coagulation disorders, and problems specific to multiple pregnancies are risk factors for cerebral palsy. Electronic fetal monitoring and other observations during birth are unsatisfactory management guides, having enormously high rates of false-positive identification. There is no evidence that caesarean section can prevent cerebral palsy in term infants.

Neonatal cytokines and coagulation factors in children with cerebral palsy

We explored the association of inflammatory mediators and markers of autoimmune and coagulation disorders with cerebral palsy (CP), examining 53 analytes in dried neonatal blood of 31 children with spastic CP, most born at term, and 65 control children. Ultramicroanalysis was performed by recycling immunoaffinity chromatography coupled with laser-enhanced fluorescence and chemiluminescence detection. Reactive antibodies to lupus anticoagulant, anticardiolipin, antithrombin III, and the translational product of the factor V Leiden mutation were isolated by recycling immunoaffinity chromatography and measured by capillary electrophoresis with chemiluminescence-enhanced immunoassay. Higher concentrations of interleukins (ILs) 1, 8, 9, tumor necrosis factor-alpha, and RANTES were observed in these children with CP than in any control child. There were also substantial elevations of IL-6, 11, 13, and other chemokines and colony-stimulating factors in children with CP. Antiphospholipid antibody was present in a titer of 1:100 or greater in 4 children with CP and no control child. Using cuts empirically chosen by recursive partitioning, we found higher concentrations of antibody to antithrombin III, to a translational product of factor V Leiden mutation, and to proteins C and S in children with CP than in controls. We conclude that inflammation and these coagulation abnormalities, which have interacting pathways, are important in the etiology of CP.