Massive Perivillous Fibrin Deposition and Chronic Histiocytic Intervillositis a Complication of SARS-CoV-2 Infection

Maternal Fever and Reduced Fetal Movement as Predictive Risk Factors for Adverse Neonatal Outcome in Cases of Congenital SARS-CoV-2 Infection: A Meta-Analysis of Individual Participant Data from Case Reports and Case Series

OBJECTIVES

To determine risk factors for primary and secondary adverse neonatal outcomes in newborns with congenital SARS-CoV-2 infection.

DATA SOURCES

PubMed/MEDLINE and Google Scholar from January 2020 to January 2022.

STUDY ELIGIBILITY CRITERIA

newborns delivered after 24 weeks of gestation with confirmed/possible congenital SARS-CoV-2 infection, according to standard classification criteria.

METHODS

Execution of the IPD analyses followed the PRISMA-IPD statement. Univariate non-parametric tests compared numerical data distributions. Fisher's exact or Chi-square test determined categorical variables' statistical significance. Multivariate logistic regression revealed risk factors for adverse neonatal outcome.

RESULTS

Maternal fever was associated with symptomatic congenital infection (OR: 4.55, 95% CI: 1.33-15.57). Two-thirds of women that reported decreased fetal movements were diagnosed with IUFD (p-value = 0.001). Reduced fetal movement increased the risk of intrauterine fetal death by 7.84 times (p-value = 0.016, 95% CI: 2.23-27.5). The risk of stillbirth decreased with gestational age at the time of maternal infection (p-value < 0.05, OR: 0.87, 95% CI: 0.79-0.97).

CONCLUSIONS

Maternal fever and perception of reduced fetal movement may be predictive risk factors for adverse pregnancy outcome in cases with congenital SARS-CoV-2 infection.

A Case Series on Pregnant Patients with Mild Covid-19 Infection and Signs of Severe Placental Insufficiency

In this case series, we present five cases of pregnant women who sought medical attention for reduced fetal movements with an ongoing mild maternal Covid-19 infection at a Stockholm hospital in Spring of 2021. At the time of admission, the patients were in gestational week between $24+0$ and $33+5$ . Abdominal ultrasound at the hospital showed no fetal movements, and cardiotocography (CTG) was pathological. All women delivered via cesarean section within 24 hours after admission. Placental pathology in all cases showed massive perivillous fibrin deposition and extensive histiocytic intervillositis. All placentas were Covid-19 polymerase chain reaction (PCR) positive. The infants were Covid-19 PCR negative. Consistent with other published case reports, we hypothesize that Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect the placenta resulting in massive perivillous fibrin deposition and histiocytic intervillositis leading to acute placental insufficiency and fetal hypoxia. The absence of intrauterine growth restriction also augments the theory of an acute onset of placental insufficiency due to the Covid-19 infection.

The Histopathological "Placentitis Triad" Is Specific for SARS-CoV-2 Infection, and Its Acute Presentation Can Be Associated with Poor Fetal Outcome

(1) Background: Placental histological lesions reported in relation with SARS-CoV-2 infection are various, with potential consequences such as fetal growth retardation, prematurity or stillbirth/neonatal death. We report here on a placental pathological association which could be specific for SARS-CoV-2 infection and associated with poor fetal outcome; (2) Methods: We collected all the placental pathological examinations performed in Brest University Hospital (France) since the beginning of COVID-19 pandemic with a known maternal SARS-CoV-2 infection and a poor pregnancy outcome. In these cases, we described the pathological lesions and we searched for these lesions in a large series of placentas collected and examined in the same institution before the SARS-CoV-2 pandemic; (3) Results: Three cases with severe fetal outcome (tardive abortion, prematurity, neonatal death), from the first to the third trimesters of pregnancy, were included. The three cases showed features of massive and acute "placentitis triad" consisting in massive perivillous fibrin deposition, sub-acute intervillositis and trophoblastic necrosis. This association was not encountered in any of 8857 placentas analyzed during the period between 2002 and 2012 in our institution; (4) Conclusions: The "placentitis triad" appears to be specific for SARS-CoV-2 infection and, in case of massive and acute presentation, could result in poor fetal outcome.

Outcome of Newborns with Confirmed or Possible SARS-CoV-2 Vertical Infection-A Scoping Review

Severe acute respiratory syndrome virus 2 (SARS-CoV-2), the virus that causes 2019 coronavirus disease (COVID-19), has been isolated from various tissues and body fluids, including the placenta, amniotic fluid, and umbilical cord of newborns. In the last few years, much scientific effort has been directed toward studying SARS-CoV-2, focusing on the different features of the virus, such as its structure and mechanisms of action. Moreover, much focus has been on developing accurate diagnostic tools and various drugs or vaccines to treat COVID-19. However, the available evidence is still scarce and consistent criteria should be used for diagnosing vertical transmission. Applying the PRISMA ScR guidelines, we conducted a scoping review with the primary objective of identifying the types, and examining the range, of available evidence of vertical transmission of SARS-CoV-2 from mother to newborn. We also aimed to clarify the key concepts and criteria for diagnosis of SARS-CoV-2 vertical infection in neonates and summarize the existing evidence and advance the awareness of SARS-CoV-2 vertical infection in pregnancy. Most studies we identified were case reports or case series (about 30% of poor quality and inconsistent reporting of the findings). Summarizing the existing classification criteria, we propose an algorithm for consistent diagnosis. Registration: INPLASY2022120093.

A case report: Hypoxic ischemic encephalopathy & pneumonia in a neonate after SARS-CoV-2 intrauterine transmission

Severe acute respiratory coronavirus 2 (SARS-CoV-2) is primarily transmitted via respiratory droplet or aerosol route. However, there is mounting evidence for intrauterine transmission. We report on a late preterm infant with suspected intrauterine acquisition of SARS-CoV-2 who experienced birth depression, hypoxic ischemic encephalopathy, multisystem organ involvement, and late onset COVID-19 pneumonia [22].

Mother to Newborn Transmission of SARS-CoV-2 Infection: Evolution of Evidence in 1.5 Years of COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) pandemic caused significant mortality and morbidity in people of all age groups worldwide. Given the uncertainty regarding the mode of transmission and potential effects of COVID-19 on pregnant mothers and their newborns, guidelines for taking care of maternal-newborn dyads have evolved tremendously since the pandemic began. There has been an enormous influx of published materials regarding the outcomes of mothers and newborns. Still, multiple knowledge gaps regarding comprehensive information about risk to the mothers and newborns exist, which need to be addressed. Current evidence suggests that mothers with symptomatic COVID-19 infection are at increased risk of severe illness during pregnancy, with a higher need for respiratory support and premature deliveries. Neonates born to mothers with COVID-19 are at increased risk of needing intensive care; however, most newborns do well after birth. As new mutant variants arise, we need to be cautious while proactively understanding any new evolving patterns. All leading health authorities strongly recommend COVID-19 vaccination before or during pregnancy to reduce the risk of maternal morbidities and benefit from passing antibodies to newborns prenatally and via breastmilk. Additionally, there are racial, ethnic, and socioeconomic disparities in outcomes and vaccination coverage for pregnant women. This article summarizes the rapidly evolving evidence for the last 1.5 years and aims to help health care professionals care for mothers with COVID-19 and their newborns. KEY POINTS: · COVID-19 in pregnancy can cause perinatal morbidities.. · Breastfeeding and breast milk are safe for newborns.. · COVID-19 vaccination reduces the risk for morbidities..

Histopathological and immunological characteristics of placentas infected with chikungunya virus

Although vertical transmission of CHIKV has been reported, little is known about the role of placenta in the transmission of this virus and the effects of infection on the maternal-fetal interface. In this work we investigated five placentas from pregnant women who became infected during the gestational period. Four formalin-fixed paraffin-embedded samples of placenta (cases 1-4) were positive for CHIKV by RT-PCR. One (case 5) had no positive test of placenta, but had positive RT-PCR for CHIKV in the serum of the mother and the baby, confirming vertical transmission. The placentas were analyzed regarding histopathological and immunological aspects. The main histopathological changes were: deciduitis, villous edema, deposits, villous necrosis, dystrophic calcification, thrombosis and stem vessel obliteration. In infected placentas we noted increase of cells (CD8+ and CD163+) and pro- (IFN-γ and TNF-α) and anti-inflammatory (TGF-β and IL-10) cytokines compared to control placentas. Moreover, CHIKV antigen was detected in decidual cell, trophoblastic cells, stroma villi, Hofbauer cells, and endothelial cells. In conclusion, CHIKV infection seems to disrupt placental homeostasis leading to histopathological alterations in addition to increase in cellularity and cytokines overproduction, evidencing an altered and harmful environment to the pregnant woman and fetus.

Diffuse and Localized SARS-CoV-2 Placentitis: Prevalence and Pathogenesis of an Uncommon Complication of COVID-19 Infection During Pregnancy

Coronavirus disease 2019 (COVID-19) infection in pregnancy has been associated with preterm delivery and preeclampsia. A less frequent and underrecognized complication is extensive placental infection which is associated with high rates of perinatal morbidity and mortality. The frequency, early pathogenesis, and range of lesions associated with this infection are poorly understood. We conducted a population-based study of placental pathology from all mothers with COVID-19 (n=271) over an 18-month period delivering within our health system. The overall prevalence of diffuse severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) placentitis, as defined by typical histology and immunohistochemical (IHC) staining for SARS-CoV-2 spike protein, was 14.8/1000, but increased to 59/1000 in preterm births. We also identified 3 cases with isolated small foci of localized SARS-CoV-2 placentitis, characterized by focal perivillous fibrin and intervillositis, which illustrate the early pathogenesis and suggest that infection may be contained in some cases. Two other placental lesions were more common in mothers with COVID-19, high-grade maternal vascular malperfusion in preterm deliveries and high-grade chronic villitis at term (5/5 cases tested of the latter were negative by IHC for SARS-CoV-2). Additional investigation of diffuse and localized SARS-CoV-2 placentitis by IHC showed loss of BCL-2, C4d staining in surrounding villi, and an early neutrophil-predominant intervillous infiltrate that later became dominated by monocyte-macrophages. We propose a model of focal infection of syncytiotrophoblast by virally infected maternal leukocytes leading to loss of BCL-2 and apoptosis. Infection is then either contained by surrounding fibrinoid (localized) or initiates waves of aponecrosis and immune activation that spread throughout the villous parenchyma (diffuse).

Placental pathology in sudden intrauterine death (SIUD) in SARS-CoV-2-positive oligosymptomatic women

Background

Pregnant women are also susceptible to SARS-CoV-2. Although an infection of the placenta may be rare, pregnancy may occasionally be affected by intrauterine failure. The knowledge of placental morphology on sudden intrauterine demise is still limited.

Methods

Fetal and placental tissue of two cases of sudden intrauterine death in the second trimester were analysed morphologically and by immunohistochemistry. One case was evaluated by RT-PCR.

Results

Both mothers were tested positive for the Alpha variant of SARS-CoV-2 but were oligosymptomatic for COVID-19. Unexpected sudden intrauterine death (SIUD) occurred at 15 + 2 and 27 + 3 weeks of gestation. One fetus demonstrated an intrauterine growth restriction. No malformations nor inflammatory changes were observed in either fetus on autopsy. In contrast to the placentas, the fetal tissue was negative for SARS-CoV-2 on immunohistochemical and RT-PCR analyses. Macroscopically, the placentas showed an increased consistency with a white, reticular cutting surface covering about 95% of the whole placenta. Only very focal histiocytic chronic intervillositis was noted histologically. Massive perivillous fibrin deposits with extensive necroses of the villous trophoblast were present in more than 90% of the placental tissue. Immunohistochemical staining was strong and diffusely positive for SARS-CoV-2 in the villous trophoblast and rarely within the villous stromal cells. Placental SARS-CoV-2 infection was confirmed by RT-PCR.

Conclusion

Sudden intrauterine death may occur in mothers who are oligosymptomatic for COVID-19. Acute placental failure is responsible for SIUD, demonstrated by massive perivillous fibrin deposits and extensive necroses of the villous trophoblast with SARS-CoV-2-positivity based on immunohistochemical staining and RT-PCR. Detailed histopathological examination of placental and fetal tissue is mandatory to verify SARS-CoV-2 and to evaluate the pathogenesis and functionality of this disease.

SARS-COV2 placentitis and pregnancy outcome: A multicentre experience during the Alpha and early Delta waves of coronavirus pandemic in England

BACKGROUND

Pregnant women with SARS-CoV-2 infection experience higher rates of stillbirth and preterm birth. A unique pattern of chronic histiocytic intervillositis (CHI) and/or massive perivillous fibrin deposition (MPFD) has emerged, coined as SARS-CoV-2 placentitis.

METHODS

The aim of this study was to describe a cohort of placentas diagnosed with SARS-CoV-2 placentitis during October 2020-March 2021. Cases with a histological diagnosis of SARS-CoV-2 placentitis and confirmatory immunohistochemistry were reported. Maternal demographic data, pregnancy outcomes and placental findings were collected.

FINDINGS

59 mothers delivered 61 infants with SARS-CoV-2 placentitis. The gestational age ranged from 19 to 41 weeks with most cases (78.6%) being third trimester. 30 infants (49.1%) were stillborn or late miscarriages. Obese mothers had higher rates of pregnancy loss when compared with those with a BMI <30 [67% (10/15) versus 41% (14/34)]. 47/59 (79^.7%) mothers had a positive SARS-CoV-2 PCR test either at the time of labour or in the months before, of which 12 (25^.5%) were reported to be asymptomatic. Ten reported only CHI, two cases showed MPFD only and in 48 placentas both CHI and MPFD was described.

INTERPRETATION

SARS-CoV2 placentitis is a distinct entity associated with increased risk of pregnancy loss, particularly in the third trimester. Women can be completely asymptomatic and still experience severe placentitis. Unlike 'classical' MPFD, placentas with SARS-CoV-2 are generally normal in size with adequate fetoplacental weight ratios. Further work should establish the significance of the timing of maternal SARS-CoV-2 infection and placentitis, the significance of SARS-CoV2 variants, and rates of vertical transmission associated with this pattern of placental inflammation.

FUNDING

There was not funding associated with this study.

Inflammatory responses in the placenta upon SARS-CoV-2 infection late in pregnancy

The effect of SARS-CoV-2 infection on placental function is not well understood. Analysis of placentas from women who tested positive at delivery showed SARS-CoV-2 genomic and subgenomic RNA in 22 out of 52 placentas. Placentas from two mothers with symptomatic COVID-19 whose pregnancies resulted in adverse outcomes for the fetuses contained high levels of viral Alpha variant RNA. The RNA was localized to the trophoblasts that cover the fetal chorionic villi in direct contact with maternal blood. The intervillous spaces and villi were infiltrated with maternal macrophages and T cells. Transcriptome analysis showed an increased expression of chemokines and pathways associated with viral infection and inflammation. Infection of placental cultures with live SARS-CoV-2 and spike protein-pseudotyped lentivirus showed infection of syncytiotrophoblast and, in rare cases, endothelial cells mediated by ACE2 and Neuropilin-1. Viruses with Alpha, Beta, and Delta variant spikes infected the placental cultures at significantly greater levels.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Placental Infection Is Associated With Massive Perivillous Fibrin Deposition at the Maternal-Fetal Interface: A Preliminary Study

We observed an increased frequency of massive perivillous fibrin deposition (MPFD) during the second coronavirus disease 2019 (COVID-19) pandemic wave dominated by the Alpha variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). MPFD associated with 100% reverse transcription polymerase chain reaction (RT-PCR) positivity for SARS-CoV-2 and detection by immunohistochemistry. The Alpha variant was identified in all placentas with MPFD that could be sequenced.

Intrauteriner Fruchttod bei massiver SARS-CoV-2-assoziierter („severe acute respiratory syndrome coronavirus 2“) plazentarer maternaler Malperfusion im Rahmen einer SARS-CoV-2-Plazentitis

Wir berichten über die Befunde einer Plazenta der 31. Schwangerschaftswoche bei intrauterinem Fruchttod (IUFT) mit ungewöhnlich ausgeprägter maternaler Malperfusion und chronisch-histiozytärer Intervillositis im Sinn einer SARS-CoV-2(„severe acute respiratory syndrome coronavirus 2“)-Plazentitis. Mikrobiologisch sowie mittels Realtime-PCR wurde SARS-CoV-2- und B‑beta-Coronavirus-spezifische RNA am Plazenta‑, Nabelschnur- und Eihautgewebe nachgewiesen. Die bei SARS-CoV-2-Infektion inzwischen wiederholt beschriebene maternale Malperfusion ist in der vorliegenden Ausprägung Ausprägung im Rahmen einer schweren SARS-CoV-2-Plazentitis ungewöhnlich. Es betont die Notwendigkeit einer maternalen Thromboembolieprophylaxe.

Stillbirth after COVID-19 in Unvaccinated Mothers Can Result from SARS-CoV-2 Placentitis, Placental Insufficiency, and Hypoxic Ischemic Fetal Demise, Not Direct Fetal Infection: Potential Role of Maternal Vaccination in Pregnancy

Stillbirth is a recently recognized complication of COVID-19 in pregnant women. Other congenitally transmitted infections from viruses, bacteria and parasites can cause stillbirth by infecting fetal organs following transplacental transmission of the agent from the maternal bloodstream. However, recent research on pregnant women with COVID-19 having stillbirths indicates that there is another mechanism of stillbirth that can occur in placentas infected with SARS-CoV-2. In these cases, viral infection of the placenta results in SARS-CoV-2 placentitis, a combination of concurrent destructive findings that include increased fibrin deposition which typically reaches the level of massive perivillous fibrin deposition, chronic histiocytic intervillositis and trophoblast necrosis. These three pathological lesions, in some cases together with placental hemorrhage, thrombohematomas and villitis, result in severe and diffuse placental parenchymal destruction. This pathology can involve greater than one-half of the placental volume, averaging 77% in the largest study of 68 cases, effectively rendering the placenta incapable of performing its function of oxygenating the fetus. This destructive placental process can lead to stillbirth and neonatal death via malperfusion and placental insufficiency which is independent of fetal infection. Fetal autopsies show no evidence that direct infection of fetal organs is contributory. Because all mothers examined have been unvaccinated, maternal vaccination may prevent viremia and consequent placental infection.

The risk of intrauterine exposure to SARS-CoV-2 in female COVID-19 patients: A comprehensive review

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a new type of coronavirus that has caused fatal infectious diseases and global spread. This novel coronavirus attacks target cells through the interaction of spike protein and angiotensin‐converting enzyme II (ACE2), leading to different clinical symptoms. However, for a successful pregnancy, a well‐established in‐uterine environment includes a specific immune environment, and multi‐interactions between specific cell types are prerequisites. The immune‐related changes in patients infected with novel coronavirus could interfere with the immune microenvironment in the uterus, leading to fetal loss. We first reviewed the intrauterine environment in the normal development process and the possible pregnancy outcome in the infection state. Then, we summarized the immune response induced by SARS‐CoV‐2 in patients and analyzed the changes in ACE2 expression in the female reproductive system. Finally, the present observational evidence of infection in pregnant women was also reviewed.

Placental Tissue Destruction and Insufficiency from COVID-19 Causes Stillbirth and Neonatal Death from Hypoxic-Ischemic Injury: A Study of 68 Cases with SARS-CoV-2 Placentitis from 12 Countries

CONTEXT.—

Perinatal death is an increasingly important problem as the COVID-19 pandemic continues, but the mechanism of death has been unclear.

OBJECTIVE.—

To evaluate the role of the placenta in causing stillbirth and neonatal death following maternal infection with COVID-19 and confirmed placental positivity for SARS-CoV-2.

DESIGN.—

Case-based retrospective clinico-pathological analysis by a multinational group of 44 perinatal specialists from 12 countries of placental and autopsy pathology findings from 64 stillborns and 4 neonatal deaths having placentas testing positive for SARS-CoV-2 following delivery to mothers with COVID-19.

RESULTS.—

All 68 placentas had increased fibrin deposition and villous trophoblast necrosis and 66 had chronic histiocytic intervillositis, the three findings constituting SARS-CoV-2 placentitis. Sixty-three placentas had massive perivillous fibrin deposition. Severe destructive placental disease from SARS-CoV-2 placentitis averaged 77.7% tissue involvement. Other findings included multiple intervillous thrombi (37%; 25/68) and chronic villitis (32%; 22/68). The majority (19, 63%) of the 30 autopsies revealed no significant fetal abnormalities except for intrauterine hypoxia and asphyxia. Among all 68 cases, SARS-CoV-2 was detected from a body specimen in 16 of 28 cases tested, most frequently from nasopharyngeal swabs. Four autopsied stillborns had SARS-CoV-2 identified in internal organs.

CONCLUSIONS.—

The pathology abnormalities composing SARS-CoV-2 placentitis cause widespread and severe placental destruction resulting in placental malperfusion and insufficiency. In these cases, intrauterine and perinatal death likely results directly from placental insufficiency and fetal hypoxic-ischemic injury. There was no evidence that SARS-CoV-2 involvement of the fetus had a role in causing these deaths.

Intrauterine Fetal Demise After Uncomplicated COVID-19: What Can We Learn from the Case?

Background: SARS-CoV-2 infection in pregnant women can lead to placental damage and transplacental infection transfer, and intrauterine fetal demise is an unpredictable event. Case study: A 32-year-old patient in her 38th week of pregnancy reported loss of fetal movements. She overcame mild COVID-19 with positive PCR test 22 days before. A histology of the placenta showed deposition of intervillous fibrinoid, lympho-histiocytic infiltration, scant neutrophils, clumping of villi, and extant infarctions. Immunohistochemistry identified focal SARS-CoV-2 nucleocapsid and spike protein in the syncytiotrophoblast and isolated in situ hybridization of the virus’ RNA. Low ACE2 and TMPRSS2 contrasted with strong basigin/CD147 and PDL-1 positivity in the trophoblast. An autopsy of the fetus showed no morphological abnormalities except for lung interstitial infiltrate, with prevalent CD8-positive T-lymphocytes and B-lymphocytes. Immunohistochemistry and in situ hybridization proved the presence of countless dispersed SARS-CoV-2-infected epithelial and endothelial cells in the lung tissue. The potential virus-receptor protein ACE2, TMPRSS2, and CD147 expression was too low to be detected. Conclusion: Over three weeks’ persistence of trophoblast viral infection lead to extensive intervillous fibrinoid depositions and placental infarctions. High CD147 expression might serve as the dominant receptor for the virus, and PDL-1 could limit maternal immunity in placental tissue virus clearance. The presented case indicates that the SARS-CoV-2 infection-induced changes in the placenta lead to ischemia and consecutive demise of the fetus. The infection of the fetus was without significant impact on its death. This rare complication of pregnancy can appear independently to the severity of COVID-19’s clinical course in the pregnant mother.