SARS-CoV-2 Infection in Pregnancy: Clinical Signs, Placental Pathology, and Neonatal Outcome-Implications for Clinical Care

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.

Placental pathology in SARS-CoV-2 infected pregnancies: A single-institution retrospective cohort analysis

BACKGROUND

Our objectives were to determine 1) the prevalence and description of placental pathologic lesions in pregnancies complicated by SARS-CoV-2 infection compared to healthy controls and 2) whether the prevalence and/ or pattern of placental pathologic lesions differed in the few neonates who tested positive for SARS-CoV-2 in the first 48 hours of life at a busy urban county hospital.

METHODS

This study included all pregnant mothers who tested positive for SARS-CoV-2 and delivered at our institution from March 2020 to June 2021, while control placentas were collected from term pregnancies without complications.

RESULTS

Approximately 90% (n = 380/425) of placentas from pregnancies complicated by SARS-CoV-2 infections had placental pathologic lesions, compared to 32% (n = 16/50) of controls. The predominant lesions were acute histologic chorioamnionitis with or without fetal response (n = 209/380, 55%), maternal vascular malperfusion (n = 180/380, 47%), and other inflammatory lesions (n = 148/380, 39%). Only 14 (2.5%) infants tested positive for SARS-CoV-2 within the first 48 hours of life. There were no significant differences in placental histopathology between infants who tested positive vs. those that were negative for SARS-CoV-2. Placental lesions in mothers who tested positive for SARS-CoV-2 during the first vs. second vs. third pregnancy trimesters, were significantly different in the incidence of inflammatory placental pathologic lesions (n = 9/19, 53% vs. n = 37/98, 49% vs. n = 102/439, 31%, respectively; p < 0.01).

CONCLUSION

A significant proportion of women with SARS-CoV-2 infection during pregnancy at a single county hospital have inflammatory and vascular placental lesions at birth, raising questions regarding their downstream effects and clinical consequences.

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

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

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.

Placental Pathology After SARS-CoV-2 Infection in the Pre-Variant of Concern, Alpha / Gamma, Delta, or Omicron Eras

Objectives.The goal of this study is to describe placental pathology after infection with SARS-CoV-2 before the predominance of variants of concern (pre-VOC) and during eras of predominant transmission of the Alpha & Gamma (co-circulating), Delta, and Omicron variants. Methods. We used county-level variant data to establish population-level variant proportions, SARS-CoV-2 PCR to identify cases, and IgG serology to exclude latent infections from controls and histopathologic examination to identify placental pathology. Results. We report findings in 870 placentas from pregnancies complicated by SARS-CoV-2 including 90 with infection in the Alpha/Gamma era, 60 from the Delta era and 56 from the Omicron era. Features of maternal vascular malperfusion (MVM), including decidual arteriopathy, were significantly more frequent after SARS-CoV-2 infection. The risk of these findings varied over time, with the highest rates in the Delta era. Increased COVID-19 severity and the presence of comorbidities strengthened these associations. Conclusion. MVM is a feature of SARS-CoV-2 infection in pregnancy. Lesion frequency changed with the predominant circulating virus and should be considered with new variants.