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

Placental Drug Delivery to Treat Pre-Eclampsia and Fetal Growth Restriction

Pre-eclampsia and fetal growth restriction (FGR) continue to cause unacceptably high levels of morbidity and mortality, despite significant pharmaceutical and technological advances in other disease areas. The recent pandemic has also impacted obstetric care, as COVID-19 infection increases the risk of poor pregnancy outcomes. This review explores the reasons why it lacks effective drug treatments for the placental dysfunction that underlies many common obstetric conditions and describes how nanomedicines and targeted drug delivery approaches may provide the solution to the current drug drought. The ever-increasing range of biocompatible nanoparticle formulations available is now making it possible to selectively deliver drugs to uterine and placental tissues and dramatically limit fetal drug transfer. Formulations that are refractory to placental uptake offer the possibility of retaining drugs within the maternal circulation, allowing pregnant individuals to take medicines previously considered too harmful to the developing baby. Liposomes, ionizable lipid nanoparticles, polymeric nanoparticles, and adenoviral vectors have all been used to create efficacious drug delivery systems for use in pregnancy, although each approach offers distinct advantages and limitations. It is imperative that recent advances continue to be built upon and that there is an overdue investment of intellectual and financial capital in this field.

Epidemiology and Clinical Features of COVID-19 among 4,015 Neonates in Iran: Results of the National Study from the Iranian Maternal and Neonatal Network

OBJECTIVE

 The coronavirus disease 2019 (COVID-19) pandemic had a significant impact on pregnant women and neonates in Iran. This retrospective study describes the national experience among neonates having suspected and confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection following hospital admission to examine the epidemiology, demographic, and clinical features.

STUDY DESIGN

 All nationwide cases of suspected and confirmed neonatal SARS-CoV-2 infection were drawn from the Iranian Maternal and Neonatal Network (IMaN) between February 2020 and February 2021. IMaN registers demographic, maternal, and neonatal health data throughout Iran. Statistical analysis of demographic, epidemiological, and clinical data were performed.

RESULTS

 There were 4,015 liveborn neonates having suspected or confirmed SARS-CoV-2 infection that fulfilled the study inclusion criteria identified in the IMaN registry from 187 hospitals throughout Iran. There were 1,392 (34.6%) neonates that were preterm, including 304 (7.6%) less than 32 weeks' gestation. Among the 2,567 newborns admitted to the hospital immediately after birth, the most common clinical problems were respiratory distress (1,095 cases; 42.6%), sepsis-like syndrome (355; 13.8%), and cyanosis (300 cases; 11.6%). Of 683 neonates transferred from another hospital, the most frequent problems were respiratory distress (388; 56.8%), sepsis-like syndrome (152; 22.2%), and cyanosis (134; 19.6%). Among 765 neonates discharged home after birth and subsequently admitted to the hospital, sepsis-like syndrome (244 cases; 31.8%), fever (210; 27.4%), and respiratory distress (185; 24.1%) were most frequent. A total of 2,331 (58%) of neonates required respiratory care, with 2,044 surviving and 287 having a neonatal death. Approximately 55% of surviving neonates received respiratory support, compared with 97% of neonates who expired. Laboratory abnormalities included elevations of white blood cell count, creatine phosphokinase, liver enzymes, and C-reactive protein.

CONCLUSION

 This report adds the national experience of Iran to the list of reports from multiple countries describing their experience with COVID-19 in neonates, demonstrating that newborns are not exempt from COVID-19-morbidity and mortality.

KEY POINTS

· Most common clinical problem was respiratory distress.. · Sepsis-like syndrome was also frequently present.. · A total of 58% of all neonates required respiratory care..

Offspring cardiometabolic outcomes and postnatal growth trajectories after exposure to maternal SARS-CoV-2 infection

OBJECTIVE

The objective of this study is to determine whether in utero exposure to SARS-CoV-2 is associated with increased risk for a cardiometabolic diagnosis by 18 months of age.

METHODS

This retrospective electronic health record (EHR)-based cohort study included the live-born offspring of all individuals who delivered during the COVID-19 pandemic (April 1, 2020-December 31, 2021) at eight hospitals in Massachusetts. Offspring exposure was defined as a positive maternal SARS-CoV-2 polymerase chain reaction test during pregnancy. The primary outcome was presence of an ICD-10 code for a cardiometabolic disorder in offspring EHR by 18 months. Weight-, length-, and BMI-for-age z scores were calculated and compared at 6-month intervals from birth to 18 months.

RESULTS

A total of 29,510 offspring (1599 exposed and 27,911 unexposed) were included. By 18 months, 6.7% of exposed and 4.4% of unexposed offspring had received a cardiometabolic diagnosis (crude odds ratio [OR] 1.47 [95% CI: 1.10 to 1.94], p = 0.007; adjusted OR 1.38 [1.06 to 1.77], p = 0.01). Exposed offspring had a significantly greater mean BMI-for-age z score versus unexposed offspring at 6 months (z score difference 0.19 [95% CI: 0.10 to 0.29], p < 0.001; adjusted difference 0.04 [-0.06 to 0.13], p = 0.4).

CONCLUSIONS

Exposure to maternal SARS-CoV-2 infection was associated with an increased risk of receiving a cardiometabolic diagnosis by 18 months preceded by greater BMI-for-age at 6 months.

Perinatal arterial ischemic stroke: how informative is the placenta?

Neuroplacentology is an expanding field of interest that addresses the placental influence on fetal and neonatal brain lesions and on further neurodevelopment. The objective of this study was to clarify the link between placental pathology and perinatal arterial ischemic stroke (PAIS). Prior publications have reported different types of perinatal stroke with diverse methodologies precluding firm conclusions. We report here the histological placental findings in a series of 16 neonates with radiologically confirmed PAIS. Findings were grouped into 3 categories of lesions: (1) inflammation, (2) placental and fetal hypoxic lesions, and (3) placentas with a high birthweight/placenta weight ratio. Matched control placentas were compared to the pathological placentas when feasible. The eight term singleton placentas were compared to a series of 20 placentas from a highly controlled amniotic membrane donation program; in three twin pregnancies, the placental portions from the affected twin and unaffected co-twin were compared. Slightly more than half (9/16, 56%) had histopathological features belonging to more than one category, a feature shared by the singleton control placentas (13/20, 65%). More severe and extensive lesions were however observed in the pathological placentas. One case occurring in the context of SARS-CoV-2 placentitis further expands the spectrum of COVID-related perinatal disease. Our study supports the assumption that PAIS can result from various combinations and interplay of maternal and fetal factors and confirms the value of placenta examination. Yet, placental findings must be interpreted with caution given their prevalence in well-designed controls.

Placental inflammation in a fetal demise of a SARS-CoV-2-asymptomatic, COVID-19-unvaccinated pregnant woman: a case-report

BACKGROUND

Intrauterine fetal demise is a recognized complication of coronavirus disease 2019 in pregnant women and is associated with histopathological placental lesions. The pathological mechanism and virus-induced immune response in the placenta are not fully understood. A detailed description of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced inflammation in the placenta during fetal demise is crucial for improved clinical management.

CASE PRESENTATION

We report the case of a 27-week gestation SARS-CoV-2-asymptomatic unvaccinated pregnant woman without comorbidities or other risk factors for negative pregnancy outcomes with a diagnosis of intrauterine fetal demise. Histopathological findings corresponded to patterns of subacute inflammation throughout the anatomic compartments of the placenta, showing severe chorioamnionitis, chronic villitis and deciduitis, accompanied by maternal and fetal vascular malperfusion. Our immunohistochemistry results revealed infiltration of CD68+ macrophages, CD56+ Natural Killer cells and scarce CD8+ T cytotoxic lymphocytes at the site of placental inflammation, with the SARS-CoV-2 nucleocapsid located in stromal cells of the chorion and chorionic villi, and in decidual cells.

CONCLUSION

This case describes novel histopathological lesions of inflammation with infiltration of plasma cells, neutrophils, macrophages, and natural killer cells associated with malperfusion in the placenta of a SARS-CoV-2-infected asymptomatic woman with intrauterine fetal demise. A better understanding of the inflammatory effects exerted by SARS-CoV-2 in the placenta will enable strategies for better clinical management of pregnant women unvaccinated for SARS-CoV-2 to avoid fatal fetal outcomes during future transmission waves.

Intrauterine fetal death in a COVID positive pregnant woman

SARS-CoV-2 disease mechanisms are not yet fully understood, especially in cases affecting pregnant women. In fact, although they suffer from the same symptoms as non-pregnant women, they are more susceptible to-adverse outcomes of COVID-19 as well as pregnancy complications leading to stillbirth, premature rupture of membrane, or intrauterine fetal demise (IUFD). The consequences on pregnancy are not clearly correlated with the severity of the infection. We present a case of fetal death in a 30-year-old woman with a confirmed SARS-CoV-2 infection without any other significant clinical or obstetric disorders. A histopathological examination of the placenta indicated massive and diffuse intervillar fibrinoid deposits associated with chronic histiocytic intervillositis that can be associated with SARS-CoV-2 placentitis. Given the high rates of SARS-CoV-2 infections in pregnancy, it is important to understand the factors that determine negative pregnancy outcomes, regardless of the severity of the patient's symptoms.

Characterizing Histopathologic Features in Pregnancies With Chronic Histiocytic Intervillositis Using Computerized Image Analysis

CONTEXT.—

Chronic histiocytic intervillositis (CHI) is a rare condition characterized by maternal immune cell infiltration into the human placenta. CHI is strongly associated with fetal growth restriction, miscarriage, and stillbirth, and knowledge of its etiology, and consequently effective treatment, is limited. Currently, diagnosis is largely subjective and varies between centers, making comparison between studies challenging.

OBJECTIVE.—

To objectively quantify and interrelate inflammatory cells and fibrin in placentas with CHI compared with controls and determine how pathology may be altered in subsequent pregnancies following diagnosis. Macrophage phenotype was also investigated in untreated cases of CHI.

DESIGN.—

Computerized analysis was applied to immunohistochemically stained untreated (index) cases of CHI, subsequent pregnancies, and controls. Index placentas were additionally stained by immunofluorescence for M1 (CD80 and CD86) and M2 macrophage markers (CD163 and CD206).

RESULTS.—

Quantification revealed a median 32-fold increase in macrophage infiltration in index cases versus controls, with CHI recurring in 2 of 11 (18.2%) subsequent pregnancies. A total of 4 of 14 placentas (28.6%) with a diagnosis of CHI did not exhibit infiltration above controls. Macrophages in index pregnancies strongly expressed CD163. There was no significant difference in fibrin deposition between index cases and controls, although subsequent pregnancies displayed a 2-fold decrease compared with index pregnancies. CD3+ T cells were significantly elevated in index pregnancies; however, they returned to normal levels in subsequent pregnancies.

CONCLUSIONS.—

In CHI, intervillous macrophages expressed CD163, possibly representing an attempt to resolve inflammation. Computerized analysis of inflammation in CHI may be useful in determining how treatment affects recurrence, and alongside pathologist expertise in grading lesion severity.

Effects of SARS-Cov-2 mRNA vaccine on placental histopathology: Comparison of a population of uncomplicated COVID-19 positive pregnant women

1.

INTRODUCTION

This study investigates the impact of SARS-CoV-2 infection on placental histopathology in pregnant women, comparing outcomes between vaccinated and non-vaccinated individuals. Despite known adverse pregnancy outcomes linked to SARS-CoV-2 infection, the specific effects on the placenta remain unclear. Although vaccination has demonstrated a substantial reduction in infection severity, its impact on placental health requires more insight. 2.

METHODS

Between March 2021 and July 2022, 387 COVID-19-positive women were admitted for delivery. Of these, 98 with non-severe symptoms were analyzed: 35 vaccinated during pregnancy, and 63 non-vaccinated. Two independent pathologists evaluated all placental specimens. 3.

RESULTS

The only differing obstetrical characteristic between groups was the mode of delivery (p 0.047), lacking clinical implications. Over 85% of placentas exhibited microscopic abnormalities, predominantly maternal vascular supply disorders (vaccinated 89.1%; unvaccinated 85.5%). Comparing vaccinated and unvaccinated groups revealed statistically significant differences, notably in increased focal perivillous fibrin deposits (IFPFD) [17.1% vs. 33.3% (p 0.04)] and avascular fibrotic villi (AFV) [0% vs. 11.1% (p 0.04)]. Binomial logistic regression confirmed the vaccine's protective role against IFPFD (aOR 0.36; 95%CI 013-0.99) and AVF (aOR 0.06, 95% CI 0.003-0.98). A sub-analysis in vaccinated women showed a positive correlation between the timing of the first dose and IFPFD presence (p 0.018). 4.

DISCUSSION

The lower incidence of maternal and fetal vascular malperfusion placental features in vaccinated women, coupled with the timing correlation, supports the vaccine's protective effect on placental tissue in COVID-19-infected pregnant patients. Notably, no side effects were reported post-vaccination, emphasizing the vaccine's safety and advocating for its secure administration in pregnant populations.

COVID-19 vaccination protects infected pregnant women from developing SARS-CoV-2 placentitis and decreases the risk for stillbirth

INTRODUCTION

The impact of COVID-19 infection in pregnant women remained unclear for a long time. Previous research showed that SARS-CoV-2 virus is able to infect the placenta, potentially causing significant lesions leading to placental insufficiency. The impact of maternal vaccination status on the prevalence of SARS-CoV-2 placentitis remains unclear. We characterized placental lesions in SARS-CoV-2 infected pregnant women and studied the impact of vaccination on placental involvement.

METHODS

We retrospectively studied 180 placentas sent to the Department of Pathology in UZ Leuven or AZ Turnhout between January 2020 and August 2022, from non-vaccinated and vaccinated mothers suffering a SARS-CoV-2 proven infection during pregnancy. All reports and hematoxylin-eosin stained sections were revised by two pathologists to determine the presence of histopathological lesions that have been described in SARS-CoV-2 infection. SARS-CoV-2 immunostainings were available for a subgroup of 109 placentas. We gathered clinical data: date of delivery, date of positive serologic test result, vaccination status, SARS-CoV-2 variant and outcome of the pregnancy.

RESULTS

Of the 180 placentas, 37,2% showed histopathological lesions and in 12,8% an immunohistochemically proven SARS-CoV-2 placentitis was present. SARS-CoV-2 immunohistochemical positivity was only seen in non-vaccinated mothers. The risk of fetal demise was more than 5 times higher for non-vaccinated mothers and their placentas showed significantly more syncytiotrophoblast necrosis and chronic histiocytic intervillositis compared to vaccinated mothers (both p < 0,001).

DISCUSSION

Maternal vaccination was associated with a reduced risk of SARS-CoV-2 placentitis and stillbirth. This study provides new evidence of the protective effect of vaccination on the placenta.

Health of singleton neonates in Switzerland through time and crises: a cross-sectional study at the population level, 2007-2022

BACKGROUND

Being exposed to crises during pregnancy can affect maternal health through stress exposure, which can in return impact neonatal health. We investigated temporal trends in neonatal outcomes in Switzerland between 2007 and 2022 and their variations depending on exposure to the economic crisis of 2008, the flu pandemic of 2009, heatwaves (2015 and 2018) and the COVID-19 pandemic.

METHODS

Using individual cross-sectional data encompassing all births occurring in Switzerland at the monthly level (2007-2022), we analysed changes in birth weight and in the rates of preterm birth (PTB) and stillbirth through time with generalized additive models. We assessed whether the intensity or length of crisis exposure was associated with variations in these outcomes. Furthermore, we explored effects of exposure depending on trimesters of pregnancy.

RESULTS

Over 1.2 million singleton births were included in our analyses. While birth weight and the rate of stillbirth have remained stable since 2007, the rate of PTB has declined by one percentage point. Exposure to the crises led to different results, but effect sizes were overall small. Exposure to COVID-19, irrespective of the pregnancy trimester, was associated with a higher birth weight (+12 grams [95% confidence interval (CI) 5.5 to 17.9 grams]). Being exposed to COVID-19 during the last trimester was associated with an increased risk of stillbirth (odds ratio 1.24 [95%CI 1.02 to 1.50]). Exposure to the 2008 economic crisis during pregnancy was not associated with any changes in neonatal health outcomes, while heatwave effect was difficult to interpret.

CONCLUSION

Overall, maternal and neonatal health demonstrated resilience to the economic crisis and to the COVID-19 pandemic in a high-income country like Switzerland. However, the effect of exposure to the COVID-19 pandemic is dual, and the negative impact of maternal infection on pregnancy is well-documented. Stress exposure and economic constraint may also have had adverse effects among the most vulnerable subgroups of Switzerland. To investigate better the impact of heatwave exposure on neonatal health, weekly or daily-level data is needed, instead of monthly-level data.

Association of placental histopathological findings with COVID-19 and its predictive factors

Objective

The aims of the study are to describe the association of coronavirus disease (COVID-19) with the abnormal histopathological findings in human placenta and to highlight the potential predictors of these histopathological findings.

Methods

A retrospective cohort study, held in two obstetric units from January 2021- 2022, 34 patients who were confirmed cases of COVID- 19 were followed up till the time of delivery as their placenta were sent for histopathology. Patients diagnosed with other viral infections, chorioamnionitis, or were known case of as pre-term or term pre labour rupture of membrans (PROM) were excluded as well as pre exisiting diabetes mellitus or pre-eclampsia. Data analysis were performed using STATA software version 16.

Result

Specific histopatological findings (fetal vascular malperfusion, maternal vascular malperfusion, inflammatory pathology and thrombotic finding) were significantly high among 13 (38.2%) of the study group who got infected earlier in pregnancy (P<0.001). The period between the diagnosis of COVID-19 and the delivery significantly increases the odds of the presence of pathological findings by 2.75 times for each week the patients getting infected earlier.

Conclusion

Association of abnormal placental histopathological findings with COVID-19 infection in pregnancy and the potential predictor for the occurrence of placental findings is the longer duration between the diagnosis of the infection and the delivery.

COVID-19 in pregnant women: a systematic review and meta-analysis on the risk and prevalence of pregnancy loss

BACKGROUND

Pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more likely to experience preterm birth and their neonates are more likely to be stillborn or admitted to a neonatal unit. The World Health Organization declared in May 2023 an end to the coronavirus disease 2019 (COVID-19) pandemic as a global health emergency. However, pregnant women are still becoming infected with SARS-CoV-2 and there is limited information available regarding the effect of SARS-CoV-2 infection in early pregnancy on pregnancy outcomes.

OBJECTIVE AND RATIONALE

We conducted this systematic review to determine the prevalence of early pregnancy loss in women with SARS-Cov-2 infection and compare the risk to pregnant women without SARS-CoV-2 infection.

SEARCH METHODS

Our systematic review is based on a prospectively registered protocol. The search of PregCov19 consortium was supplemented with an extra electronic search specifically on pregnancy loss in pregnant women infected with SARS-CoV-2 up to 10 March 2023 in PubMed, Google Scholar, and LitCovid. We included retrospective and prospective studies of pregnant women with SARS-CoV-2 infection, provided that they contained information on pregnancy losses in the first and/or second trimester. Primary outcome was miscarriage defined as a pregnancy loss before 20 weeks of gestation, however, studies that reported loss up to 22 or 24 weeks were also included. Additionally, we report on studies that defined the pregnancy loss to occur at the first and/or second trimester of pregnancy without specifying gestational age, and for second trimester miscarriage only when the study presented stillbirths and/or foetal losses separately from miscarriages. Data were stratified into first and second trimester. Secondary outcomes were ectopic pregnancy (any extra-uterine pregnancy), and termination of pregnancy. At least three researchers independently extracted the data and assessed study quality. We calculated odds ratios (OR) and risk differences (RDs) with corresponding 95% CI and pooled the data using random effects meta-analysis. To estimate risk prevalence, we performed meta-analysis on proportions. Heterogeneity was assessed by I2.

OUTCOMES

We included 120 studies comprising a total of 168 444 pregnant women with SARS-CoV-2 infection; of which 18 233 women were in their first or second trimester of pregnancy. Evidence level was considered to be of low to moderate certainty, mostly owing to selection bias. We did not find evidence of an association between SARS-CoV-2 infection and miscarriage (OR 1.10, 95% CI 0.81-1.48; I2 = 0.0%; RD 0.0012, 95% CI -0.0103 to 0.0127; I2 = 0%; 9 studies, 4439 women). Miscarriage occurred in 9.9% (95% CI 6.2-14.0%; I2 = 68%; 46 studies, 1797 women) of the women with SARS CoV-2 infection in their first trimester and in 1.2% (95% CI 0.3-2.4%; I2 = 34%; 33 studies; 3159 women) in the second trimester. The proportion of ectopic pregnancies in women with SARS-CoV-2 infection was 1.4% (95% CI 0.02-4.2%; I2 = 66%; 14 studies, 950 women). Termination of pregnancy occurred in 0.6% of the women (95% CI 0.01-1.6%; I2 = 79%; 39 studies; 1166 women).

WIDER IMPLICATIONS

Our study found no indication that SARS-CoV-2 infection in the first or second trimester increases the risk of miscarriages. To provide better risk estimates, well-designed studies are needed that include pregnant women with and without SARS-CoV-2 infection at conception and early pregnancy and consider the association of clinical manifestation and severity of SARS-CoV-2 infection with pregnancy loss, as well as potential confounding factors such as previous pregnancy loss. For clinical practice, pregnant women should still be advised to take precautions to avoid risk of SARS-CoV-2 exposure and receive SARS-CoV-2 vaccination.

Epidemiology of COVID-19 in Infants in the United States: Incidence, Severity, Fatality, and Variants of Concern

BACKGROUND

The clinical spectrum of infant COVID-19 ranges from asymptomatic infection to life-threatening illness, yet epidemiologic surveillance has been limited for infants.

METHODS

Using COVID-19 case data (restricted to reporting states) and national mortality data, we calculated incidence, hospitalization, mortality and case fatality rates through March 2022.

RESULTS

Reported incidence of COVID-19 was 64.1 new cases per 1000 infant years (95% CI: 63.3-64.9). We estimated that 594,012 infants tested positive for COVID-19 nationwide by March 31, 2022. Viral variant comparisons revealed that incidence was 7× higher during the Omicron (January-March 2022) versus the pre-Delta period (June 2020-May 2021). The cumulative case hospitalization rate was 4.1% (95% CI: 4.0%-4.3%). For every 74 hospitalized infants, one infant death occurred, but overall COVID-19-related infant case fatality was low, with 7.0 deaths per 10,000 cases (95% CI: 5.6-8.7). Nationwide, 333 COVID-19 infant deaths were reported. Only 13 infant deaths (3.9%) were the result of usually lethal congenital anomalies. The majority of infant decedents were non-White (28.2% Black, 26.1% Hispanic, 8.1% Asian, Indigenous or multiracial).

CONCLUSIONS

More than half a million US infants contracted COVID-19 by March 2022. Longitudinal assessment of long-term infant SARS-CoV-2 infection sequelae remains a critical research gap. Extremely low infant vaccination rates (<5%), waning adult immunity and continued viral exposure risks suggest that infant COVID-19 will remain a persistent public health problem. Our study underscores the need to increase vaccination rates for mothers and infants, decrease viral exposure risks and improve health equity.

Planning for the future of maternal immunization: Building on lessons learned from the COVID-19 pandemic

As the worldwide COVID-19 pandemic unfolded, the clinical and public health community raced to understand SARS-CoV-2 infection and develop life-saving vaccines. Pregnant persons were disproportionately impacted, experiencing more severe illness and adverse pregnancy outcomes. And yet, when COVID-19 vaccines became available in late 2020, safety and efficacy data were not available to inform their use during pregnancy because pregnant persons were excluded from pre-authorization clinical trials. Concerns about vaccine safety during pregnancy and misinformation linking vaccination and infertility circulated widely, creating a lack of vaccine confidence. Many pregnant people initially chose not to get vaccinated, and while vaccination rates rose after safety and effectiveness data became available, COVID-19 vaccine acceptance was suboptimal and varied across racial and ethnic distribution of the pregnant population. The COVID-19 pandemic experience provided valuable insights that can inform current and future approaches to maternal vaccination against.

COVID-19 and abnormal uterine bleeding: potential associations and mechanisms

The impact of COVID-19 on menstruation has received a high level of public and media interest. Despite this, uncertainty exists about the advice that women and people who menstruate should receive in relation to the expected impact of SARS-CoV-2 infection, long COVID or COVID-19 vaccination on menstruation. Furthermore, the mechanisms leading to these reported menstrual changes are poorly understood. This review evaluates the published literature on COVID-19 and its impact on menstrual bleeding, discussing the strengths and limitations of these studies. We present evidence consistent with SARS-CoV-2 infection and long COVID having an association with changes in menstrual bleeding parameters and that the impact of COVID vaccination on menstruation appears less significant. An overview of menstrual physiology and known causes of abnormal uterine bleeding (AUB) is provided before discussing potential mechanisms which may underpin the menstrual disturbance reported with COVID-19, highlighting areas for future scientific study. Finally, consideration is given to the effect that menstruation may have on COVID-19, including the impact of the ovarian sex hormones on acute COVID-19 severity and susceptibility and reported variation in long COVID symptoms across the menstrual cycle. Understanding the current evidence and addressing gaps in our knowledge in this area are essential to inform public health policy, direct the treatment of menstrual disturbance and facilitate development of new therapies, which may reduce the severity of COVID-19 and improve quality of life for those experiencing long COVID.

Whole transcriptome profiling of placental pathobiology in SARS-CoV-2 pregnancies identifies placental dysfunction signatures

Objectives

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus infection in pregnancy is associated with higher incidence of placental dysfunction, referred to by a few studies as a 'preeclampsia-like syndrome'. However, the mechanisms underpinning SARS-CoV-2-induced placental malfunction are still unclear. Here, we investigated whether the transcriptional architecture of the placenta is altered in response to SARS-CoV-2 infection.

Methods

We utilised whole-transcriptome, digital spatial profiling, to examine gene expression patterns in placental tissues from participants who contracted SARS-CoV-2 in the third trimester of their pregnancy (n = 7) and those collected prior to the start of the coronavirus disease 2019 (COVID-19) pandemic (n = 9).

Results

Through comprehensive spatial transcriptomic analyses of the trophoblast and villous core stromal cell subpopulations in the placenta, we identified SARS-CoV-2 to promote signatures associated with hypoxia and placental dysfunction. Notably, genes associated with vasodilation (NOS3), oxidative stress (GDF15, CRH) and preeclampsia (FLT1, EGFR, KISS1, PAPPA2) were enriched with SARS-CoV-2. Pathways related to increased nutrient uptake, vascular tension, hypertension and inflammation were also enriched in SARS-CoV-2 samples compared to uninfected controls.

Conclusions

Our findings demonstrate the utility of spatially resolved transcriptomic analysis in defining the underlying pathogenic mechanisms of SARS-CoV-2 in pregnancy, particularly its role in placental dysfunction. Furthermore, this study highlights the significance of digital spatial profiling in mapping the intricate crosstalk between trophoblasts and villous core stromal cells, thus shedding light on pathways associated with placental dysfunction in pregnancies with SARS-CoV-2 infection.

Clinical course and management of COVID-19 in the era of widespread population immunity

The clinical implications of COVID-19 have changed since SARS-CoV-2 first emerged in humans. The current high levels of population immunity, due to prior infection and/or vaccination, have been associated with a vastly decreased overall risk of severe disease. Some people, particularly those with immunocompromising conditions, remain at risk for severe outcomes. Through the course of the pandemic, variants with somewhat different symptom profiles from the original SARS-CoV-2 virus have emerged. The management of COVID-19 has also changed since 2020, with the increasing availability of evidence-based treatments in two main classes: antivirals and immunomodulators. Selecting the appropriate treatment(s) for patients with COVID-19 requires a deep understanding of the evidence and an awareness of the limitations of applying data that have been largely based on immune-naive populations to patients today who most likely have vaccine-derived and/or infection-derived immunity. In this Review, we provide a summary of the clinical manifestations and approaches to caring for adult patients with COVID-19 in the era of vaccine availability and the dominance of the Omicron subvariants, with a focus on the management of COVID-19 in different patient groups, including immunocompromised, pregnant, vaccinated and unvaccinated patients.

Maternal COVID-19 infection and intrauterine fetal death: Impact on the placenta and fetus

BACKGROUND

Placental damage due to viral infections increases risk of adverse perinatal outcomes. Histopathologic examination of placenta can provide information regarding association between infection and outcome. There is paucity of data describing placental pathology with respect to intrauterine fetal death (IUFD) in pregnant mothers affected with COVID-19.

METHODS

4 fetuses and 10 placentas, including one twin placenta from 9 women with history of IUFD and SARS-CoV-2 infection underwent evaluation. These findings were contrasted with 3 fetuses and 21 gestational age matched placentas from non-infected women with history of IUFD.

RESULTS

Extensive gross placental lesions, mixture of histologic features (maternal/ fetal vascular malperfusion) and isolated cases of massive perivillous fibrin depositon and chronic intervillositis were observed in COVID-IUFD group. There were no distinguishing histologic findings when compared to control. Three fetuses showed signs of intraventricular/intraparenchymal hemorrhage in autopsy.

CONCLUSION

These findings demonstrate that IUFD does not correspond with maternal symptoms and lacks distinctive lesion. However, there was significant placental damage which developed rapidly. These results show that SARS-CoV-2 infection results in rapid placental deterioration and fetal death. This information can be used to educate infected mothers and remind medical professionals, value of monitoring placental function especially following diagnosis of infection.

Placental pathology in a large (Swedish) cohort of SARS-CoV-2 infected mothers

INTRODUCTION

SARS-CoV-2 placentitis is associated with placental destruction and insufficiency and can affect perinatal outcome. The aim of the current study was to contribute with increased knowledge regarding placental histology in maternal SARS-CoV-2 infection during the pregnancy, as well as the correlation to the severity of maternal SARS-CoV-2 infection.

MATERIAL AND METHODS

This retrospective observational study included 116 women who had a verified SARS-CoV-2 infection during pregnancy and gave birth between April 2020 and February 2022 in the Stockholm region, Sweden. Placental tissue was evaluated regarding several histopathological parameters, amongst them detection of the triad of characteristics of placental SARS-CoV-2 infection: chronic histiocytic intervillositis, fibrin deposition and villous trophoblast necrosis, and immunohistochemistry for ORF-3 protein expression was used for confirmation. Medical records were reviewed for maternal characteristics and neonatal outcome.

RESULTS

SARS-CoV-2 placentitis was present in one-fifth of the examined placentas admitted to the institute due to maternal SARS-CoV-2 infection, out of which 86,4 % were delivered by acute caesarian section (ACS), all on fetal indication, and one pregnancy ended in stillbirth. Half of the cases without placentitis were delivered by ACS, out of which 50 % were on fetal indication. There was a clear tendency of a shorter time gap between confirmed maternal SARS-CoV-2 infection and delivery in the placentitis group.

DISCUSSION

The presence of SARS-CoV-2 placentitis does not seem to correlate with maternal factors or the severity of infection. It does correlate with development of placental dysfunction of acute/subacute onset and is often manifested as reduced fetal movements.

Intrinsic factors behind long COVID: III. Persistence of SARS-CoV-2 and its components

Considerable research has been done in investigating SARS-CoV-2 infection, its characteristics, and host immune response. However, debate is still ongoing over the emergence of post-acute sequelae of SARS-CoV-2 infection (PASC). A multitude of long-lasting symptoms have been reported several weeks after the primary acute SARS-CoV-2 infection that resemble several other viral infections. Thousands of research articles have described various post-COVID-19 conditions. Yet, the evidence around these ongoing health problems, the reasons behind them, and their molecular underpinnings are scarce. These persistent symptoms are also known as long COVID-19. The persistence of SARS-CoV-2 and/or its components in host tissues can lead to long COVID. For example, the presence of viral nucleocapsid protein and RNA was detected in the skin, appendix, and breast tissues of some long COVID patients. The persistence of viral RNA was reported in multiple anatomic sites, including non-respiratory tissues such as the adrenal gland, ocular tissue, small intestine, lymph nodes, myocardium, and sciatic nerve. Distinctive viral spike sequence variants were also found in non-respiratory tissues. Interestingly, prolonged detection of viral subgenomic RNA was observed across all tissues, sometimes in multiple tissues of the same patient, which likely reflects recent but defective viral replication. Moreover, the persistence of SARS-CoV-2 RNA was noticed throughout the brain at autopsy, as late as 230 days following symptom onset among unvaccinated patients who died of severe infection. Here, we review the persistence of SARS-CoV-2 and its components as an intrinsic factor behind long COVID. We also highlight the immunological consequences of this viral persistence.

Neonatal outcomes of maternal prenatal coronavirus infection

The coronavirus disease 2019 (COVID-19) pandemic has led to significant changes in life and healthcare all over the world. Pregnant women and their newborns require extra attention due to the increased risk of adverse outcomes. Adverse pregnancy outcomes include intensive care unit (ICU) admission, pulmonary, cardiac, and renal impairment leading to mortality. Immaturity and variations of the neonatal immune system may be advantageous in responding to the virus. Neonates are at risk of vertical transmission and in-utero infection. Impaired intrauterine growth, prematurity, vertical transmission, and neonatal ICU admission are the most concerning issues. Data on maternal and neonatal outcomes should be interpreted cautiously due to study designs, patient characteristics, clinical variables, the effects of variants, and vaccination beyond the pandemic. Cesarean section, immediate separation of mother-infant dyads, isolation of neonates, and avoidance of breast milk were performed to reduce transmission risk at the beginning of the pandemic in the era of insufficient knowledge. Vertical transmission was found to be low with favorable short-term outcomes. Serious fetal and neonatal outcomes are not expected, according to growing evidence. Long-term effects may be associated with fetal programming. Knowledge and lessons from COVID-19 will be helpful for the next pandemic if it occurs. IMPACT: Prenatal infection with SARS-CoV-2 is associated with adverse maternal and neonatal outcomes. Our review includes the effects of COVID-19 on the fetus and neonates, transmission routes, placental effects, fetal and neonatal outcomes, and long-term effects on neonates. There is a growing body of data and evidence about the COVID-19 pandemic. Knowledge and lessons from the pandemic will be helpful for the next pandemic if it happens.

Non-Viral RNA Delivery During Pregnancy: Opportunities and Challenges

During pregnancy, the risk of maternal and fetal adversities increases due to physiological changes, genetic predispositions, environmental factors, and infections. Unfortunately, treatment options are severely limited because many essential interventions are unsafe, inaccessible, or lacking in sufficient scientific data to support their use. One potential solution to this challenge may lie in emerging RNA therapeutics for gene therapy, protein replacement, maternal vaccination, fetal gene editing, and other prenatal treatment applications. In this review, the current landscape of RNA platforms and non-viral RNA delivery technologies that are under active development for administration during pregnancy is explored. Advancements of pregnancy-specific RNA drugs against SARS-CoV-2, Zika, influenza, preeclampsia, and for in-utero gene editing are discussed. Finally, this study highlights bottlenecks that are impeding translation efforts of RNA therapies, including the lack of accurate cell-based and animal models of human pregnancy and concerns related to toxicity and immunogenicity during pregnancy. Overcoming these challenges will facilitate the rapid development of this new class of pregnancy-safe drugs.

Researching COVID to enhance recovery (RECOVER) pregnancy study: Rationale, objectives and design

IMPORTANCE

Pregnancy induces unique physiologic changes to the immune response and hormonal changes leading to plausible differences in the risk of developing post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID. Exposure to SARS-CoV-2 during pregnancy may also have long-term ramifications for exposed offspring, and it is critical to evaluate the health outcomes of exposed children. The National Institutes of Health (NIH) Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC aims to evaluate the long-term sequelae of SARS-CoV-2 infection in various populations. RECOVER-Pregnancy was designed specifically to address long-term outcomes in maternal-child dyads.

METHODS

RECOVER-Pregnancy cohort is a combined prospective and retrospective cohort that proposes to enroll 2,300 individuals with a pregnancy during the COVID-19 pandemic and their offspring exposed and unexposed in utero, including single and multiple gestations. Enrollment will occur both in person at 27 sites through the Eunice Kennedy Shriver National Institutes of Health Maternal-Fetal Medicine Units Network and remotely through national recruitment by the study team at the University of California San Francisco (UCSF). Adults with and without SARS-CoV-2 infection during pregnancy are eligible for enrollment in the pregnancy cohort and will follow the protocol for RECOVER-Adult including validated screening tools, laboratory analyses and symptom questionnaires followed by more in-depth phenotyping of PASC on a subset of the overall cohort. Offspring exposed and unexposed in utero to SARS-CoV-2 maternal infection will undergo screening tests for neurodevelopment and other health outcomes at 12, 18, 24, 36 and 48 months of age. Blood specimens will be collected at 24 months of age for SARS-CoV-2 antibody testing, storage and anticipated later analyses proposed by RECOVER and other investigators.

DISCUSSION

RECOVER-Pregnancy will address whether having SARS-CoV-2 during pregnancy modifies the risk factors, prevalence, and phenotype of PASC. The pregnancy cohort will also establish whether there are increased risks of adverse long-term outcomes among children exposed in utero.

CLINICAL TRIALS.GOV IDENTIFIER

Clinical Trial Registration: http://www.clinicaltrials.gov. Unique identifier: NCT05172011.

COVID-19 during pregnancy could potentially affect placental function

OBJECTIVE

COVID-19 is an ongoing pandemic and has been extensively studied. However, the effects of COVID-19 during pregnancy, particularly on placental function, have not been verified. In this study, we used blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) to evaluate whether COVID-19 incidence during pregnancy has any lasting effects with respect to placental oxygenation.

METHODS

This is a case-control study, in which eight cases of singleton pregnancies before 30 weeks gestation with COVID-19 mothers were included. Placental oxygenation was evaluated using BOLD-MRI after 32 weeks of gestation. BOLD-MRI was consecutively performed under normoxia (21% O2), hyperoxia (100% O2), and normoxia for 4 min each. Individual placental time-activity curves were evaluated to calculate the peak score (peakΔR2*) and the time from the start of maternal oxygen administration to the time of peakΔR2* (time to peakΔR2*). Eighteen COVID-19-free normal pregnancies from a previous study were used as the control group.

RESULTS

No significant differences were found between the two groups regarding maternal background, number of days of delivery, birth weight, and placental weight. The parameter peakΔR2* was significantly decreased in the COVID-19 group (8 ± 3 vs. 5 ± 1, p < .001); however, there was no significant difference in time to peakΔR2* (458 ± 74 s vs. 471 ± 33 s, p = .644).

CONCLUSIONS

In this study, BOLD-MRI was used to evaluate placental oxygenation during pregnancy in COVID-19-affected patients. COVID-19 during pregnancy decreased placental oxygenation even post-illness, but had no effect on fetal growth; further investigation of the possible effects of COVID-19 on the fetus and mother is warranted.

SARS-CoV-2 infection as cause of in-utero fetal death: regional multicenter cohort study

OBJECTIVE

Placental infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to placental insufficiency and in-utero fetal death (IUFD). The objective of this study was to confirm and quantify the extent to which fetoplacental infection with SARS-CoV-2 is a cause of fetal death.

METHODS

This was a multicenter retrospective cohort study of fetal deaths that underwent postmortem examination between January 2020 and January 2022 in three fetal pathology units in Paris, France. All cases of IUFD and termination of pregnancy (TOP) occurring in 31 maternity hospitals in the Paris region undergo detailed placental pathological examination in these units. Databases were searched for cases of IUFD and TOP. Cases with fetal malformation or cytogenetic abnormality were excluded to avoid bias. We included cases of IUFD with a placental or undetermined cause and cases of TOP in the context of severe intrauterine growth restriction (IUGR). Placentas were sent to a single virology unit for reverse-transcription polymerase chain reaction (RT-PCR) testing by a single laboratory technician blinded to the initial postmortem examination report. Our primary endpoint was the proportion of positive placental SARS-CoV-2 RT-PCR tests in the cohort.

RESULTS

Among 147 722 deliveries occurring over 2 years, 788 postmortem examinations for IUFD and TOP for severe IUGR were recorded, of which 462 (58.6%) were included. A total of 13/462 (2.8%) placentas tested positive for SARS-CoV-2 by RT-PCR. Wild-type virus and alpha and delta variants were identified. All positive cases had histological lesions consistent with placental dysfunction. There was a strong correlation between SARS-CoV-2 placentitis and the presence of chronic intervillositis and/or massive fibrin deposits in the placenta. When both lesion types were present, the specificity and negative predictive value for the diagnosis of placental SARS-CoV-2 infection were 0.99 (95% CI, 0.98-1.00) and 0.96 (95% CI, 0.94-0.98), respectively.

CONCLUSIONS

At the height of the SARS-CoV-2 pandemic, the cause of more than half of fetal deaths in the Paris area was determined by postmortem analysis to be of placental or undetermined origin. Of these cases, 2.8% were due to placental SARS-CoV-2 infection with a specific pattern of histological involvement. This study highlights the need for SARS-CoV-2 screening in stillbirth assessment. The impact of vaccination coverage remains to be established. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

SARS-CoV-2 Infection in Late Pregnancy and Childbirth from the Perspective of Perinatal Pathology

This review focuses on SARS-CoV-2 infection in placental and fetal tissues. Viremia is rare in infected pregnant women, and the virus is seldom amplified from placental tissues. Definite and probable placental infection requires the demonstration of viral RNA or proteins using in situ hybridization (ISH) and immunohistochemistry (IHC). Small subsets (1.0-7.9%, median 2.8%) of placentas of SARS-CoV-2-positive women showed definite infection accompanied by a characteristic histopathology named SARS-CoV-2 placentitis (SP). The conventionally accepted histopathological criteria for SP include the triad of intervillositis, perivillous fibrin deposition, and trophoblast necrosis. SP was shown to be independent of the clinical severity of the infection, but associated with stillbirth in cases where destructive lesions affecting more than 75% of the placental tissue resulted in placental insufficiency and severe fetal hypoxic-ischemic injury. An association between maternal thrombophilia and SP was shown in a subset of cases, suggesting a synergy of the infection and deficient coagulation cascade as one of the mechanisms of the pathologic accumulation of fibrin in affected placentas. The virus was amplified from fetal tissues in approximately 40% of SP cases, but definite fetal involvement demonstrated using ISH or IHC is exceptionally rare. The placental pathology in SARS-CoV-2-positive women also includes chronic lesions associated with placental malperfusion in the absence of definite or probable placental infection. The direct viral causation of the vascular malperfusion of the placenta in COVID-19 is debatable, and common predispositions (hypertension, diabetes, and obesity) may play a role.

Clinical and serological findings in pregnant women and newborns: patterns of coronavirus disease 2019 placental histopathology

OBJECTIVE

The objective of this study was to evaluate the correlation between clinical and serological findings of pregnant women and newborns with patterns of histopathologic changes of the placenta diagnosed with coronavirus disease 2019.

METHODS

A prospective descriptive study was conducted with pregnant women who were positive for SARS-CoV-2 by reverse transcription polymerase chain reaction or serology (IgG and IgM). Clinical analyses were performed using ELISA to detect anti-SARS-CoV-2 IgG and IgA antibodies using the S1 spike protein domain with the Euroimmun kit. Histopathologic analyses of placentas were performed by two expert pathologists.

RESULTS

Maternal SARS-CoV-2 infection was associated with increased neonatal hospital length of stay (p=0.03), increased preterm birth (p=0.04), and Apgar score<7 at 1st min (p=0.00) and 5th min (p=0.02). Pregnant women with positive IgG and/or IgA at delivery had a higher incidence of placental histopathologic changes in addition to a greater likelihood of having an IgG-positive fetus (p<0.0001). Placentas with positive reverse transcription polymerase chain reaction for SARS-CoV-2 had a higher incidence of histopathologic changes such as maternal vascular hypoperfusion changes (p=0.00).

CONCLUSION

Maternal SARS-CoV-2 infection was associated with adverse perinatal outcomes. Pregnant women with positive IgG at delivery had a higher incidence of placental histopathologic changes. Placentas with positive reverse transcription polymerase chain reaction for SARS-CoV-2 had a higher incidence of histopathologic changes such as maternal vascular hypoperfusion.

IgG antibody levels against the SARS-CoV-2 spike protein in mother-child dyads after COVID-19 vaccination

PURPOSE

We aimed to assess IgG antibodies against the SARS-CoV-2 spike protein (anti-SARS-CoV-2 S IgG) in vaccinated mothers and their infants at delivery and 2-3 months of age.

METHODS

We conducted a prospective study on mothers who received at least one dose of the COVID-19 vaccine (Pfizer-BNT162b2, Moderna mRNA-1273, or Oxford-AstraZeneca ChAdOx1-S) during pregnancy and on their infants. The baseline was at the time of delivery (n = 93), and the end of follow-up was 2 to 3 months post-partum (n = 53). Serum anti-SARS-CoV-2 S IgG titers and ACE2 binding inhibition levels were quantified by immunoassays.

RESULTS

Mothers and infants had high anti-SARS-CoV-2 S IgG titers against the B.1 lineage at birth. However, while antibody titers were maintained at 2-3 months post-partum in mothers, they decreased significantly in infants (p < 0.001). Positive and significant correlations were found between anti-SARS-CoV-2 S IgG titers and ACE2-binding inhibition levels in mothers and infants at birth and 2-3 months post-partum (r > 0.8, p < 0.001). Anti-S antibodies were also quantified for the Omicron variant at 2-3 months post-partum. The antibody titers against Omicron were significantly lower in mothers and infants than those against B.1 (p < 0.001). Again, a positive correlation was observed for Omicron between IgG titers and ACE2-binding inhibition both in mothers (r = 0.818, p < 0.001) and infants (r = 0.386, p < 0.005). Previous SARS-CoV-2 infection and COVID-19 vaccination near delivery positively impacted anti-SARS-CoV-2 S IgG levels.

CONCLUSIONS

COVID-19 mRNA vaccines induce high anti-SARS-CoV-2 S titers in pregnant women, which can inhibit the binding of ACE2 to protein S and are efficiently transferred to the fetus. However, there was a rapid decrease in antibody levels at 2 to 3 months post-partum, particularly in infants.

Hypoxia modifies levels of the SARS-CoV-2 cell entry proteins, angiotensin-converting enzyme 2, and furin in fetal human brain endothelial cells

BACKGROUND

It is not known whether human fetal brain endothelial cells that form the blood-brain barrier express angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin, which are SARS-CoV-2 cell entry proteins. Moreover, it is unclear whether hypoxia, commonly observed during severe maternal COVID-19, can modify their level of expression. We hypothesized that human fetal brain endothelial cells isolated from early- and midpregnancy brain microvessels express angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin. Furthermore, we hypothesized that hypoxia modifies their expression levels in a gestational age- and time-of-exposure-dependent manner.

OBJECTIVE

This study aimed to investigate whether early- and midpregnancy human fetal brain endothelial cells express angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin SARS-CoV-2-associated cell entry proteins and to determine the effects of hypoxia on angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin expression levels in human fetal brain endothelial cells.

STUDY DESIGN

This was a prospective study where human fetal brain endothelial cells isolated from early-pregnancy (12.4±0.7 weeks of gestation) and midpregnancy (17.9±0.5 weeks of gestation) fetal brain microvessels (6 per group) were exposed to different oxygen tensions (20%, 5%, and 1% oxygen) for 6, 24, and 48 hours. Angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin messenger RNA and protein levels and localization were assessed using quantitative polymerase chain reaction, Western blot testing, and immunofluorescence.

RESULTS

Angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin co-localize with the endothelial cell marker von Willebrand factor in human fetal brain endothelial cells isolated from early pregnancy and midpregnancy. In early pregnancy, TMPRSS2 messenger RNA expression was decreased by 5% oxygen compared with 20% oxygen after 6 hours of exposure (P<.05). In midpregnancy, 5% oxygen down-regulated ACE2 messenger RNA compared with 20% oxygen after 24 hours (P<.05). Furin messenger RNA expression was decreased under 5% and 1% oxygen compared with 20% oxygen (P<.05) after 24 hours. In midpregnancy, angiotensin-converting enzyme 2 protein levels were decreased under 5% and 1% oxygen (P<.001) after 24 hours. In contrast, furin protein levels were increased under 1% oxygen compared with 20% oxygen after 24 hours (P<.05). At 48 hours, 1% oxygen increased angiotensin-converting enzyme 2 protein levels compared with 20% oxygen (P<.01).

CONCLUSION

Hypoxia modifies the expression of selected SARS-CoV-2 cell entry proteins in human fetal brain endothelial cells in a gestational age- and time-of-exposure-dependent manner. As severe COVID-19 may lead to maternal hypoxia, an altered expression of these proteins in the developing human blood-brain barrier could potentially lead to altered SARS-CoV-2 brain invasion and neurologic sequelae in neonates born to pregnancies complicated by SARS-CoV-2 infection.

Histological Alterations in Placentas of Pregnant Women with SARS-CoV-2 Infection: A Single-Center Case Series

This study aimed to investigate the histopathological changes associated with SARS-CoV-2 infection in placentas. A case series of anatomopathological analysis was conducted on the placentas of pregnant women with SARS-CoV-2 who delivered between March and December 2020 at Santo Amaro Hospital (HSA) in Salvador, Brazil. Out of the 29 placentas examined, the median weight was 423.0 (IQR: 385.0-521.0) g. Among them, 58.3% (n = 14) had inadequate weight relative to the newborn's weight. The histopathological findings revealed that 86.2% (n = 25) of the placentas had poorly defined lobes, and the fetal and maternal surface color was normal in 89.7% (n = 26) and 93.1% (n = 27), respectively. Additionally, 51.7% (n = 15) of the umbilical cords displayed hypercoiling. The most frequent microscopic finding was infarction, present in 35.3% (n = 6) of the cases, followed by 11.8% (n = 2) for each of chorioamnionitis, chronic villitis, focal perivillositis, and laminar necrosis. Analysis of the umbilical cords identified 23.5% (n = 4) cases of intervillous thrombosis, while amnion analysis showed 13.8% (n = 4) cases of squamous metaplasia. Extraplacental membrane examination revealed fibrin deposition in 93.1% (n = 27) of the cases, necrosis in 62.0% (n = 18), calcifications in 51.7% (n = 15), cysts in 37.9% (n = 11), neutrophilic exudate in 17.2% (n = 5), thrombosis in 13.7% (n = 4), and delayed placental maturation in 6.9% (n = 2). All analyzed placentas exhibited histopathological changes, primarily vascular and inflammatory, which indicate SARS-CoV-2 infection in term pregnancies. These alterations could be associated with impaired placental function, fetal growth restriction, preeclampsia, and prematurity. However, further prospective studies are required to validate the type, prevalence, and prognosis of each of these changes.

Burden of stillbirths among women vaccinated with COVID-19 vaccines: A systematic review and meta-analysis

OBJECTIVE

To estimate the global burden of stillbirths among pregnant women with the COVID-19 vaccination.

DATA SOURCE

In this systematic review and meta-analysis, a literature search was carried out in PubMed, Cochrane and Scopus until February 4, 2023, with language restriction (English).

STUDY SELECTION

Title-abstract screening followed by full text review was done independently by two authors, based on the research question, "What is the prevalence of stillbirths among the pregnant women vaccinated with COVID-19 vaccines?"

DATA EXTRACTION

Two authors independently extracted the relevant data from every study. The third author resolved the conflicts. This study was registered in PROSPERO and followed the PRISMA guidelines.

DATA ANALYSIS

A Random effects model was applied to assess the pooled estimate of stillbirths. The I2 test was used to assess the heterogeneity of the articles included in the study. For checking the publication bias, the Doi plot and the contour-enhanced funnel plot were utilized.

RESULTS

The database systematic search yielded 168 articles; 11 of them were determined to be eligible for systematic review and 8 of them ended up being included for meta-analysis. The pooled prevalence of stillbirth in pregnant women vaccinated against COVID-19 infection was 0.00509 (5 per 1000 live births delivered by pregnant women vaccinated against COVID-19 (95% CI: 0.00003-0.01676). Statistically significant heterogeneity was reported across studies (I2 = 98%; p < 0.01).

CONCLUSIONS

The study concluded that vaccination against COVID-19 among pregnant women had a low stillbirth rate. It adds to the existing evidence that the COVID-19 vaccine is safe and can be taken during pregnancy.

A History of COVID-19 in Pregnancy: A Narrative Review

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread across the world causing a global pandemic. During a pandemic, it becomes increasing important to evaluate the effects on specific populations at risk. In this narrative review, we analyzed the literature regarding COVID-19 infection on the pregnant population as they are at increased risk of infection. COVID-19 did seem to significantly increase the risk of obstetric complications, specifically in underserved and marginalized populations. In general, COVID-19 rarely directly infected the fetus and placenta, apart from a very rare complication called COVID placentitis. In actuality, the mothers were at greatest direct risk due to COVID-19 infection. The most important takeaway from this pandemic is the prospective lesson and effect it had on social determinants of health. Women did not have safe access to antenatal care, leading to a plethora of indirect obstetric complications due to COVID-19. In conclusion, it was women who suffered from the pandemic, not the placenta nor the fetus. It is our duty as physicians to protect pregnant women, allowing the placenta to protect the fetus.

Viral persistence in children infected with SARS-CoV-2: current evidence and future research strategies

In this Personal View, we discuss current knowledge on SARS-CoV-2 RNA or antigen persistence in children infected with SARS-CoV-2. Based on the evidence that the virus can persist in adults, we have done a literature review and analysed studies that looked for SARS-CoV-2 RNA or antigens in children undergoing autopsy, biopsy, or surgery for either death from COVID-19 or multisystem inflammatory syndrome, or assessments for long COVID-19 or other conditions. Our analysis suggests that in children, independent from disease severity, SARS-CoV-2 can spread systemically and persist for weeks to months. We discuss what is known about the biological effects of viral persistence for other viral infections and highlight new scenarios for clinical, pharmacological, and basic research exploration. Such an approach will improve the understanding and management of post-viral syndromes.

Comparative Analysis of Hematological and Biochemical Changes in Neonates among Women with and without COVID-19 Infection during Pregnancy

The aim of this study is to evaluate the test results of neonates delivered by COVID-19-positive mothers during pregnancy with those of neonates born to unvaccinated mothers who are COVID-19-free. A cohort study was conducted on 367 pregnant women who gave birth at Premiere Hospital, Timisoara, Romania, between May 2021 and February 2022. Two groups were established: Group 1, with 167 pregnant women infected with COVID-19, and Group 2, with 200 pregnant women who were not affected by COVID-19 during pregnancy. Maternal laboratory examination did not exhibit significant variations except for platelet count. In neonatal blood tests, WBC had a significantly lower median value in the group born to COVID-19-free mothers. Neonatal anemia and leukocytosis showed slightly higher prevalence in Group 1, but the differences were not statistically significant. This study suggests that maternal COVID-19 infection during pregnancy does not have significant associations with most maternal and neonatal characteristics.

SARS-CoV-2 Infection in Unvaccinated High-Risk Pregnant Women in the Bronx, NY, USA Is Associated with Decreased Apgar Scores and Placental Villous Infarcts

Babies born to severe acute respiratory syndrome corona virus-2 (SARS-CoV-2)-infected mothers are at greater risk for perinatal morbidity and more likely to receive a neurodevelopmental diagnosis in the first year of life. However, the effect of maternal infection on placental function and neonatal outcomes varies depending upon the patient population. We set out to test our hypothesis that maternal SARS-CoV-2 infection in our underserved, socioeconomically disadvantaged, mostly unvaccinated, predominantly African American and Latina population in the Bronx, NY would have effects evident at birth. Under IRB approval, 56 SARS-CoV-2-positive patients infected during the "first wave" of the pandemic with alpha and beta strains of the virus, 48 patients infected during the "second wave" of the pandemic with delta and omicron strains and 61 negative third-trimester high-risk patients were randomly selected from Montefiore Medical Center (MMC), Bronx, NY. In addition, two positive cases from Yale New Haven Hospital, CT were included as controls. All 104 placentas delivered by SARS-CoV-2-positive mothers were uninfected by the virus, based on immunohistochemistry, in situ hybridization, and qPCR analysis. However, placental villous infarcts were significantly increased in first-wave cases compared to second-wave cases or negative controls. Significantly lower Apgar scores at 1 min and 5 min were observed in neonates born to infected mothers with severe symptoms. These findings suggest that even without entering the placenta, SARS-CoV-2 can affect various systemic pathways, culminating in altered placental development and function, which may adversely affect the fetus, especially in a high-risk patient population such as ours. These results underline the importance of vaccination among pregnant women, particularly in low-resource areas.

Impact of COVID-19 on pregnant women's health: Consequences in obstetrics two years after the pandemic

The pandemic linked to SARS-CoV-2 has profoundly disrupted the health systems and many studies have led to a better understanding of this virus, which is responsible for severe disease, particularly during pregnancy. Pregnancy is a risk factor for severe COVID-19. Term of pregnancy and vaccination status is the main risk factor in addition to classic comorbidities like general population. COVID-19 during pregnancy is responsible for more maternal death, stillbirth, pre-eclampsia spontaneous and induced prematurity. Vaccination is therefore strongly recommended for pregnant patients. In addition, the COVID-19 pandemic has highlighted a psychological and social dimension that should not be neglected in the management of a pregnant patient. Correlation between immunological changes and clinical impact are described in this review. Many conclusions can now be made and are summarized in this article in order to discuss possible future research.

A placental model of SARS-CoV-2 infection reveals ACE2-dependent susceptibility and differentiation impairment in syncytiotrophoblasts

SARS-CoV-2 infection causes COVID-19. Several clinical reports have linked COVID-19 during pregnancy to negative birth outcomes and placentitis. However, the pathophysiological mechanisms underpinning SARS-CoV-2 infection during placentation and early pregnancy are not clear. Here, to shed light on this, we used induced trophoblast stem cells to generate an in vitro early placenta infection model. We identified that syncytiotrophoblasts could be infected through angiotensin-converting enzyme 2 (ACE2). Using a co-culture model of vertical transmission, we confirmed the ability of the virus to infect syncytiotrophoblasts through a previous endometrial cell infection. We further demonstrated transcriptional changes in infected syncytiotrophoblasts that led to impairment of cellular processes, reduced secretion of HCG hormone and morphological changes vital for syncytiotrophoblast function. Furthermore, different antibody strategies and antiviral drugs restore these impairments. In summary, we have established a scalable and tractable platform to study early placental cell types and highlighted its use in studying strategies to protect the placenta.

Mpox (Monkeypox) in Pregnancy: Viral Clade Differences and Their Associations with Varying Obstetrical and Fetal Outcomes

In African countries where mpox (monkeypox) is endemic, infection is caused by two genetically related clades-Clade I (formerly Congo Basin), and Clade IIa (formerly West Africa), both of which are potentially life-threatening infections. Prior to the 2022-2023 global outbreak, mpox infections among pregnant women caused by Clade I were reported to have a 75% perinatal case fatality rate in the Democratic Republic of Congo, including the only documented case of placental infection and stillbirth from the Congenital Mpox Syndrome, and the Clade IIa mpox infection was associated with stillbirths in Nigeria. The 2022-2023 global mpox outbreak, caused by a genetically distinct strain, Clade IIb, has focused attention on the effects of mpox on pregnant women and fetal outcomes. There have been at least 58 cases of mpox infection occurring in pregnant women during the 2022-2023 outbreak. No confirmed cases of adverse perinatal outcome, including stillbirth, have been reported. The absence of perinatal morbidity and mortality from Clade IIb corresponds to the overall case fatality rate among non-pregnant women of <0.1%, as this clade has been demonstrated to produce a less-severe disease than the mpox Clade I or IIa variants. Thus, there are apparently important differences between mpox clades affecting pregnant women and perinatal outcomes.

Pregnancy, fetal, and neonatal outcomes after a first booster dose of covid-19 vaccine during pregnancy in Ontario, Canada: population based, retrospective cohort study

Objective

To assess risk of adverse pregnancy, fetal, and neonatal outcomes after a third dose (first booster dose) of covid-19 vaccine during pregnancy among individuals who had completed both doses of primary covid-19 vaccine series before pregnancy.

Design

Population based, retrospective cohort study.

Setting

Ontario, Canada, from 20 December 2021 to 31 August 2022.

Participants

Individuals were included if they were pregnant with an expected date of delivery from 20 December 2021 (start date of third dose eligibility for everyone ≥18 years) to 31 August 2022, who had completed the two doses of primary covid-19 messenger RNA vaccine series before pregnancy, and became eligible for a third dose (≥six months since dose two) before the end of pregnancy.

Main outcome measures

Pregnancy outcomes included hypertensive disorders of pregnancy, placental abruption, caesarean delivery, chorioamnionitis, and postpartum hemorrhage. Fetal and neonatal outcomes included stillbirth, preterm birth, admission to neonatal intensive care unit for >24 h, newborn 5 min Apgar score <7, and small-for-gestational age infant (<10th percentile). We estimated hazard ratios and 95% confidence intervals for study outcomes, treating dose three as a time varying exposure and adjusting for confounding using inverse probability weighting.

Results

Among 32 689 births, 18 491 (56.6%) were born to individuals who received a third covid-19 dose during pregnancy. Compared with eligible individuals who did not receive a third dose during pregnancy, no increased risks were associated with receiving a third covid-19 vaccine dose during pregnancy for placental abruption (adjusted hazard ratio 0.84 (95% confidence interval 0.70 to 1.02)), chorioamnionitis (0.67 (0.49 to 0.90)), postpartum haemorrhage (1.01 (0.89 to 1.16)), caesarean delivery (0.90 (0.87 to 0.94)), stillbirth (0.56 (0.39 to 0.81)), preterm birth (0.91 (0.84 to 0.99)), neonatal intensive care unit admission (0.96 (0.90 to 1.03)), 5 min Apgar score<7 (0.96 (0.82 to 1.14)), or small-for-gestational age infant (0.86 (0.79 to 0.93)).

Conclusion

Receipt of a third covid-19 vaccine dose during pregnancy was not associated with an increased risk of adverse pregnancy, fetal, or neonatal outcomes. These findings can help to inform evidence based decision making about the risks and benefits of covid-19 booster doses during pregnancy.

Morphological placental findings in women infected with SARS-CoV-2 according to trimester of pregnancy and severity of disease

INTRODUCTION

Placental morphology findings in SARS-CoV-2 infection are considered nonspecific, although the role of trimester and severity of infection are underreported. Therefore, we aimed to investigate abnormal placental morphology, according to these two criteria.

METHODS

This is an ancillary analysis of a prospective cohort study of pregnant women with suspected SARS-CoV-2 infection, managed in one maternity, from March 2020 to October 2021. Charting of clinical/obstetric history, trimester and severity of COVID-19 infection, and maternal/perinatal outcomes were done. Placental morphological findings were classified into maternal and fetal circulatory injury and acute/chronic inflammation. We further compared findings with women with suspected disease which tested negative for COVID-19. Diseases' trimester of infection and clinical severity guided the analysis of confirmed COVID-19 cases.

RESULTS

Ninety-one placental discs from 85 women were eligible as a COVID-19 group, and 42 discs from 41 women in negative COVID-19 group. SARS-CoV-2 infection occurred in 68.2% during third trimester, and 6.6% during first; 16.5% were asymptomatic, 61.5% non-severe and 22.0% severe symptomatic (two maternal deaths). Preterm birth occurred in 33.0% (one fetal death). Global maternal vascular malperfusion (MVM) were significant in COVID-19 group whether compared with negative COVID-19 tests group; however, fetal vascular malperfusion lesions and low-grade chronic villitis were not. Three placentas had COVID-19 placentitis. Decidual arteriopathy was associated with infection in first/mid trimester, and chorangiosis in asymptomatic infections.

DISCUSSION

Placental abnormalities after an infection by COVID-19 were more frequent after first/mid-trimester infections. Extensive placental lesions are rare, although they may be more common upon underlying medical conditions.

Analysis of placental pathology after COVID-19 by timing and severity of infection

BACKGROUND

COVID-19 during pregnancy can have serious effects on pregnancy outcomes. The placenta acts as an infection barrier to the fetus and may mediate adverse outcomes. Increased frequency of maternal vascular malperfusion has been detected in the placentas of patients with COVID-19 compared with controls, but little is known about how the timing and severity of infection affect placental pathology.

OBJECTIVE

This study aimed to examine the effects of SARS-CoV-2 infection on placental pathology, specifically whether the timing and severity of COVID-19 affect pathologic findings and associations with perinatal outcomes.

STUDY DESIGN

This was a descriptive retrospective cohort study of pregnant people diagnosed with COVID-19 who delivered between April 2020 and September 2021 at 3 university hospitals. Demographic, placental, delivery, and neonatal outcomes were collected through medical record review. The timing of SARS-CoV-2 infection was noted, and the severity of COVID-19 was categorized on the basis of the National Institutes of Health guidelines. The placentas of all patients with positive nasopharyngeal reverse transcription-polymerase chain reaction COVID-19 testing were sent for gross and microscopic histopathologic examinations at the time of delivery. Nonblinded pathologists categorized histopathologic lesions according to the Amsterdam criteria. Univariate linear regression and chi-square analyses were used to assess how the timing and severity of SARS-CoV-2 infection affected placental pathologic findings.

RESULTS

This study included 131 pregnant patients and 138 placentas, with most patients delivered at the University of California, Los Angeles (n=65), followed by the University of California, San Francisco (n=38) and Zuckerberg San Francisco General Hospital (n=28). Most patients were diagnosed with COVID-19 in the third trimester of pregnancy (69%), and most infections were mild (60%). There was no specific placental pathologic feature based on the timing or severity of COVID-19. There was a higher frequency of placental features associated with response to infection in the placentas from infections before 20 weeks of gestation than that from infections after 20 weeks of gestation (P=.001). There was no difference in maternal vascular malperfusion by the timing of infection; however, features of severe maternal vascular malperfusion were only found in the placentas of patients with SARS-CoV-2 infection in the second and third trimesters of pregnancy, not in the placentas of patients with COVID-19 in the first trimester of pregnancy.

CONCLUSION

Placentas from patients with COVID-19 showed no specific pathologic feature, regardless of the timing or severity of the disease. There was a higher proportion of placentas from patients with COVID-19-positive tests in earlier gestations with evidence of placental infection-associated features. Future studies should focus on understanding how these placental features in SARS-CoV-2 infections go on to affect pregnancy outcomes.

COVID-19 Vaccine Hesitancy among English-Speaking Pregnant Women Living in Rural Western United States

This mixed-method study investigated vaccine hesitancy among pregnant women living in rural western United States and their response to social media ads promoting COVID-19 vaccine uptake. Thirty pregnant or recently pregnant participants who live in rural zip codes in Washington, Oregon, California, and Idaho were interviewed between November 2022 and March 2023. Interviews were transcribed and coded, while the ad ratings were analyzed using linear mixed models. The study identified five main themes related to vaccine uptake, including perceived risk of COVID, sources of health information, vaccine hesitancy, and relationships with care providers. Participants rated ads most highly that used peer-based messengers and negative outcome-based content. Ads with faith-based and elder messengers were rated significantly lower than peer messengers (p = 0.04 and 0.001, respectively). An activation message was also rated significantly less favorably than negative outcome-based content (p = 0.001). Participants preferred evidence-based information and the ability to conduct their own research on vaccine safety and efficacy rather than being told to get vaccinated. Primary concerns of vaccine-hesitant respondents included the short amount of time the vaccine had been available and perceived lack of research on its safety during pregnancy. Our findings suggests that tailored messaging using peer-based messengers and negative outcome-based content can positively impact vaccine uptake among pregnant women living in rural areas of the Western United States.

Managing Labour in Women with COVID-19

Since first reported in December 2019 in Wuhan, China, COVID-19 caused by Severe Acute Respiratory Syndrome (SARS) Corona virus2 (SARS CoV-2) quickly spread to become a pandemic that has caused significant morbidity and mortality. The rapidity of the spread of the virus and the high mortality at the outset threatened to overwhelm health systems worldwide, and, indeed, this significantly impacted maternal health, especially since there was minimal experience to draw from. Experience with Covid 19 has grown exponentially as the unique needs of pregnant and labouring women with COVID-19 infection have become more evident. Managing COVID-19 parturients requires a multidisciplinary team consisting of anaesthesiologists, obstetricians, neonatologists, nursing staff, critical care staff, infectious disease and infection control experts. There should be a clear policy on triaging patients depending on the severity of their condition and the stage of labour. Those at high risk of respiratory failure should be managed in a tertiary referral centre with facilities for intensive care and assisted respiration. Staff and patients in delivery suites and operating rooms should be protected by enforcing infection protection principles such as offering dedicated rooms and theatres to SARS CoV-2 positive patients and using personal protective equipment. All hospital staff must be trained in infection control measures which should be updated regularly. Breastfeeding and care of the new-born must be part of the healthcare package offered to COVID-19 parturient mothers.

Identification of a unique intervillous cellular signature in chronic histiocytic intervillositis

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a rare histopathological lesion in the placenta characterized by an infiltrate of CD68⁺ cells in the intervillous space. CHI is associated with adverse pregnancy outcomes such as miscarriage, fetal growth restriction, and (late) intrauterine fetal death. The adverse pregnancy outcomes and a variable recurrence rate of 25-100% underline its clinical relevance. The pathophysiologic mechanism of CHI is unclear, but it appears to be immunologically driven. The aim of this study was to obtain a better understanding of the phenotype of the cellular infiltrate in CHI.

METHOD

We used imaging mass cytometry to achieve in-depth visualization of the intervillous maternal immune cells and investigated their spatial orientation in situ in relation to the fetal syncytiotrophoblast.

RESULTS

We found three phenotypically distinct CD68⁺HLA-DR⁺CD38⁺ cell clusters that were unique for CHI. Additionally, syncytiotrophoblast cells in the vicinity of these CD68⁺HLA-DR⁺CD38⁺ cells showed decreased expression of the immunosuppressive enzyme CD39.

DISCUSSION

The current results provide novel insight into the phenotype of CD68⁺ cells in CHI. The identification of unique CD68⁺ cell clusters will allow more detailed analysis of their function and could result in novel therapeutic targets for CHI.

The effects of COVID-19 on placental morphology

The impact of the COVID-19 infection, caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), during the pandemic has been considerably more severe in pregnant women than non-pregnant women. Therefore, a review detailing the morphological alterations and physiological changes associated with COVID-19 during pregnancy and the effect that these changes have on the feto-placental unit is of high priority. This knowledge is crucial for these mothers, their babies and clinicians to ensure a healthy life post-pandemic. Hence, we review the placental morphological changes due to COVID-19 to enhance the general understanding of how pregnant mothers, their placentas and unborn children may have been affected by this pandemic. Based on current literature, we deduced that COVID-19 pregnancies were oxygen deficient, which could further result in other pregnancy-related complications like preeclampsia and IUGR. Therefore, we present an up-to-date review of the COVID-19 pathophysiological implications on the placenta, covering the function of the placenta in COVID-19, the effects of this virus on the placenta, its functions and its link to other gestational complications. Furthermore, we highlight the possible effects of COVID-19 therapeutic interventions on pregnant mothers and their unborn children. Based on the literature, we strongly suggest that consistent surveillance for the mothers and infants from COVID-19 pregnancies be prioritised in the future. Though the pandemic is now in the past, its effects are long-term, necessitating the monitoring of clinical manifestations in the near future.

Late miscarriage and stillbirth in asymptomatic and symptomatic hospitalised pregnant women in Belgium during the first and second waves of COVID-19: a prospective nationwide population-based study

BACKGROUND

Stillbirth has been recognized as a possible complication of a SARS-CoV-2 infection during pregnancy, probably due to destructive placental lesions (SARS-CoV-2 placentitis). The aim of this work is to analyse stillbirth and late miscarriage cases in unvaccinated pregnant women infected with SARS-CoV-2 during the first two waves (wild-type period) in Belgium.

METHODS

Stillbirths and late miscarriages in our prospective observational nationwide registry of SARS-CoV-2 infected pregnant women (n = 982) were classified by three authors using a modified WHO-UMC classification system for standardized case causality assessment.

RESULTS

Our cohort included 982 hospitalised pregnant women infected with SARS-CoV-2, with 23 fetal demises (10 late miscarriages from 12 to 22 weeks of gestational age and 13 stillbirths). The stillbirth rate was 9.5‰ for singleton pregnancies and 83.3‰ for multiple pregnancies, which seems higher than for the background population (respectively 5.6‰ and 13.8‰). The agreement between assessors about the causal relationship with SARS-Cov-2 infection was fair (global weighted kappa value of 0.66). Among these demises, 17.4% (4/23) were "certainly" attributable to SARS-CoV-2 infection, 13.0% (3/23) "probably" and 30.4% (7/23) "possibly". Better agreement in the rating was noticed when pathological examination of the placenta and identification of the virus were available, underlining the importance of a thorough investigation in case of intra-uterine fetal demise.

CONCLUSIONS

SARS-CoV-2 causality assessment of late miscarriage and stillbirth cases in our Belgian nationwide case series has shown that half of the fetal losses could be attributable to SARS-CoV-2. We must consider in future epidemic emergencies to rigorously investigate cases of intra-uterine fetal demise and to store placental tissue and other material for future analyses.

Maternal SARS-CoV-2, Placental Changes and Brain Injury in 2 Neonates

Long-term neurodevelopmental sequelae are a potential concern in neonates following in utero exposure to severe acute respiratory syndrome coronavirus disease 2 (SARS-CoV-2). We report 2 neonates born to SARS-CoV-2 positive mothers, who displayed early-onset (day 1) seizures, acquired microcephaly, and significant developmental delay over time. Sequential MRI showed severe parenchymal atrophy and cystic encephalomalacia. At birth, neither infant was SARS-CoV-2 positive (nasopharyngeal swab, reverse transcription polymerase chain reaction), but both had detectable SARS-CoV-2 antibodies and increased blood inflammatory markers. Placentas from both mothers showed SARS-CoV-2-nucleocapsid protein and spike glycoprotein 1 in the syncytiotrophoblast, fetal vascular malperfusion, and significantly increased inflammatory and oxidative stress markers pyrin domain containing 1 protein, macrophage inflammatory protein 1 βη, stromal cell-derived factor 1, interleukin 13, and interleukin 10, whereas human chorionic gonadotropin was markedly decreased. One infant (case 1) experienced sudden unexpected infant death at 13 months of age. The deceased infant's brain showed evidence of SARS-CoV-2 by immunofluorescence, with colocalization of the nucleocapsid protein and spike glycoprotein around the nucleus as well as within the cytoplasm. The constellation of clinical findings, placental pathology, and immunohistochemical changes strongly suggests that second-trimester maternal SARS-CoV-2 infection with placentitis triggered an inflammatory response and oxidative stress injury to the fetoplacental unit that affected the fetal brain. The demonstration of SARS-CoV-2 in the deceased infant's brain also raises the possibility that SARS-CoV-2 infection of the fetal brain directly contributed to ongoing brain injury. In both infants, the neurologic findings at birth mimicked the presentation of hypoxic-ischemic encephalopathy of newborn and neurologic sequelae progressed well beyond the neonatal period.