Placental pathology and neonatal encephalopathy

Hypoxic-ischemic encephalopathy following intrapartum asphyxia: is it avoidable?

BACKGROUND

The proportion of term hypoxic-ischemic encephalopathy arising during intrapartum fetal surveillance remains unclear. Moreover, recent Cochrane review and other studies emphasized the need for research on the impact of admission cardiotocography and highlighted the necessity for a definition of "avoidable perinatal brain injury".

OBJECTIVE

To assess the impact of intrapartum asphyxia on neonatal hypoxic-ischemic encephalopathy occurrence and identify the proportion of cases that benefit from preventive measures.

STUDY DESIGN

This retrospective 20-year birth cohort study included admission and intrapartum cardiotocography recordings from spontaneous term (≥37 weeks of gestation) singleton deliveries at 7 maternity hospitals within the Helsinki University Hospital area, Finland, between 2005 and 2024. In newborns diagnosed with hypoxic-ischemic encephalopathy, cases following intrapartum asphyxia were identified by a normal cardiotocogram at admission, whereas antepartum exposure was indicated by an abnormal admission cardiotocogram. Cord blood gases, erythropoietin, and serum S100β concentrations were analyzed, and placentas underwent histopathological examination. Primary outcome was hypoxic-ischemic encephalopathy. Secondary outcome was fetal asphyxia, defined as the presence of severe or moderate acidemia.

RESULTS

Among 317,126 term newborns, 314 cases of hypoxic-ischemic encephalopathy were identified. Admission cardiotocogram was normal in 141 (44.9%) and abnormal in 173 (55.1%). Of those with a normal admission cardiotocogram, severe acidemia (umbilical artery pH <7.00 and/or base excess ≤-12.0 mmol/L) evolved in 127/141 (90.1%) and moderate acidemia (umbilical artery pH 7.09-7.00 and base excess -10.0 to -11.9 mmol/L) in 11/141 (7.8%). Excluding cases with a perinatal sentinel event and timely deliveries, 70 cases (49.6%) remained in which hypoxic-ischemic encephalopathy presumably developed during labor and was considered potentially avoidable. These findings suggest that in 22.3% (70/314), preventive measures should have been implemented. Newborns with abnormal cardiotocograms had higher median umbilical blood erythropoietin concentrations than those with normal admission cardiotocograms (112 U/L, interquartile range 22-1130 vs 29 U/L, interquartile range 7-680, P<.001), indicating more chronic hypoxia.

CONCLUSION

Of term newborns with hypoxic-ischemic encephalopathy and normal admission cardiotocogram, 98% were attributable to intrapartum asphyxia. Our findings indicate that half of the cases of intrapartum hypoxic-ischemic encephalopathy with a normal admission cardiotocogram were potentially avoidable, suggesting that one-fifth of all cases could have benefited from preventive measures. The findings underscore the role of optimal intrapartum care in preventing hypoxic-ischemic encephalopathy.

Placental and Umbilical Cord Anomalies Detected by Ultrasound as Clinical Risk Factors of Adverse Perinatal Outcomes. Case Series Review of Selected Conditions. Part 3: Vascular Anomalies of the Umbilical Cord and Fetoplacental Vascular Malperfusion

In the previous published reviews Part 1 and Part 2, we examined the association between placental and umbilical cord anomalies in relation to adverse perinatal outcomes. In this conclusive Part 3, only umbilical cord vascular anomalies are considered, together with the perinatal effects caused by maternal vascular malperfusion and the secondary fetal vascular malperfusion anomalies. Specifically, the review comprises the following umbilical cord pathologies: umbilical cord torsion/stricture, amniotic band syndrome and umbilical cord strictures/strangulation, umbilical cord hemorrhagic cyst, umbilical cord rupture/cord hemangioma, umbilical cord hematoma, and umbilical cord ulceration. A series of case presentations and a gallery of images have been included to illustrate this final review.

Placental histology for infants with hypoxic ischaemic encephalopathy compared with healthy controls: a case-control study

BACKGROUND

The role of the placenta in the development of hypoxic ischaemic encephalopathy (HIE) remains undefined. There is limited research comparing placental histology for infants with HIE and healthy controls. This is limiting our ability to understand its role in HIE. This study hypothesised that placental pathology is more common in infants with HIE compared with healthy infants and aimed to report the differences in placental histology between infants with HIE and healthy controls.

METHODS

A case-control study of infants with moderate andsevere HIE and healthy controls at a single tertiary Neonatal Intensive Care Unit. Placental histology was reviewed by one perinatal histopathologist using consensus guidelines.

RESULTS

Seventy-four cases and 98 controls were included. Cases had a higher incidence of pathology, including fetal vascular malperfusion, histological chorioamnionitis and delayed villous maturation.

CONCLUSION

This study demonstrates a higher incidence of placental pathology for infants born with HIE suggesting that the placenta is an important factor in the pathogenesis of HIE. Further research is required to delineate this relationship.

Integrated Transcriptomic and Metabolomic Profiling of the Placenta in a Dexamethasone-Induced Cleft Palate Rabbit Model

BACKGROUND

Cleft palate is a congenital malformation influenced by both genetic and environmental factors. Although environmental contributors have been extensively studied, the placenta-an essential organ that mediates maternal-fetal interactions and offers protection against environmental insults-remains poorly understood in this context. This study aimed to explore transcriptomic and metabolomic alterations in the placenta following maternal exposure to corticosteroids, using a dexamethasone-induced cleft palate rabbit model.

METHODS

Untargeted metabolomics and transcriptomics analyses were conducted on placental and amniotic fluid samples from fetuses with and without dexamethasone-induced cleft palate. Histopathological examination was performed to assess structural abnormalities in the placenta.

RESULTS

The cleft palate group exhibited marked placental pathologies, including fibrosis, calcification, and necrosis. Transcriptomic analysis identified 4744 differentially expressed genes, enriched in pathways related to hormone signaling, vascular development, and inflammation. Metabolomic profiling revealed significant changes in both placenta and amniotic fluid, especially in the urea cycle, aspartate metabolism, and nicotinate and nicotinamide metabolism. The urea cycle was particularly disrupted in the cleft palate group.

CONCLUSION

These findings reveal a strong association between placental structural and functional abnormalities and cleft palate formation in the dexamethasone-induced model, offering novel insights into the potential role of the placenta in cleft palate pathogenesis.

Neonatal encephalopathy and hypoxic-ischemic encephalopathy: the state of the art

Neonatal Encephalopathy (NE) remains a major cause of death and long-term severe disabilities, including epilepsy and cerebral palsy in term and near-term infants. The single most common cause is hypoxic-ischemic encephalopathy (HIE). However, there are many other potential causes, including infection, intracranial hemorrhage, stroke, brain malformations, metabolic disorders, and genetic causes. The appropriate management depends on both the specific cause and the stage of evolution of injury. Key tools to expand our understanding of the timing and causes of NE include aEEG, or even better, video EEG monitoring, neuro-imaging including cranial ultrasound and MRI, placental investigations, metabolic, biomarker, and genetic studies. This information is critical to better understand the underlying causes of NE. Therapeutic hypothermia improves outcomes after HIE, but there is still considerable potential to do better. Careful clinical and pre-clinical studies are needed to develop novel therapeutics and to help provide the right treatment at the right time for this high-risk population. IMPACT: Neonatal encephalopathy is complex and multifactorial. This review seeks to expand understanding of the causes, timing, and evolution of encephalopathy in newborns. We highlight key unanswered questions about neonatal encephalopathy.

Umbilical cord blood pTau217 and BD-tau are associated with markers of neonatal hypoxia: a prospective cohort study

Objective

Current methods for early detection of hypoxic-ischemic encephalopathy (HIE) are limited by lack of specificity, cost, and time constraints. Blood tau protein concentrations reflect neuropathology in adults. This study examines tau as a potential HIE biomarker in neonates by relating cord blood levels to short-term fetomaternal outcomes. We aimed to examine 1) association of BD-tau with non-reassuring fetal status; 2) correlations between cord blood tau and other hypoxia biomarkers; 3) associations between tau levels and risk factors for fetomaternal morbidity; 4) associations between tau levels and short-term fetomaternal outcome.

Methods

107 maternal participants were prospectively recruited at Royal Prince Alfred Hospital-a large Australian tertiary referral centre. Simoa analysis detected umbilical cord blood pTau217 and brain-derived (BD)-tau levels.

Results

Of 509 deliveries, cord blood was analysed in 107/110 recruited maternal participants. BD-tau correlated with non-reassuring fetal status (OR=3.0;95%CI=1.6- 5.7;p=0.001), though not when adjusting for mode of delivery and gestational age. BD-tau was higher in vaginal deliveries, and positively associated with pTau217, NfL, and lactate (p<0.001), and negatively associated with pH and base excess. pTau217 was higher in preterm neonates and was associated with neurofilament light chain (Spearman's rho=0.44,p<0.001). BD-tau and pTau217 were associated with maternal hypertension and placental abnormalities.

Conclusions

Cord blood BD-tau correlates with surrogate markers of fetal hypoxia, whilst pTau217 may represent a marker of neurodevelopment. Further studies could explore whether these findings translate to clinical use of tau as an HIE biomarker.

Funding

US National Institutes of Health (grant:R01AG063849-01).

Chorioamnionitis and Two-Year Outcomes in Infants with Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To determine if chorioamnionitis is associated with an increased risk of adverse 2-year outcomes among infants with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

This cohort study included all infants with moderate to severe HIE treated with therapeutic hypothermia and enrolled on the High-dose Erythropoietin for Asphyxia and Encephalopathy Trial. Clinical chorioamnionitis (CC) was defined as a diagnosis made by a treating obstetrician and histologic chorioamnionitis (HC) was defined as placental inflammation observed on histology. We used proportional odds regression to determine the associations between CC, HC, and an ordinal 2-year neurodevelopmental outcome measure: no neurodevelopmental impairment (NDI), mild NDI, moderate NDI, severe NDI, or death.

RESULTS

Of 500 infants, 65 (13%) were exposed to CC. Of 317 infants with placental data available, 125 (39%) were exposed to HC. Infants exposed to CC (odds ratio 0.57, 95% CI 0.34-0.95) and those exposed to HC (odds ratio 0.62, 95% CI 0.40-0.96) had a lower severity of primary outcome than unexposed infants. Infants exposed to chorioamnionitis also had lower frequencies of sentinel events (CC: P = .001; HC: P = .005), central pattern magnetic resonance imaging brain injury (CC: P = .02; HC: P = .02), and electroencephalogram background abnormalities (CC: P = .046; HC: P = .02), compared with unexposed infants.

CONCLUSIONS

Infants with HIE who were exposed to chorioamnionitis had lower severity of 2-year outcomes than unexposed infants. Our findings suggest that chorioamnionitis may lead to a lower severity of brain dysfunction than other pathophysiologic mechanisms of encephalopathy.

Utility of Cranial Ultrasound to Investigate Brain Injury in Hypoxic-Ischemic Encephalopathy

BACKGROUND

With increasing availability of brain magnetic resonance imaging (MRI) in high-income countries, cranial ultrasound (cUS) is used less frequently to evaluate infants with hypoxic-ischemic encephalopathy (HIE). This study aimed to correlate findings of brain injury on early postnatal cUS with brain injury on neonatal brain MRI performed as part of routine clinical care for near-term and term infants with moderate to severe HIE.

METHODS

This was a retrospective cohort study comparing early postnatal cUS and later neonatal brain MRI using scoring systems with prognostic validity to assess brain injury in near-term/term infants with moderate or severe HIE. Infants were born between 2010 and 2021 and were treated at a single tertiary neonatal intensive care unit.

RESULTS

A total of 94 infants were included in this study. cUS was performed in the first five days after birth and brain MRI at a median of 6.7 days (interquartile range 5.4, 7.9). Findings of white matter injury on cUS <24 hours and gray matter injury on cUS >48 hours correlated with similar nature and severity of brain injury on brain MRI. Subgroup analyses of cUS performed <24 and >48 hours and contemporaneous brain MRI performed on days 3 to 5 provided stronger evidence for correlations of brain injury between neuroimaging modalities.

CONCLUSION

This study provides evidence for the correlation of findings of brain injury between cUS and brain MRI. Early postnatal cUS can provide information on potential findings on brain MRI and may help inform outcome of newborns in low-middle income countries and situations where MRI is not clinically possible.

Placental inflammatory response and association with the severity of neonatal hypoxic ischemic encephalopathy

BACKGROUND

Placental lesions are associated with worse neonatal outcomes, but their association with neonatal hypoxic-ischemic encephalopathy (HIE), including the full range of severity from mild to severe HIE, has not been well described.

OBJECTIVE

To determine the association of acute and chronic placental lesions with mild versus moderate to severe HIE; secondarily, to assess the impact of multiple placental lesions on severity of HIE.

METHODS

This retrospective study of prospectively collected data included neonates born at ≥36 weeks, with a birth weight of >1800 g, diagnosed with HIE between January 2012 and November 2022. The cohort was divided into those with mild versus moderate to severe HIE, based on the modified Sarnat staging. Placental histologic diagnoses were made according to the Amsterdam Placental Workshop Group Consensus Statement. Placental pathologic lesions were classified into acute inflammation with attention to stages and grades of maternal and fetal inflammatory responses (MIR and FIR, respectively), maternal vascular malperfusion, fetal vascular malperfusion, villitis of unknown etiology, and other lesions. Chi-square and Fisher's exact test were used to compare rates of placental pathologies between mild and moderate to severe HIE groups.

RESULTS

Of 394 neonates ≥36 weeks' gestation diagnosed with HIE, 172 had mild HIE and received supportive care, while 180 had moderate to severe HIE and underwent therapeutic hypothermia. 42 patients were excluded due to lack of placental pathology reports. FIR was significantly associated with moderate to severe HIE vs. mild HIE (53 % vs. 38 %, P < 0.01). Higher grade and stage of FIR was also associated with worse severity of HIE (moderate to severe HIE showed FIR stage ≥2 in 81 % and grade 2 in 15 % vs. 34 % and 3 % in those with mild HIE, respectively). MIR was diagnosed in more placentas from the moderate to severe HIE group (58 % vs. 47 %, P = 0.04) with higher stage and grade MIR in patients with moderate to severe HIE (86 % with MIR stage ≥2 and 19 % with MIR grade 2). High-grade (patchy/diffuse) chronic villitis was more prevalent in the moderate to severe HIE group vs. mild HIE group (18 % vs. 8 %, P < 0.01).

CONCLUSION

There is a higher prevalence of placental inflammatory lesions in neonates with moderate to severe HIE compared to those with mild HIE.

Effect of abnormal placental cord insertion on hemodynamic change of umbilical cord in a tertiary center: a prospective cohort study

BACKGROUND

Our study aims to evaluate the umbilical vein (UV) hemodynamic change in the prenatal cohort of pregnancies diagnosed with abnormal placental cord insertion (aPCI).

METHODS

From January 2022 to December 2022, the fetal umbilical cord insertion site was sonographically examined in singleton fetuses, and umbilical cord blood flow was calculated. The umbilical artery and UV Doppler flow indexes were assessed in cases of normal and abnormal cord insertion.

RESULTS

Among 570 singleton fetuses between 18 + 0 and 40 + 6 weeks of gestation in the final study, the umbilical vein blood flow (UVBF) in the 3 groups of normal umbilical cord insertions, marginal umbilical cord insertions, and velamentous umbilical cord insertions was 145.39 ml/min, 146.18 ml/min, and 93.96 ml/min, respectively. UVBF was significantly lower in the velamentous cord insertion (VCI) group than in the other groups (P < 0.05). Compared with the normal cord insertions group, lower birth weight (2820 ± 527 g vs. 3144 ± 577 g, P < 0.05), delivery at an earlier gestational age (38.0 ± 1.55 weeks vs. 38.8 ± 2.34 weeks, P < 0.05), higher bicarbonate (25.08 ± 1.72 mmol/L vs. 22.66 ± 4.05 mmol/L, P < 0.05), and higher standard base excess (-1.14 ± 1.50 mmol/L vs. -3.30 ± 3.22 mmol/L, P < 0.05) were found in the VCI group.

CONCLUSIONS

We observed lower UVBF volume with aPCI. Hence, we propose UVBF analysis to evaluate fetal aPCI according to UV hemodynamics as an advisory in prenatal care. This would be useful and improve obstetricians' clinical explanation about the potential prenatal consequences so that parents can opt for future prenatal care during pregnancy.

Can miRNAs in MSCs-EVs Offer a Potential Treatment for Hypoxic-ischemic Encephalopathy?

Neonatal hypoxic-ischemic encephalopathy (HIE) is a critical condition resulting from impaired oxygen and blood flow to the brain during birth, leading to neuroinflammation, neuronal apoptosis, and long-term neurological deficits. Despite the use of therapeutic hypothermia, current treatments remain inadequate in fully preventing brain damage. Recent advances in mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) offer a novel, cell-free therapeutic approach, as these EVs can cross the blood-brain barrier (BBB) and deliver functional microRNAs (miRNAs) to modulate key pathways involved in inflammation and neuroprotection. This review examines how specific miRNAs encapsulated in MSC-EVs-including miR-21, miR-124, miR-146, and the miR-17-92 cluster-target the complex inflammatory responses that drive HIE pathology. By modulating pathways such as NF-κB, STAT3, and PI3K/Akt, these miRNAs influence neuroinflammatory processes, reduce neuronal apoptosis, and promote tissue repair. The aim is to assess the therapeutic potential of miRNA-loaded MSC-EVs in mitigating inflammation and neuronal damage, thus addressing the limitations of current therapies like therapeutic hypothermia.

Associations between maternal gestational diabetes mellitus and offspring cerebral palsy: a two-sample Mendelian randomization study

Background

Observational studies on the association between gestational diabetes mellitus (GDM) during pregnancy and pediatric neurological disorders (PNDs) such as cerebral palsy (CP), autism spectrum disorders (ASD), and epilepsy (EP) in offspring have yielded mixed findings, creating ambiguity in causal interpretations. The direct link between GDM and these PNDs remains unclear. Elucidating this connection is vital for developing effective early intervention strategies during pregnancy to mitigate the risk of PNDs in the offspring. This study utilizes a two-sample (2-sample) Mendelian randomization (MR) approach to investigate the causal relationship between GDM and its impact on CP, ASD, and EP in offspring.

Methods

We employed 2-sample MR using 6 single nucleotide polymorphisms (SNPs) strongly associated with GDM. Summary-level data for CP, ASD, and EP were obtained from the Integrative Epidemiology Unit (IEU) Open Genome-Wide Association Study (GWAS) project, encompassing sample sizes of 217,278, 46,351, and 463,010, respectively. The robustness of our findings was assessed using the inverse variance-weighted (IVW) method along with additional sensitivity analyses.

Results

The results demonstrate that GDM is associated with a higher risk of offspring CP as determined by the IVW method [odds ratio (OR): 1.74; 95% confidence interval (CI): 1.27-2.37; P<0.001]. In contrast, no association was observed between GDM and ASD or EP. Additionally, alternative methods for sensitivity analyses showed consistent results, and there was no pleiotropy detected using MR-Egger regression (P=0.48).

Conclusions

This study provides strong evidence supporting a positive causal relationship between genetically predicted GDM and the increased risk of offspring CP, with no observed correlation found with ASD or EP.

Overview of reproductive and pregnancy health principles and practice used by maternal-fetal medicine specialists for fetal-neonatal neurology consultants

Unique from other fetal anatomical systems, the central nervous system (CNS) starts development early in the embryonic period shortly after fertilization before most patients are even aware they are pregnant. Maturation throughout pregnancy involve complicated structural and functional changes, most likely below the resolution of testing to detect. During this time, the fetal CNS is susceptible to lesions that reflect trimester-specific adverse events. Neonatal neurological status with childhood sequelae can result from combinations of antenatal, peripartum and neonatal adverse events. Person-specific clinical management choices must consider the timing of multiple mechanisms that can alter neurodevelopment including genetic causes, aetiologies after conception as well as communicable and non-communicable conditions that result in anomalous or destructive brain lesions. The appearance of the fetal brain also changes significantly through gestation as different structures mature and the cerebral cortex in particular increases in size and complexity. Therefore, obstetrical imagers and maternal fetal medicine physicians need to be aware of the expected evolving appearances of the healthy fetal brain as the fetus advances in gestation. Often when fetal CNS pathology is detected or anticipated during pregnancy, there is understandably significant parental anxiety regarding the long-term implications of their child's neurodevelopmental prognosis. In these instances, Maternal Fetal Medicine specialists often collaborate with Pediatric Neurologists in the antenatal period regarding diagnoses that anticipate neonatal or later childhood neurologic sequelae. Potential adverse outcomes are discussed with prospective parents to be integrated into choices based on shared decisions.

Advancing our knowledge of placental function and how it relates to the developing fetal brain

Perinatal medicine has made significant advancements in recent decades. This has improved care and outcomes for infants. As we strive to improve neurodevelopmental outcomes, we must understand the influence the maternal/placental/fetal (MPF) triad has on fetal development and postnatal health and disease. Our understanding of the MPF triad remains incomplete, however research is continuing to develop our understanding. Through further research and incorporating what is currently known into how we deliver perinatal care, we have the opportunity to improve outcomes for infants. This review focuses on what is currently known about the structure and function of the placenta and the influence of the MPF triad. Current modalities for assessment of the MPF triad and future avenues for research will also be discussed. Understanding the relationship between the MPF triad, neurodevelopment and long-term health and disease has the potential to open new avenues for disease prevention and treatment through the lifespan.

Uncovering the Role of Inflammation with Asphyxia in the Newborn

The etiology of perinatal brain injury is multifactorial, but exposure to perinatal hypoxiaischemia (HI) is a major underlying factor. This review discusses the role of exposure to infection/inflammation in the evolution of HI brain injury, changes in immune responsiveness to subsequent inflammatory challenges after HI and modulation of neural outcomes with interaction between perinatal HI and inflammatory insults. The authors critically assess the clinical and preclinical evidence for the neuroprotective efficacy of therapeutic hypothermia and other anti-inflammatory treatments for inflammation-sensitized HI injury.

Neonatal Encephalopathy is a Complex Phenotype Representing Reproductive and Pregnancy Exposome Effects on the Maternal-Placental-Fetal Triad

Reproductive, pregnancy, and placental exposomes influence the fetal neural exposome through toxic stressor interplay, impairing the maternal-placental-fetal (MPF) triad. Neonatal encephalopathy represents different clinical presentations based on complex time-dependent etiopathogenetic mechanisms including hypoxia-ischemia that challenge diagnosis and prognosis. Reproductive, pregnancy, and placental exposomes impair the fetal neural exposome through toxic stressor interplay within the MPF triad. Long intervals often separate disease onset from phenotype. Interdisciplinary fetal-neonatal neurology training, practice, and research closes this knowledge gap. Maintaining reproductive health preserves MPF triad health with life-course benefits.

Causes and Terminology in Neonatal Encephalopathy: What is in a Name? Neonatal Encephalopathy, Hypoxic-ischemic Encephalopathy or Perinatal Asphyxia

Neurologic depression in term/near-term neonates (neonatal encephalopathy, NE) is uncommon with modern obstetric care. Asphyxial birth, with or without co-factors, accounts for a minority of NE, while maldevelopment (congenital malformations, growth aberrations, genetic, metabolic and placental abnormalities) plays an enlarging role in identifying etiologic subgroups of NE. The terms NE and hypoxic-ischemic encephalopathy (HIE) have not been employed uniformly, hampering research and clinical care. The authors propose the term NE as an early working-diagnosis, to be supplemented by a diagnosis of NE due to HIE or to other factors, as a final diagnosis once workup is complete.

Perinatal compromise affects development, form, and function of the hippocampus part one; clinical studies

The hippocampus is a neuron-rich specialised brain structure that plays a central role in the regulation of emotions, learning and memory, cognition, spatial navigation, and motivational processes. In human fetal development, hippocampal neurogenesis is principally complete by mid-gestation, with subsequent maturation comprising dendritogenesis and synaptogenesis in the third trimester of pregnancy and infancy. Dendritogenesis and synaptogenesis underpin connectivity. Hippocampal development is exquisitely sensitive to perturbations during pregnancy and at birth. Clinical investigations demonstrate that preterm birth, fetal growth restriction (FGR), and acute hypoxic-ischaemic encephalopathy (HIE) are common perinatal complications that alter hippocampal development. In turn, deficits in hippocampal development and structure mediate a range of neurodevelopmental disorders, including cognitive and learning problems, autism, and Attention-Deficit/Hyperactivity Disorder (ADHD). In this review, we summarise the developmental profile of the hippocampus during fetal and neonatal life and examine the hippocampal deficits observed following common human pregnancy complications. IMPACT: The review provides a comprehensive summary of the developmental profile of the hippocampus in normal fetal and neonatal life. We address a significant knowledge gap in paediatric research by providing a comprehensive summary of the relationship between pregnancy complications and subsequent hippocampal damage, shedding new light on this critical aspect of early neurodevelopment.

Placental fetal vascular malperfusion, neonatal neurologic morbidity, and infant neurodevelopmental outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the association of placental fetal vascular malperfusion lesions with neonatal brain injury and adverse infant neurodevelopmental outcomes.

DATA SOURCES

PubMed and Medline, Scopus, and Cochrane databases were searched from inception to July 2022.

STUDY ELIGIBILITY CRITERIA

We included cohort and case-control studies reporting the associations of fetal vascular malperfusion lesions with neonatal encephalopathy, perinatal stroke, intracranial hemorrhage, periventricular leukomalacia, and infant neurodevelopmental and cognitive outcomes.

METHODS

Data were analyzed by including fetal vascular malperfusion lesions as an exposure variable and brain injuries or neurodevelopmental impairment as outcomes using random-effects models. The effect of moderators, such as gestational age or study type, was assessed by subgroup analysis. Study quality and risk of bias were assessed by applying the Observational Study Quality Evaluation method.

RESULTS

Out of the 1115 identified articles, 26 were selected for quantitative analysis. The rates of neonatal central nervous system injury (neonatal encephalopathy or perinatal stroke) in term or near-term infants were more common among fetal vascular malperfusion cases (n=145) than among controls (n=1623) (odds ratio, 4.00; 95% confidence interval, 2.72-5.90). In premature deliveries, fetal vascular malperfusion lesions did not influence the risk of intracranial hemorrhage or periventricular leukomalacia (odds ratio, 1.40; 95% confidence interval, 0.90-2.18). Fetal vascular malperfusion-associated risk of abnormal infant neurodevelopmental outcome (314 fetal vascular malperfusion cases and 1329 controls) was modulated by gestational age being higher in term infants (odds ratio, 5.02; 95% confidence interval, 1.59-15.91) than in preterm infants (odds ratio, 1.70; 95% confidence interval, 1.13-2.56). Abnormal infant cognitive development and mental development were more common among fetal vascular malperfusion cases (n=241) than among controls (n=2477) (odds ratio, 2.14; 95% confidence interval, 1.40-3.27). The type of study (cohort vs case-control) did not influence the association between fetal vascular malperfusion and subsequent infant brain injury or abnormal neurodevelopmental outcome.

CONCLUSION

The findings of cohort and case-control studies indicate a considerable association between fetal vascular malperfusion placental lesions and increased risk of brain injury in term neonates, and neurodevelopmental impairment in both term and preterm infants. A diagnosis of placental fetal vascular malperfusion should be taken into consideration by both pediatricians and neurologists during the follow-up of infants at risk of adverse neurodevelopmental outcomes.

The association of placental pathology and neurodevelopmental outcomes in patients with neonatal encephalopathy

BACKGROUND

Studies conflict on how acute versus chronic placental pathology impacts outcomes after neonatal encephalopathy from presumed hypoxic-ischemic encephalopathy (HIE). We examine how outcomes after presumed HIE vary by placental pathology categories.

METHODS

We performed retrospective chart review for neonates with presumed HIE, regardless of severity, focusing on 50 triads for whom placental specimens were available for re-review. Placentas were categorized as having only acute, any chronic, or no lesions. Primary outcomes included in-hospital morbidity/mortality and long-term neurodevelopmental symptoms. Secondary outcomes assessed neonatal MRI and EEG.

RESULTS

Demographics did not differ between groups. Forty-seven neonates were treated with therapeutic hypothermia. Placental acuity category was not associated with primary or secondary outcomes, but clinical and/or histopathological chorioamnionitis was associated with abnormal EEG background and post-neonatal epilepsy (16.7%, n = 3 with chorioamnionitis versus 0%, n = 0 without chorioamnionitis, p = 0.04).

CONCLUSIONS

When grouped by acute, chronic, or absent placental lesions, we observed no association with in-hospital, neurodevelopmental, MRI, or EEG outcomes. When reanalyzed by the presence of chorioamnionitis, we found that chorioamnionitis appeared to be associated with a higher risk of EEG alterations and post-neonatal epilepsy. Despite our limited sample size, our results emphasize the critical role of placental examination for neuroprognostication in presumed HIE.

IMPACT

Neonatal encephalopathy presumed to result from impaired fetal cerebral oxygenation or blood flow is called hypoxic ischemic encephalopathy (HIE). Prior studies link placental pathology to various outcomes after HIE but disagree on the impact of acute versus chronic pathology. Our study determines that neurodevelopmental outcomes, in-hospital outcomes, injury on MRI, and EEG findings in patients with HIE are not differentially associated with acute versus chronic placental pathology. Chorioamnionitis is associated with an increased risk of abnormal EEG patterns and post-neonatal epilepsy. Histopathologic chorioamnionitis without clinical symptoms is common in HIE, emphasizing the crucial role of placental pathology for neuroprognostication.

Leveraging the placenta to advance neonatal care

The impact of placental dysfunction and placental injury on the fetus and newborn infant has become a topic of growing interest in neonatal disease research. However, the use of placental pathology in directing or influencing neonatal clinical management continues to be limited for a wide range of reasons, some of which are historical and thus easily overcome today. In this review, we summarize the most recent literature linking placental function to neonatal outcomes, focusing on clinical placental pathology findings and the most common neonatal diagnoses that have been associated with placental dysfunction. We discuss how recent technological advances in neonatal and perinatal medicine may allow us to make a paradigm shift, in which valuable information provided by the placenta could be used to guide neonatal management more effectively, and to ultimately enhance neonatal care in order to improve our patient outcomes. We propose new avenues of clinical management in which the placenta could serve as a diagnostic tool toward more personalized neonatal intensive care unit management.

Maternal and Fetal Risk Factors for Neonatal Hypoxic-Ischemic Encephalopathy: A Retrospective Study

Background

Neonatal hypoxic-ischemic encephalopathy (HIE) leads to different degree of neurological sequelae. The incidence of HIE is relatively high, and the risk factors associated with HIE are still controversial. It is necessary to identify the risk factors associated with HIE.

Methods

A total of 258 neonates (110 HIE patients and 148 controls) were enrolled in this study. The characteristics of pregnant women and fetuses during pregnancy and delivery were compared between HIE patients and controls, and the risk factors of HIE were analyzed.

Results

The proportions of premature infants, low-birth-weight infants and the levels of 1-minute Apgar score, 5-minute Apgar score in HIE group were significantly lower than those in control group, while the proportion of amniotic fluid contamination in the HIE group was significantly higher than those of the controls. When HIE was taken as the end point of 1-minute Apgar score, and 5-minute Apgar score, the cut-off value of 1-minute Apgar score was 3, and 5-minute Apgar score was 7 by receiver operating characteristic (ROC) curve analysis. The results of multivariate logistic regression analysis showed that low birth weight (<2.5 kg) (OR 1.780, 95% CI: 0.124-25.463, P=0.016), amniotic fluid contamination (OR 3.223, 95% CI: 1.049-9.901, P=0.041), low 1-minute Apgar score (≤3) (OR 92.425, 95% CI: 15.522-550.343, P<0.001), and low 5-minute Apgar score (≤7) (OR 12.641, 95% CI: 2.894-55.227, P=0.001) may increase risk of HIE. In addition, amniotic fluid contamination, low 1-minute Apgar score (≤3), and low 5-minute Apgar score (≤7) may increase risk of HIE among newborns born to women without previous childbearing history, but not in newborns born to women with previous childbearing history.

Conclusion

Low birth weight (<2.5 kg), amniotic fluid contamination, low 1-minute Apgar score (≤3), and 5-minute Apgar score (≤7) may increase risk of HIE.