Placental Pathology in Covid-19 Positive Mothers: Preliminary Findings

Trimester and severity of SARS-CoV-2 infection during pregnancy and risk of hypertensive disorders in pregnancy

OBJECTIVE

SARS-CoV-2 infection during pregnancy has been linked with an increased risk of hypertensive disorders of pregnancy (HDP). The aim of this study was to examine how both trimester and severity of SARS-CoV-2 infection impact HDP.

METHODS

We conducted a cohort study of SARS-CoV-2-infected individuals during pregnancy (n = 205) and examined the association between trimester and severity of infection with incidence of HDP using modified Poisson regression models to calculate risk ratios (RR) and 95% confidence intervals (CI). We stratified the analysis of trimester by severity to understand the role of timing of infection among those with similar symptomatology and also examined timing of infection as a continuous variable.

RESULTS

Compared to a reference cohort from 2018, SARS-CoV-2 infection did not largely increase the risk of HDP (RR: 1.17; CI:0.90, 1.51), but a non-statistically significant higher risk of preeclampsia was observed (RR: 1.33; CI:0.89, 1.98), in our small sample. Among the SARS-CoV-2 cohort, severity was linked with risk of HDP, with infections requiring hospitalization increasing the risk of HDP compared to asymptomatic/mild infections. Trimester of infection was not associated with risk of HDP, but a slight decline in the risk of HDP was observed with later gestational week of infection. Among patients with asymptomatic or mild symptoms, SARS-CoV-2 in the first trimester conferred a higher risk of HDP compared to the third trimester (RR: 1.70; CI:0.77, 3.77), although estimates were imprecise.

CONCLUSION

SARS-CoV-2 infection in early pregnancy may increase the risk of HDP compared to infection later in pregnancy.

Placenta a potential gateway of prenatal SARS-CoV-2 infection: A review

SARS-CoV-2, the causative agent of COVID-19, can infect various tissues in the body apart from the lungs. Although placental infection remains controversial, COVID-19-associated placental abnormalities have been reported worldwide. Therefore, COVID-19 poses a significant risk for fetal distress as well. Scientists are currently debating whether such distress results from direct viral induced assault or placental damage caused by the mother's immune response. The placenta develops different histopathological lesions in response to maternal SARS-CoV-2 infection. While some studies support both theories, the transmission rate through the placenta remains low. Therefore, a more in-depth study is necessary to determine the primary cause of maternal SARS-CoV-2-induced fetal distress. This comprehensive review is aimed to shed light on the possible reasons towards fetal distress among mothers with COVID-19. This review describes the various mechanisms of viral entry along with the mechanisms by which the virus could affect the placenta. Reported cases of placental abnormalities and fetal distress symptoms have been collated to provide an overview of the current state of knowledge on vertical transmission of COVID-19.

Enhancing the Diagnostic Accuracy of Placental Pathology by Using the Amsterdam Consensus Criteria

Background and objective Standardizing placental pathology diagnoses is crucial for improving diagnostic accuracy and clinical communication. The Amsterdam Consensus Criteria were developed to address inconsistencies in diagnosing significant placental pathologies. This study aimed to assess the application and effectiveness of the Amsterdam Consensus Criteria in diagnosing placental pathologies, with a focus on improving the reliability and precision of placental pathology reports. Methods A retrospective review of 100 consecutively archived placental pathology samples was performed at a tertiary care hospital. These samples, gathered from January through December 2021, were reassessed according to the Amsterdam criteria. The revised diagnoses were then compared with the original descriptive diagnoses. Results Significant changes were noted in all principal diagnoses, including maternal vascular malperfusion (MVM), fetal vascular malperfusion (FVM), chronic villitis of unknown etiology (VUE), and acute chorioamnionitis (ACA). This evaluation led to a recategorization of several cases. Frequently, parenchymal infarcts were reported without adequate information to ascertain their association with MVM. Additionally, there was a noticeable lack of understanding of FVM and VUE among pathologists. ACA was the condition most consistently documented. However, detailed grading and staging were often not included. Conclusions Our findings emphasize the need to use standardized diagnostic criteria, such as the Amsterdam criteria, to enhance diagnostic accuracy and facilitate communication between pathologists and clinicians. This will ultimately lead to improved patient care outcomes. It also underlines the necessity of continuous education and calibration for pathologists to mitigate interobserver variability. There is a demand to modify these criteria to ensure universal applicability and relevance in various clinical settings.

Impact of SARS-CoV-2 infection during pregnancy on the placenta and fetus

Pregnant people and their fetuses are vulnerable to adverse health outcomes from coronavirus 2019 disease (COVID-19) due to infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has been associated with higher rates of maternal mortality, preterm birth, and stillbirth. While SARS-CoV-2 infection of the placenta and vertical transmission is rare, this may be due to the typically longer time interval between maternal infection and testing of the placenta and neonate. Placental injury is evident in cases of SARS-CoV-2-associated stillbirth with massive perivillous fibrin deposition, chronic histiocytic intervillositis, and trophoblast necrosis. Maternal COVID-19 can also polarize fetal immunity, which may have long-term effects on neurodevelopment. Although the COVID-19 pandemic continues to evolve, the impact of emerging SARS-CoV-2 variants on placental and perinatal injury/mortality remains concerning for maternal and perinatal health. Here, we highlight the impact of COVID-19 on the placenta and fetus and remaining knowledge gaps.

Maternal COVID-19 exposure and placental characteristics

INTRODUCTION

The impact of COVID-19 on the placenta is poorly described, particularly among minority women.

MATERIALS AND METHODS

This is a retrospective case-control study. Micro- and macroscopic placental pathologic findings were compared for 15 COVID-19 positive and 36 negative mothers. Cases and controls were frequency matched on gestational age, race, maternal comorbidities, and delivery type. Data from the electronic medical record were supplemented with independent review of microscopic slides.

RESULTS

Placentas from cases and controls were similar except the median distance from the site of the cord insertion to the nearest disk margin was statistically significantly shorter among placentas from COVID-19 positive cases (3.5 versus 6.0 cm, p = 0.006). Case status was not associated with an increased risk of placental pathologies.

CONCLUSION

There are few pathologic differences between placentas of COVID-19 positive and negative mothers. Additional studies are needed to investigate the role of timing of infection.

Chronic villitis as a distinctive feature of placental injury in maternal SARS-CoV-2 infection

BACKGROUND

SARS-CoV-2 infection during pregnancy is associated with an increased risk for stillbirth, preeclampsia, and preterm birth. However, this does not seem to be caused by intrauterine fetal infection because vertical transmission is rarely reported. There is a paucity of data regarding the associated placental SARS-CoV-2 histopathology and their relationship with the timing and severity of infection.

OBJECTIVE

This study aimed to determine if maternal SARS-CoV-2 infection was associated with specific patterns of placental injury and if these findings differed by gestational age at time of infection or disease severity.

STUDY DESIGN

A retrospective cohort study was performed at the University of California San Diego between March 2020 and February 2021. Placentas from pregnancies with a positive SARS-CoV-2 test were matched with 2 sets of controls; 1 set was time-matched by delivery date and sent to pathology for routine clinical indications, and the other was chosen from a cohort of placentas previously collected for research purposes without clinical indications for pathologic examination before the SARS-CoV-2 outbreak. Placental pathologic lesions were defined based on standard criteria and included maternal and fetal vascular malperfusion and acute and chronic inflammatory lesions. A bivariate analysis was performed using the independent Student t test and Pearson chi-square test. A logistic regression was used to control for relevant covariates. Regions of SARS-CoV-2-associated villitis were further investigated using protein-based digital spatial profiling assays on the GeoMx platform, validated by immunohistochemistry, and compared with cases of infectious villitis and villitis of unknown etiology. Differential expression analysis was performed to identify protein expression differences between these groups of villitis.

RESULTS

We included 272 SARS-CoV-2 positive cases, 272 time-matched controls, and 272 historic controls. The mean age of SARS-CoV-2 affected subjects was 30.1±5.5 years and the majority were Hispanic (53.7%) and parous (65.7%). SARS-CoV-2 placentas demonstrated a higher frequency of the 4 major patterns of placental injury (all P<.001) than the historic controls. SARS-CoV-2 placentas also showed a higher frequency of chronic villitis and severe chronic villitis (P=.03 for both) than the time-matched controls, which remained significant after controlling for gestational age at delivery (adjusted odds ratio, 1.52; 95% confidence interval, 1.01-2.28; adjusted odds ratio, 2.12; 95% confidence interval, 1.16-3.88, respectively). Digital spatial profiling revealed that programmed death-ligand 1 was increased in villitis-positive regions of the SARS-CoV-2 (logFC, 0.47; adjusted P value =.002) and villitis of unknown etiology (logFC, 0.58; adjusted P value =.003) cases, but it was conversely decreased in villitis-positive regions of the infectious villitis group (log FC, -1.40; adjusted P value <.001).

CONCLUSION

Chronic villitis seems to be the most specific histopathologic finding associated with SARS-CoV-2 maternal infection. Chronic villitis involves damage to the vasculosyncytial membrane of the chorionic villi, which are involved in gas and nutrient exchange, suggesting potential mechanisms of placental (and perhaps neonatal) injury, even in the absence of vertical transmission. Surprisingly, changes in protein expression in SARS-CoV-2-associated villitis seem to be more similar to villitis of unknown etiology than to infectious villitis.

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.

Collateral Damage in the Placenta during Viral Infection in Pregnancy: A Possible Mechanism for Vertical Transmission and an Adverse Pregnancy Outcome

In mammals, the placenta is a connection between a mother and a new developing organism. This tissue has a protective function against some microorganisms, transports nutrients, and exchanges gases and excretory substances between the mother and the fetus. Placental tissue is mainly composed of chorionic villi functional units called trophoblasts (cytotrophoblasts, the syncytiotrophoblast, and extravillous trophoblasts). However, some viruses have developed mechanisms that help them invade the placenta, causing various conditions such as necrosis, poor perfusion, and membrane rupture which, in turn, can impact the development of the fetus and put the mother's health at risk. In this study, we collected the most relevant information about viral infection during pregnancy which can affect both the mother and the fetus, leading to an increase in the probability of vertical transmission. Knowing these mechanisms could be relevant for new research in the maternal-fetal context and may provide options for new therapeutic targets and biomarkers in fetal prognosis.

Neonatal arterial thrombosis: an arcane COVID sequelae

We describe a case of a term neonate with a swollen right arm and weakened pulses, diagnosed with arterial thromboembolism in the right axillary and brachial arteries. Treatment involved heparin, followed by enoxaparin, resulting in significant improvement. Maternal SARS-CoV-2 infection during pregnancy was considered as a potential factor, supported by the newborn's reactive COVID antibodies. The authors hypothesise a potential correlation between neonatal thrombosis and maternal SARS-CoV-2 infection during pregnancy. It is important to note that this association remains speculative and warrants further investigation for validation. The case underscores the importance of recognising and managing neonatal arterial thrombosis, especially in the context of maternal illness. We discuss the case in detail and review current knowledge on this condition.

SARS-CoV-2 in early pregnancy-does it affect the aneuploidy screening markers and cause pregnancy loss?

BACKGROUND

It is known that vertical transmission of various infections poses a potential risk to the fetus, especially in early pregnancy. Potential effects of SARS-CoV-2 infection on early pregnancy and placental formation and functions still remain unknown.

AIM

To determine the alterations of prenatal aneuploidy screening markers in a group of pregnant women who were SARS-CoV-2 positive during the first trimester. The secondary goal was to assess pregnancy loss rates.

METHOD

The study group consisted of pregnant women who were diagnosed with mild forms of SARS-CoV-2 infection before the screening test at any time in early pregnancy. The control group included pregnant women who were not diagnosed with SARS-CoV-2 infection during their pregnancy. SARS-CoV-2 infection was detected by RT-PCR in the nasopharyngeal swab samples. Multivariate linear regression analysis was performed due to evaluate effect of SARS-CoV-2 infection on NT and serum aneuploidy screening parameters taking maternal age and gestational age which the COVID-19 RT-PCR test result was positive into account.

RESULTS

We did not find any significant difference between the COVID-19-positive and COVID-negative groups in gestational age at screening, sonographic measurements of CRL, NT, and serum levels of PAPP-A, free hCG, and triple test serum markers even after accounting for maternal age and gestational age which the COVID-19 RT-PCR test result was positive. There was no statistically significant difference in pregnancy loss.

CONCLUSIONS

We did not find any evidence for unfavorable prenatal biochemical, ultrasound markers of fetal aneuploidy screening tests, and pregnancy loss rates in our study group.

An Update on COVID-19-Associated Placental Pathologies

COVID-19 pregnancies are associated with increased rates of premature delivery and stillbirths. It is still a matter of debate whether there is a COVID-19-associated pattern of placenta pathology. We updated our previously published results on a systematic literature review and meta-analysis of COVID-19 pregnancies. In total, 38 reports on 3677 placentas were evaluated regarding histopathological changes. Maternal vascular malperfusion (32%), fetal vascular malperfusion (19%), acute and chronic inflammation (20% and 22%) were frequent pathologies. In non-COVID-19 pregnancies, placentas show similar histologic patterns and mainly similar frequencies of manifestation. It has to be taken into account that there might be an observation bias, because some findings are diagnosed as a "pathology" that might have been classified as minor or unspecific findings in non-COVID-19 placentas. COVID-19 placentitis occurs in 1-2% of cases at the most. In conclusion, this updated meta-analysis indicates that COVID-19 infection during pregnancy does not result in an increased rate of a specific placenta pathology and COVID-19 placentitis is rare.

Evolution of Fetal Growth in Symptomatic Sars-Cov-2 Pregnancies

INTRODUCTION

SARS-CoV-2 is a viral disease with potentially devastating effects. Observational studies of pregnant women infected with SARS-CoV-2 report an increased risk for FGR. This study utilizes data from a prospective SARS-CoV-2 registry in pregnancy, investigating the progression of fetuses to fetal growth restriction (FGR) at birth following maternal SARS-CoV-2 and evaluating the hypothesis of whether the percentage of SGA at birth is increased after maternal SARS-CoV-2 taking into account the time interval between infection and birth.

MATERIALS & METHODS

CRONOS is a prospective German registry enrolling pregnant women with confirmed SARS-CoV-2 infection during their pregnancy. SARS-CoV-2 symptoms, pregnancy- and delivery-specific information were recorded. The data evaluated in this study range from March 2020 until August 2021. Women with SARS-CoV-2 were divided into three groups according to the time of infection/symptoms to delivery: Group I<2 weeks, Group II 2-4 weeks, and Group III>4 weeks. FGR was defined as estimated and/or birth weight<10% ile, appropriate for gestational age (AGA) was within 10 and 90%ile, and large for gestational age (LGA) was defined as fetal or neonatal weight>90%ile.

RESULTS

Data for a total of 2,650 SARS-CoV-2-positive pregnant women were available. The analysis was restricted to symptomatic cases that delivered after 24+0 weeks of gestation. Excluding those cases with missing values for estimated fetal weight at time of infection and/or birth weight centile, 900 datasets remained for analyses. Group I consisted of 551 women, Group II of 112 women, and Group III of 237 women. The percentage of changes from AGA to FGR did not differ between groups. However, there was a significantly higher rate of large for gestational age (LGA) newborns at the time of birth compared to the time of SARS-CoV-2 infection in Group III (p=0.0024), respectively.

CONCLUSION

FGR rates did not differ between symptomatic COVID infections occurring within 2 weeks and>4 weeks before birth. On the contrary, it presented a significant increase in LGA pregnancies in Group III. However, in this study population, an increase in the percentage of LGA may be attributed to pandemic measures and a reduction in daily activity.

Diffusion-sensitized magnetic resonance imaging highlights placental microstructural damage in patients with previous SARS-CoV-2 pregnancy infection

INTRODUCTION

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been a major global health problem since December 2019. This work aimed to investigate whether pregnant women's mild and moderate SARS-CoV-2 infection was associated with microstructural and vascular changes in the placenta observable in vivo by Intravoxel Incoherent Motion (IVIM) at different gestational ages (GA).

METHODS

This was a retrospective, nested case-control of pregnant women during the SARS-CoV-2 pandemic (COVID-19 group, n = 14) compared to pre-pandemic healthy controls (n = 19). MRI IVIM protocol at 1.5T was constituted of diffusion-weighted (DW) images with TR/TE = 3100/76 ms and 10 b-values (0,10,30,50,75,100,200,400,700,1000s/mm2). Differences between IVIM parameters D (diffusion), and f (fractional perfusion) quantified in the two groups were evaluated using the ANOVA test with Bonferroni correction and linear correlation between IVIM metrics and GA, COVID-19 duration, the delay time between a positive SARS-CoV-2 test and MRI examination (delay-time exam+) was studied by Pearson-test.

RESULTS

D was significantly higher in the COVID-19 placentas compared to that of the age-matched healthy group (p < 0.04 in fetal and p < 0.007 in maternal site). No significant difference between f values was found in the two groups suggesting no-specific microstructural damage with no perfusion alteration (potentially quantified by f) in mild/moderate SARS-Cov-2 placentas. A significant negative correlation was found between D and GA in the COVID-19 placentas whereas no significant correlation was found in the control placentas reflecting a possible accelerated senescence process due to COVID-19.

DISCUSSION

We report impaired microstructural placental development during pregnancy and the absence of perfusion-IVIM parameter changes that may indicate no perfusion changing through microvessels and microvilli in the placentas of pregnancies with mild/moderate SARS-Cov-2 after reaching negativity.

Clinical Features of SARS-CoV-2 Infection During Pregnancy and Associated Placental Pathologies

SUMMARY

We reviewed the clinicopathologic findings of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-exposed placentas at our institution. We identified patients diagnosed with SARS-CoV-2 during pregnancy (March-October 2020). Clinical data included gestational age at diagnosis and delivery and maternal symptoms. Hematoxylin and eosin slides were reviewed for maternal vascular malperfusion, fetal vascular malperfusion, chronic villitis, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Immunohistochemistry (IHC) for coronavirus spike protein and RNA in situ hybridization (ISH) for SARS-CoV-2 was performed on a subset of blocks. A review of placentas from age-matched patients received March-October 2019 was conducted as a comparison cohort. A total of 151 patients were identified. Placentas in the 2 groups were similar in weight for gestational age and had similar rates of maternal vascular malperfusion, fetal vascular malperfusion, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Chronic villitis was the only significantly different pathologic finding between cases and controls (29% of cases showed chronic villitis vs. 8% of controls, P <0.001). Overall, 146/151 (96.7%) cases were negative for IHC and 129/133 (97%) cases were negative for RNA ISH. There were 4 cases that stained positively for IHC/ISH, 2 of which showed massive perivillous fibrin deposition, inflammation, and decidual arteriopathy. Coronavirus disease 2019 (COVID-19)-positive patients were more likely to self-identify as Hispanic and more likely to have public health insurance. Our data suggests SARS-CoV-2 exposed placentas that stain positively for SARS-CoV-2 show abnormal fibrin deposition, inflammatory changes, and decidual arteriopathy. The group of patients with clinical COVID-19 are more likely to show chronic villitis. IHC and ISH evidence of viral infection is rare.

Study of placental histopathology in COVID-19 mothers at a dedicated COVID-19 hospital in India

Introduction

Maternal infections can affect the placenta, which acts as a fetomaternal barrier. This study aimed to determine the spectrum of morphologic alterations in the placentas of pregnancies complicated by SARS-CoV-2 infection and the impact on fetal or neonatal outcomes.

Materials and Methods

This is a prospective case-control study. One hundred SARS-CoV-2 positive pregnant women and an equal number of SARS CoV-2 negative pregnant women in their third trimester who delivered at our tertiary care center between December 2020 and November 2021 were enrolled in the study. This study was conducted at the end of the first wave and during the second COVID-19 wave. Histopathological examination of the placentas was done using Amsterdam consensus criteria. We observed for evidence of maternal vascular malperfusion [MVM], fetal vascular malperfusion, and inflammation in the placenta.

Results

The clinical findings were compared between the cases and controls. Evidence of MVM was seen in comparable numbers between the cases and controls, but as it involved less than 30% of the placental disc, it was considered an insignificant finding. Deciduitis was seen in equal proportions in both groups. The comparison between the asymptomatic and symptomatic groups failed to show any difference in placental pathology between both groups. There was no adverse fetal outcome seen in the pregnancies complicated by SARS-CoV-2 infection.

Conclusion

Placental injury at the microscopic level was observed but was neither significant nor specific to the SARS-CoV-2 infection. SARS CoV-2 infection did not influence the placental pathology. Also, no adverse neonatal outcomes were observed.

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.

The influence of SARS-CoV-2 on the immune system elements and on the placental structure. Clinical, histological and immunohistochemical study

BACKGROUND

The effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy remain relatively unknown.

AIM

We present this original paper where we analyzed 60 parturients, at term, 30 without associated infection (C-) and 30 with associated infection (C+), present at birth.

METHODS

We analyzed the blood count and placental microscopic structure through classical and immunohistochemical staining and observed the placental areas affected by the presence of SARS-CoV-2.

RESULTS

SARS-CoV-2 infection was accompanied by a decrease in the number of lymphocytes, the number of platelets and the presence of placental structural changes, identifying extensive areas of amyloid deposits, placental infarcts, vascular thrombosis, syncytial knots, with a decrease in placental vascular density and the presence of infection in the cells located at decidual level, at syncytiotrophoblast level and at the level of the cells of the chorionic plate, still without overcoming this barrier and without causing any fetal infection in the analyzed cases.

CONCLUSIONS

This study shows that the invasion of SARS-CoV-2 in the placenta can produce significant structural changes, with a decrease in placental vascular density that can have significant implications on proper fetal perfusion. Also, the presence of immunoreactivity at the level of decidua, the placental villi, as well as the chorionic plate proves that the virus can overcome the maternal-fetal barrier. However, in the analyzed cases there were no fetal infections at birth, which may show that local placental factors can be a protective filter for the fetus.

The Hemostatic System in Newborns and the Risk of Neonatal Thrombosis

Newborns are the most vulnerable patients for thrombosis development among all children, with critically ill and premature infants being in the highest risk group. The upward trend in the rate of neonatal thrombosis could be attributed to progress in the treatment of severe neonatal conditions and the increased survival in premature babies. There are physiological differences in the hemostatic system between neonates and adults. Neonates differ in concentrations and rate of synthesis of most coagulation factors, turnover rates, the ability to regulate thrombin and plasmin, and in greater variability compared to adults. Natural inhibitors of coagulation (protein C, protein S, antithrombin, heparin cofactor II) and vitamin K-dependent coagulation factors (factors II, VII, IX, X) are low, but factor VIII and von Willebrand factor are elevated. Newborns have decreased fibrinolytic activity. In the healthy neonate, the balance is maintained but appears more easily converted into thrombosis. Neonatal hemostasis has less buffer capacity, and almost 95% of thrombosis is provoked. Different triggering risk factors are responsible for thrombosis in neonates, but the most important risk factors for thrombosis are central catheters, fluid fluctuations, liver dysfunction, and septic and inflammatory conditions. Low-molecular-weight heparins are the agents of choice for anticoagulation.

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.

Pathological Examination of the Placenta in COVID-19-Positive Mothers: A Short Communication

Background & Objective

It was declared that COVID-19 might be more severe in symptomatic pregnant patients. This study was conducted to examine the pathological indices of the placenta in pregnant women who were diagnosed with COVID-19.

Methods

A total of 20 COVID-19-positive mothers were enrolled in this study. Detailed placental pathology findings were compared between subjects based on the history of abortion or occurrence of preterm delivery, hypertension, and diabetes.

Results and Conclusion

Intervillositis was the most frequent abnormality of the placenta. There was also a significant association between abortion history and maternal vascular malperfusion (MVM; P=0.02). The placental abnormalities were found to be increased in women with COVID-19, regardless of maternal comorbidities. Further studies are needed to compare the placental pathology between COVID-19-positive women and healthy women.

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.

Leveraging the placenta to advance neonatal care

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

Impact of COVID-19 during pregnancy on placental pathology, maternal and neonatal outcome - A cross-sectional study on anemic term pregnant women from a tertiary care hospital in southern India

Background

SARS-CoV-2 infection during pregnancy may cause adverse maternal, neonatal and placental outcomes. While tissue hypoxia is often reported in COVID-19 patients, pregnant women with anemia are suspected to be more prone to placental hypoxia-related injuries.

Methods

This hospital-based cross-sectional study was conducted between August-November 2021, during COVID-19 second wave in India. Term pregnant women (N=212) admitted to hospital for delivery were enrolled consecutively. Since hospital admission mandated negative RT-PCR test for SARS-CoV-2 virus, none had active infection. Data on socio-demography, COVID-19 history, maternal, obstetric, and neonatal outcomes were recorded. Pre-delivery maternal and post-delivery cord blood samples were tested for hematological parameters and SARS-CoV-2 IgG. Placentae were studied for histology.

Results

Of 212 women, 122 (58%) were seropositive for SARS-CoV-2 IgG, but none reported COVID-19 history; 134 (63.2%) were anemic. In seropositive women, hemoglobin (p=0.04), total WBC (p=0.009), lymphocytes (p=0.005) and neutrophils (p=0.02) were significantly higher, while ferritin was high, but not significant and neutrophils to lymphocytes (p=0.12) and platelets to lymphocytes ratios (p=0.03) were lower. Neonatal outcomes were similar. All RBC parameters and serum ferritin were significantly lower in anemic mothers but not in cord blood, except RDW that was significantly higher in both, maternal (p=0.007) and cord (p=0.008) blood from seropositive anemic group compared to other groups. Placental histology showed significant increase in villous hypervascularity (p=0.000), dilated villous capillaries (p=0.000), and syncytiotrophoblasts (p=0.02) in seropositive group, typically suggesting placental hypoxia. Maternal anemia was not associated with any histological parameters. Univariate and multivariate logistic regression analyses of placental histopathological adverse outcomes showed strong association with SARS-CoV-2 seropositivity but not with maternal anemia. When adjusted for several covariates, including anemia, SARS-CoV-2 seropositivity emerged as independent risk factor for severe chorangiosis (AOR 8.74, 95% CI 3.51-21.76, p<0.000), dilated blood vessels (AOR 12.74, 95% CI 5.46-29.75, p<0.000), syncytiotrophoblasts (AOR 2.86, 95% CI 1.36-5.99, p=0.005) and villus agglutination (AOR 9.27, 95% CI 3.68-23.32, p<0.000).

Conclusion

Asymptomatic COVID-19 during pregnancy seemed to be associated with various abnormal placental histopathologic changes related to placental hypoxia independent of maternal anemia status. Our data supports an independent role of SARS-CoV-2 in causing placental hypoxia in pregnant women.

Predictive factors for severe placental damage in pregnant women with SARS-CoV-2 infection

INTRODUCTION

SARS-Cov-2 infection during pregnancy can lead to severe placental lesions characterized by massive perivillous fibrin deposition, histiocytic intervillositis and trophoblast necrosis. Diffuse placental damage of this kind is rare, but can sometimes lead to obstetric complications, such as intrauterine fetal death (IUFD). The objectives of this study were to identify possible predictors of severe placental lesions.

METHODS

We retrospectively studied 96 placentas from SARS-Cov-2 positive pregnant women who gave birth between March 2020 and March 2022. Cases with and without severe placental lesions were compared in terms of clinical and laboratory findings.

RESULTS

Twelve of the 96 patients had severe placental lesions. There was no significant association with diabetes, obesity or severe clinical maternal disease. In contrast, presence of severe placental lesions was significantly associated with neonatal intensive care, cesarean section, prematurity, IUFD, intrauterine growth restriction (IUGR), gestational age, maternal hypofibrinogenemia and thrombocytopenia. No cases of severe placental lesions were observed in vaccinated patients or in those with the Omicron variant.

DISCUSSION

In these patients, severe placental lesions due to SARS-Cov-2 were significantly associated with the presence of coagulation abnormalities (hypofibrinogenemia and thrombocytopenia), IUGR and gestational age. These results support laboratory and ultrasound monitoring of these parameters in pregnant women with SARS-Cov-2 infection, especially during the second trimester, to predict potential negative fetal outcomes.

A neonatal case of cerebral venous sinus thrombosis with intrauterine onset after COVID-19 infection during pregnancy: Cause or coincidence?

Coronavirus 19 disease (COVID-19) is known to predispose patients to increased thrombotic events and the risk is higher in pregnancy which is already a hypercoagulable state. Vertical transmission of the disease during pregnancy was neglected according to data early in the pandemic, however, despite conflicting results from different studies, there is an increasing suspicion of vertical transmission with the rise of new fetal and neonatal cases and perinatal transmission can be higher than expected. An early term neonate, with the history of maternal COVID-19 infection in the start of third trimester, was diagnosed as cerebral venous sinus thrombosis and chronic hemorrhagic ischemia, with intrauterine onset.

Histopathological Changes in Placenta of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2) Infection and Maternal and Perinatal Outcome in COVID-19

Background

Whether vertical transmission or placental pathology occurs after maternal infection during pregnancy remains unknown. There is a clear need for studies on the impact of COVID-19 on pregnancy outcome. A systemic inflammatory or hypercoagulable state may be the contributing factor for placental pathology.

Methods

The pregnant women with COVID-19 who delivered between May 2020 and May 2021 were followed and data were collected about pregnancy course and placentas were examined for macro- and microscopical changes and were compared to controls with non-infected women.

Results

Placenta of COVID-19-infected females had increased prevalence of decidual arteriopathy and placental injury reflecting hypoxia and uteroplacental insufficiency within the intervillous space. Features of maternal vascular malperfusion such as increased syncytial knots were present in 100% cases. Fibrinoid necrosis was seen in 100% cases and increased focal perivillous fibrin depositions were presented in 37.7% cases. About one fourth infected placentas had evidence of villitis. Even after matching for comorbidities like preeclampsia, these changes were present.

Conclusion

The most common pathological findings of the placenta of COVID-19 infections are signs of maternal and fetal malperfusion. Future studies should target infections in different stage of gestation, including first and second trimesters.

A Review of Coronavirus Disease 2019 in Pregnancy

Pregnancy is an independent risk factor for morbidity and mortality in coronavirus disease 2019 (COVID-19) with increased rates of operative delivery, intensive care unit admission, and mechanical ventilation as well as a possible increased risk of death, independent of other risk factors, compared with nonpregnant women with COVID-19. Furthermore, pregnancy outcomes are worse in those with COVID-19 with increased risk for preeclampsia, venous thromboembolism, preterm birth, miscarriage, and stillbirth compared with pregnant women without COVID-19. Importantly, pregnant women of nonwhite ethnicity appear to be at greater risk of severe COVID-19, necessitating improved access to care and closer monitoring in these women. The management of COVID-19 in pregnancy is largely similar to that in nonpregnant people; however, there is an important emphasis on multidisciplinary team involvement to ensure favorable outcomes in both mother and baby. Similarly, vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is safe in pregnancy and improves maternal and neonatal outcomes.

SARS-CoV-2 Infection: A Clinical and Histopathological Study in Pregnancy

During pregnancy, SARS-CoV-2 infection is associated with several adverse outcomes, including an increased risk of pre-eclampsia, preterm delivery, hypertensive disorders, gestational diabetes, and fetal growth restriction related to the development of placenta vascular abnormalities. We analyzed human placenta from full-term, uncomplicated pregnancies with SARS-CoV-2 infection during the first, second, or third trimesters of gestation. We studied, by the immunohistochemistry technique, the expression of CD34 and podoplanin (PDPN) as markers of vasculogenesis to find any differences. As secondary outcomes, we correlated maternal symptoms with placental histological alterations, including fibrin deposits, lymphocyte infiltration in the villi, edema, and thrombi. Our results showed a PDPN expression around the villous stroma as a plexiform network around the villous nucleus of fetal vessels; significant down-regulation was observed in the villous stroma of women infected during the third trimester. CD34 showed no changes in expression levels. During SARS-CoV-2 infection, the most common maternal symptoms were fever, anosmia, ageusia and asthenia, and the majority were treated with paracetamol, corticosteroids and azithromycin. Patients that required multiple symptomatic treatments evidenced a large amount of fibrin deposition in the villi. Certainly, PDPN plays a key role in healthy placental vasculogenesis and thus in its proper physiology, and SARS-CoV-2 surely alters its normal expression. Further studies are necessary to understand what mechanisms are being altered to try to avoid possible complications for both the mother and fetus in terms of the contagions that will still occur.

Mechanical ventilation and death in pregnant patients admitted for COVID-19: a prognostic analysis from the Brazilian COVID-19 registry score

BACKGROUND

The assessment of clinical prognosis of pregnant COVID-19 patients at hospital presentation is challenging, due to physiological adaptations during pregnancy. Our aim was to assess the performance of the ABC2-SPH score to predict in-hospital mortality and mechanical ventilation support in pregnant patients with COVID-19, to assess the frequency of adverse pregnancy outcomes, and characteristics of pregnant women who died.

METHODS

This multicenter cohort included consecutive pregnant patients with COVID-19 admitted to the participating hospitals, from April/2020 to March/2022. Primary outcomes were in-hospital mortality and the composite outcome of mechanical ventilation support and in-hospital mortality. Secondary endpoints were pregnancy outcomes. The overall discrimination of the model was presented as the area under the receiver operating characteristic curve (AUROC). Overall performance was assessed using the Brier score.

RESULTS

From 350 pregnant patients (median age 30 [interquartile range (25.2, 35.0)] years-old]), 11.1% had hypertensive disorders, 19.7% required mechanical ventilation support and 6.0% died. The AUROC for in-hospital mortality and for the composite outcome were 0.809 (95% IC: 0.641-0.944) and 0.704 (95% IC: 0.617-0.792), respectively, with good overall performance (Brier = 0.0384 and 0.1610, respectively). Calibration was good for the prediction of in-hospital mortality, but poor for the composite outcome. Women who died had a median age 4 years-old higher, higher frequency of hypertensive disorders (38.1% vs. 9.4%, p < 0.001) and obesity (28.6% vs. 10.6%, p = 0.025) than those who were discharged alive, and their newborns had lower birth weight (2000 vs. 2813, p = 0.001) and five-minute Apgar score (3.0 vs. 8.0, p < 0.001).

CONCLUSIONS

The ABC2-SPH score had good overall performance for in-hospital mortality and the composite outcome mechanical ventilation and in-hospital mortality. Calibration was good for the prediction of in-hospital mortality, but it was poor for the composite outcome. Therefore, the score may be useful to predict in-hospital mortality in pregnant patients with COVID-19, in addition to clinical judgment. Newborns from women who died had lower birth weight and Apgar score than those who were discharged alive.

COVID-19 on Pregnancy Outcomes, Mental Health and Placenta: Focus in Latin America

The COVID-19 pandemic has impacted many aspects of health and society worldwide. One vulnerable group that faced SARS-CoV-2 infection is pregnant women, who were considered to have potentiated risk factors. In physiological pregnancy, maternal systems have several changes and adaptations to support fetal development. These changes involve regulations of cardiovascular, respiratory, and immunologic systems, among others, which SARS-CoV-2 could severely alter. Furthermore, the systemic effects of viral infection could be associated with placental dysfunction and adverse pregnancy outcomes, which have been studied from the start of the pandemic to date. Additionally, pregnancy is a condition of more significant mental health vulnerability, especially when faced with highly stressful situations. In this chapter, we have collected information on the effect of COVID-19 on maternal mortality, the SARS-CoV-2 infection rate in pregnancy, and the impact on pregnancy outcomes, maternal mental health, and placental function, with a particular focus on studies that consider the Latin American population.

COVID-19 and pregnancy: clinical outcomes; mechanisms, and vaccine efficacy

As the COVID-19 pandemic continues into its third year, emerging data indicates increased risks associated with SARS-CoV-2 infection during pregnancy, including pre-eclampsia, intrauterine growth restriction, preterm birth, stillbirth, and risk of developmental defects in neonates. Here, we review clinical reports to date that address different COVID-19 pregnancy complications. We also document placental pathologies induced by SARS-CoV-2 infection, entry mechanisms in placental cells, and immune responses at the maternal-fetal interface. Since new variants of SARS-CoV-2 are emerging with characteristics of higher transmissibility and more effective immune escape strategies, we also briefly highlight the genomic and proteomic features of SARS-CoV-2 investigated to date. Vector and mRNA-based COVID-19 vaccines continue to be rolled out globally. However, because pregnant individuals were not included in the vaccine clinical trials, some pregnant individuals have safety concerns and are hesitant to take these vaccines. We describe the recent studies that have addressed the effectiveness and safety of the current vaccines during pregnancy. This review also sheds light on important areas that need to be carefully or more fully considered with respect to understanding SARS-CoV-2 disease mechanisms of concern during pregnancy.

Functional consequences of SARS-CoV-2 infection in pregnant women, fetoplacental unit, and neonate

The SARS-CoV-2 infection causes COVID-19 disease, characterized by acute respiratory distress syndrome, bilateral pneumonia, and organ failure. The consequences of maternal SARS-CoV-2 infection for the pregnant woman, fetus, and neonate are controversial. Thus, it is required to determine whether there is viral and non-viral vertical transmission in COVID-19. The disease caused by SARS-CoV-2 leads to functional alterations in asymptomatic and symptomatic pregnant women, the fetoplacental unit and the neonate. Several diseases of pregnancy, including COVID-19, affect the fetoplacental function, which causes in utero programming for young and adult diseases. A generalized inflammatory state and a higher risk of infection are seen in pregnant women with COVID-19. Obesity, diabetes mellitus, and hypertension may increase the vulnerability of pregnant women to infection by SARS-CoV-2. Alpha, Delta, and Omicron variants of SARS-CoV-2 show specific mutations that seem to increase the capacity of the virus to infect the pregnant woman, likely due to increasing its interaction via the virus S protein and angiotensin-converting enzyme 2 receptors. This review shows the literature addressing to what extent COVID-19 in pregnancy affects the pregnant woman, fetoplacental unit, and neonate. Prospective studies that are key in managing SARS-CoV-2 infection in pregnancy are discussed.

Fetal demise and SARS-CoV-2 infection during pregnancy: Histopathological and immunohistochemical findings of three cases referred to the Colombian National Institute of Health

BACKGROUND

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection during pregnancy is related with adverse maternal, fetal, and neonatal outcomes. Placental SARS-CoV-2 involvement may include various degrees of inflammation and malperfusion leading to diverse pregnancy complications.

METHODS

Placental, fetal and umbilical cord samples of three fetal demise cases that occurred in the context of maternal SARS-CoV-2 infections were analyzed. Cases were notified to the Colombian SARS-CoV-2 National Surveillance System. RT-PCR and immunohistochemistry (IHC) analysis were employed to identify potential tissue viral involvement.

RESULTS

RT-PCR and IHC confirmed the presence of viral genomes and antigens in placental and umbilical cord tissues. Histopathological analysis revealed findings consistent with placental malperfusion and inflammation.

CONCLUSIONS

SARS-CoV-2 infection during pregnancy can lead to placental dysfunction and damage compromising fetal survival. Many questions regarding SARS-CoV-2 dynamics during pregnancy including placental physiopathology and in utero transmission are still pending definitive answers.

CORRELATION OF SARS-COV-2 EXPRESSION IN THE PLACENTA AND THE INCIDENCE OF PREECLAMPSIA

Background

The pandemic caused by SARS-CoV-2 also caused infection in some pregnant women. Some reports say this viral infection can show symptoms of preeclampsia.

Material and Methods

We analyzed 25 pregnant women with SARS-CoV-2 infection with 4 patients presenting with symptoms of preeclampsia. we performed routine blood analysis, renal function, liver function, and IHC examination to see the expression of viral proteins in the placenta.

Results

we obtained 4 patients with confirmed SARS-CoV-2 infection by RT-PCR. In these 4 cases, none of the cases showed expression of the SARS-CoV-2 viral protein in the placenta, and all 4 mothers were declared dead after treatment, and 2 babies delivered out of these 4 cases died. In one case we had fetal death in pregnancy while in one case prematurity. 2 babies born to mothers with SARS-CoV-2 infection with preeclampsia were born in good condition. There were no babies infected with SARS-CoV-2.

Conclusion

We conclude that SAR-CoV-2 infection in pregnant women with comorbidities can lead to a poor prognosis for both mother and baby. We cannot yet conclude whether SARS-CoV-2 infection can cause preeclampsia, but SARS-CoV-2 infection can exacerbate preeclampsia symptoms.

Mixed Intervillositis in SARS-CoV-2 Infection Associated with Fetal Death: A Case Report

Maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been shown in epidemiological studies to be associated with an increased risk of stillbirth. Several histopathologic features of placental SARS-CoV-2 infection have been proposed as potential causes of fetal death. We present a case of an otherwise healthy G3P1 women with mild symptoms of SARS-CoV-2 infection at 23 6/7 weeks of gestation. At 25 2/7 weeks, she presented with signs and symptoms of preterm labor and decreased fetal movements. Fetal death was diagnosed at admission. Placental pathology showed pronounced placental mixed intervillositis. Inflammatory infiltrate caused extreme narrowing of intervillous space leading to placental malfunction and fetal death. Placental tissue SARS-CoV-2 infection was confirmed by positive immunohistochemistry staining of syncytiotrophoblasts with spike protein antibody. The case presented suggests that SARS-CoV-2 associated inflammatory placental changes pose an elevated risk for the fetus.

SARS-CoV-2 vertical transmission in a twin-pregnant woman: a case report

SARS-CoV-2 has affected millions of people around the world in recent years. Among susceptible patients, pregnant women seem to be prone to serious complications. The possibility of SARS-CoV-2 vertical transmission represents one of the most debated topics in the literature, providing inconclusive results. We present a case of a confirmed vertical transmission in a monochorial diamniotic twin pregnancy complicated by a selective intrauterine growth restriction and gestational diabetes mellitus. The analysis of different biological specimens identifies the presence of the SARS-CoV-2 genome in the umbilical cord blood of both twins, and the placental histologic examination confirmed indirect signs of viral infection, supporting the hypothesis that a transplacental infection can occur. Despite the devastating impact that SARS-CoV-2 has worldwide, neonatal infections have been infrequently reported, but they can occur under certain biologic conditions. Deep knowledge of the biological mechanisms underlying the risk of SARS-CoV-2 vertical transmission might be useful to understand the pathophysiological bases and the possible long-term implication of a mother-to-child vertical transmission.

Human Maternal-Fetal Interface Cellular Models to Assess Antiviral Drug Toxicity during Pregnancy

Pregnancy is a period of elevated risk for viral disease severity, resulting in serious health consequences for both the mother and the fetus; yet antiviral drugs lack comprehensive safety and efficacy data for use among pregnant women. In fact, pregnant women are systematically excluded from therapeutic clinical trials to prevent potential fetal harm. Current FDA-recommended reproductive toxicity assessments are studied using small animals which often do not accurately predict the human toxicological profiles of drug candidates. Here, we review the potential of human maternal-fetal interface cellular models in reproductive toxicity assessment of antiviral drugs. We specifically focus on the 2- and 3-dimensional maternal placental models of different gestational stages and those of fetal embryogenesis and organ development. Screening of drug candidates in physiologically relevant human maternal-fetal cellular models will be beneficial to prioritize selection of safe antiviral therapeutics for clinical trials in pregnant women.

Evaluation of Safety Concerns for COVID-19 Immunization of Pregnant Women: a Systematic Review of Emerging Evidence

Objectives: There is an urgent need to review the status of COVID-19 vaccine immunization in pregnant women globally, so that adverse outcomes may be prevented. In this study, we performed a systematic review to evaluate the probable outcomes of COVID-19 vaccination in pregnant women. Materials and methods:An electronic search over three months (June 15-August 15, 2021) was conducted. Original studies evaluating safety concerns in pregnant women for COVID-19 vaccination were included. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 guidelines were used for data collection and reporting of findings. Results:COVID-19 vaccination in pregnant women was not associated with increased adverse effects or complications to the mother as well as the developing fetus or new-born compared to non-vaccinated pregnant women. Vaccinated pregnant women showed a robust immune response against COVID-19 infection. Conclusion:COVID-19 vaccination during pregnancy causes no significant health risks for the mother or the developing fetus or new-born.

Does COVID-19 infection acquired in different pregnancy trimester influence placental pathology?

OBJECTIVES

To determine the morphological characteristics of the placentas from COVID-19 positive mothers in regard to the trimester of COVID-19 infection onset and low weight molecular heparin (LMWH) treatment.

METHODS

Placentas were collected in the period April 1st till September 1st 2021 after delivery at Department of Obstetrics and Gynecology University Hospital Split, Croatia, and sent for pathological examination. Medical history and pathology reports were used to collect the data. Pregnant women were divided based on the onset of COVID-19 infection and stratified into low molecular weight heparin (LMWH)+ or LMWH-. Depending on the data distribution, the following test were used: chi-squared test. Student's t-test, Mann-Whitney U test, ANOVA and Kruskal-Wallis test.

RESULTS

In 38% of patients the onset of COVID-19 infection was the 1st trimester of pregnancy, in 27% in the 2nd and 35% of women were infected in the 3rd trimester The fetal vascular malperfusion (FVM) occurrence was statistically significantly higher in the LMWH- group and if the onset of infection was in the 2nd trimester, while the perivillous fibrin deposition was most likely to happen if the COVID-19 infection that occured in the 1st trimester of pregnancy.

CONCLUSIONS

The onset of COVID-19 infection has the influence on trophoblast damage and subsequent morphological appearance of the placenta. LMWH use in COVID positive pregnant women decreases the rate of the FVM in examined placentas.

Characteristics of Placental Histopathology in Women with Uncomplicated Pregnancies Affected by SARS-CoV-2 Infection at the Time of Delivery: A Single-Center Experience

The aim of this study was, firstly, to analyze the histopathological characteristics of placentas in women with uneventful pregnancies and affected by COVID-19 at the time of delivery; and secondly, to correlate histological findings to maternal and neonatal characteristics. In our single-center prospective observational study, 46 placentas from term uncomplicated singleton pregnancies of patients with a documented SARS-CoV-2 infection at the time of delivery underwent histological examination. Despite a normal feto-maternal outcome, most of the placentas (82.6%) presented signs of maternal vascular malperfusion, while features of fetal vascular malperfusion were found in 54% of cases. No correlation was detected between maternal and neonatal characteristics and the severity of blood circulation disease, and abnormal findings were also described in asymptomatic patients. Moreover, we did not find any maternal symptoms or clinical details allowing for the prediction of abnormal placental findings in pregnancy complicated by COVID-19 infection. Our results suggest that SARS-CoV-2 infection during pregnancy could lead to acute placental dysfunction.

The influence of COVID-19 pandemic on intrauterine fetal demise and possible vertical transmission of SARS-CoV-2

OBJECTIVE

The impact of COVID-19 on intrauterine fetal demise (IUFD) and vertical transmission of the SARS-CoV-2 from the mother to the fetus are crucial issues of the COVID-19 pandemic. In the current study, we aimed to detect the pandemic's influence on the IUFD and evaluate the vertical transmission of the SARS-CoV-2 through analysis of placental tissues collected from PCR positive women with IUFD above 20 weeks of gestation.

MATERIALS AND METHODS

The pregnant women above 20 weeks of gestation and had a fetus intrauterine demised during pandemic were included in the study. The pregnant women screened for COVID-19. Vertical transmission searched from placental tissues of COVID-19 positive women by RT-PCR tests for the presence of SARS-CoV-2 RNA. The number of IUFD before the pandemic and during the pandemic compared to assess the influence of the COVID-19 pandemic on the IUFD ratio.

RESULTS

Among 138 pregnant women with IUFD, 100 of them could screen for COVID-19 status. RT-PCR test results of 6 of the screened pregnant women were positive for SARS-CoV-2. Placental tissues of these six women were analyzed, and one test result was positive for SARS-CoV-2 RNA. The IUFD ratio was significantly increased during the pandemic.

CONCLUSION

It is clear that COVID-19 increases the IUFD ratio. Previous data for vertical transmission of SARS-CoV-2 during the second trimester is limited. We present the third case of literature that has positive placental results for SARS-CoV-2 RNA in the second trimester of pregnancy.

Placental pathology, neonatal birth weight, and Apgar score in acute and distant SARS-CoV-2 infection

BACKGROUND

Most research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy has been on acute infections with limited data on the effect of distant infection.

AIM

We examined placental pathology and neonatal outcomes in distant SARS-CoV-2 infection earlier in pregnancy compared to acute infections late in pregnancy/at birth and to non-SARS-CoV-2 infected patients with other placental pathologies/clinical presentations.

METHODS

Placentas birthed to unvaccinated patients with SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) testing and serology testing results from time of delivery were included in this study. A total of 514 singleton placentas between April 18, 2020, and July 26, 2021, were included: 77 acute SARS-CoV-2 infection (RT-PCR positive and serology negative); 222 distant SARS-CoV-2 infection (RT-PCR negative but serology IgG-positive); and 215 non-SARS-Cov-2 infected (RT-PCR negative, serology negative, and history negative) with other placental pathologies: preeclampsia/hypertension, intrauterine growth restriction (IUGR), diabetes, chorioamnionitis, and meconium. Placental pathology findings, Apgar scores, and neonatal birth weights were compared.

RESULTS

Placentas from the acute group had significantly more villous agglutination (10.4%, P = 0.015) and eosinophilic T-cell vasculitis (5.2%, P = 0.004) compared to placentas from the distant group (2.7% and 0%) and non-SARS-CoV-2 placentas (1.9% and 0.9%). One acute case showed SARS-CoV-2 placentitis and resulted in preterm delivery at 25 weeks. Both the preeclampsia/hypertension and the IUGR groups showed significantly more maternal vascular malperfusion findings compared to the acute (6.5%, 6.5% and 1.3%) and distant (7.7%, 7.7%, and 3.2%) groups. Fetal vascular malperfusion findings such as thrombosis of fetal vessels (17.4% P = 0.042) and intramural fibrin deposition (21.7% P = 0.026) were significantly higher in the IUGR group compared to acute (7.8%; 2.6%) and distant (3.6%; 8.1%) infection. Many neonates born to patients infected with SARS-CoV-2 had birth weights outside of 95% confidence range of observed birth weights. There was no association of Apgar scores with infection status or placental pathology.

CONCLUSION

Acute and distant SARS-CoV-2 infections present differing placental pathology.

RELEVANCE FOR PATIENTS

SARS-CoV-2 infection during pregnancy has demonstrable effects on the placenta with potential significant impacts for maternal and fetal health. Prevention of maternal SARS-CoV-2 infection, primarily through vaccination, remains the best mitigation strategy to prevent sequelae of maternal SARS-CoV-2 infection.

Doppler ultrasound findings in symptomatic pregnant women diagnosed with COVID-19

The primary aim of this study was to investigate the potential impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on maternal and foetal Doppler findings. Doppler ultrasound findings were compared in 40 pregnant women diagnosed with COVID-19 disease who required hospitalisation (group 1) and 30 healthy pregnant women (group 2). Maternal characteristics and birth histories were recorded. Body mass index, gestational week at birth, type of delivery, oligihydroamnios, pre-term birth (<37 weeks), low birth weight (<10 percentile), perinatal death and f1st and 5th minute Apgar scores were recorded. Birth weights and foetal biophysical profile (BPP) scores in group 1 were significantly lower than those in group 2. There was a statistically significant between-group difference in the umbilical artery pulsatility index (PI), umbilical artery resistive index (RI), middle cerebral artery (MCA) PI, MCA RI, mean uterine artery (UtA) PI, mean UtA RI and cerebroplacental ratio (CPR), the parameters used to evaluate foetal-maternal blood flow. In the pregnant group diagnosed with COVID-19 and hospitalised, all foetal-maternal Doppler indicators of foetal-maternal blood flow were impaired, and birth weights and BPP scores in these patients were statistically significantly lower than those in the healthy controls.Impact statementWhat is already known on this subject? Foetal and maternal vascular malperfusion characterised by decidual arteriopathy have been reported in pathologies of placentas from pregnant women with SARS-CoV-2 infection.What the results of this study add? It was determined that COVID-19 disrupted foetal and maternal blood flow.What the implications are of these findings for clinical practice and/or further research? Foetal biometric measurements and foetal Doppler may be useful in the follow-up of perinatal outcomes in pregnant women with COVID-19.

Limb ischaemia at birth in a new-born whose mother tested positive for COVID-19 one month before delivery

We report a case of right upper limb ischaemia diagnosed at birth in a neonate whose mother had presented with paucisymptomatic COVID-19 four weeks previously. Typical causes were investigated and excluded. Maternal morbidity and mortality resulting from COVID-19 during pregnancy is well recognised and documented, however, foetal and neonatal complications are increasingly being reported. Our case sheds further light on the diverse nature of such complications, and in particular this type of possible association related to their delayed onset.

SARS-CoV-2 Infection during Pregnancy and Histological Alterations in the Placenta

(1) Background: Despite the high number of cases of COVID-19 during pregnancy, SARS-CoV-2 congenital infection is rare. The role of the placenta as a barrier preventing the transmission of SARS-CoV-2 from the mother to the fetus is still being studied. This study aimed to evaluate the impact of SARS-CoV-2 infection on placental tissue. (2) Methods: This was a transversal monocentric observational study. In the study, we included pregnant women with COVID-19 who delivered at “Sfântul Pantelimon” Clinical Emergency Hospital between 1 April 2020 and 30 March 2022. Histological analyses, both macroscopic and microscopic, were performed for placentas that came from these cases. (3) Results: To date, a characteristic placental lesion has not been clearly demonstrated, but most findings include features of maternal and fetal vascular malperfusion, which probably reflect the reduction in placental blood flow due to low oxygen level from the hypoxic respiratory disease and underlying hypercoagulable state induced by the COVID-19 infection. (4) Conclusions: The histopathological aspects found in placentas that came from COVID-19-positive pregnant women are common for many other diseases, but when they are found together, they are highly suggestive for viral infectious involvement of the placenta.

SARS-CoV-2 Infection and Pregnancy: Maternal and Neonatal Outcomes and Placental Pathology Correlations

There is accumulating evidence on the perinatal aspects of COVID-19, but available data are still insufficient. The reports on perinatal aspects of COVID-19 have been published on a small group of patients. Vertical transmission has been noted. The SARS-CoV-2 genome can be detected in umbilical cord blood and at-term placenta, and the infants demonstrate elevated SARS-CoV-2-specific IgG and IgM antibody levels. In this work, the analysis of clinical characteristics of RT-PCR SARS-CoV-2-positive pregnant women and their infants, along with the placental pathology correlation results, including villous trophoblast immunoexpression status for SARS-CoV-2 antibody, is presented. RT-PCR SARS-CoV-2 amniotic fluid testing was performed. Neonatal surveillance of infection status comprised RT-PCR testing of a nasopharyngeal swab and the measuring of levels of anti-SARS-CoV-2 in blood serum. In the initial study group were 161 pregnant women with positive test results. From that group, women who delivered during the hospital stay were selected for further analysis. Clinical data, laboratory results, placental histomorphology results, and neonatal outcomes were compared in women with immunohistochemistry (IHC)-con SARS-CoV-2-positive and IHC SARS-CoV-2-negative placentas (26 cases). A positive placental immunoprofile was noted in 8% of cases (n = 2), whereas 92% of cases were negative (n = 24). Women with placental infection proven by IHC had significantly different pathological findings from those without. One infected neonate was noted (n = 1; 4%). Infection was confirmed in perinatal autopsy, as there was the intrauterine fetal demise. The potential course of the infection with the risk of vertical transmission and implications for fetal–neonatal condition is critical for proper clinical management, which will involve comprehensive, multidisciplinary perinatal care for SARS-CoV-2-positive patients.

Epidemiological and clinical characteristics of pregnant women and neonates with COVID-19 in Northwest Mexico

INTRODUCTION

The SARS-CoV-2 virus, which causes COVID-19, has spread quickly worldwide, causing millions of cases and thousands of deaths. Some risk factors in the general population are related to the development of severe COVID-19 or death, but in pregnant women and neonates, the information is limited.

OBJECTIVE

To determine the epidemiological and clinical characteristics of pregnant women and neonates diagnosed with COVID-19 by RT-PCR and serological tests, and analyze the relationship between the influenza vaccination and COVID-19 symptoms in infected pregnant women in Sinaloa state.

METHODS

We collected samples from 116 pregnant women and 84 neonates from the Women´s Hospital of Sinaloa. They were diagnosed with COVID-19 by RT-PCR and serological tests (IgG), and sociodemographic, clinical and laboratory parameters were recorded.

RESULTS

A total of 11.2% (13/116) of the pregnant women were RT-PCR+, 25% (29/116) were IgG+ and 4.3% (5/116) were positive for both tests. Symptoms such as rhinorrhea (P = .04), cough (P = .02) and polypnea (P = .04) in pregnant women were related to COVID-19, also leukocyte index was higher in pregnant women with COVID-19 (P = .03), but the associations were lost after the Bonferroni correction. No laboratory parameters or underlying diseases were associated with COVID-19, and most infected pregnant women had mild cases. We found an association between the influenza vaccine and less common COVID-19 symptoms in pregnant women who were infected (P = .01). A total of 7.2% (6/84) of neonates were RT-PCR+, 35.7% (30/84) were IgG+, and there were no symptoms or underlying diseases associated with neonates who were infected. In conclusion, this work demonstrated that some symptoms were related to COVID-19, most pregnant women and neonates had mild cases, and the influenza vaccine could decrease the severity of COVID-19 cases in pregnant women.

Review of Impact of COVID-19 on Maternal, Neonatal Outcomes, and Placental Changes

Coronavirus disease (COVID-19), caused by SARS-CoV-2, is a disease that has caused a global impact. COVID-19 is transmitted through airborne droplets, respiratory secretions, and direct contact. The pandemic has affected individuals of different ages, and studying the impact of COVID-19 on maternal and newborn outcomes is critical. In this review, we highlight the impact of COVID-19 infection in pregnancy and its repercussion in the maternal-fetal binomial. Physiological changes that occur during pregnancy have significant effects on the immune system, cardiopulmonary system, and coagulation, and these changes can result in an altered response to COVID-19 infection. The symptoms, risk factors, and maternal health consequences of COVID-19 were discussed. In addition, the impact of newborns born to mothers with COVID-19 was reviewed. Finally, placental changes and vertical transmission of COVID-19 during pregnancy were also discussed in this review.