Mediators of inflammation at the maternal-fetal interface are altered by SARS-CoV-2 infection and pandemic stress

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.

Pregnant individuals with uncomplicated pregnancies display pro-inflammatory immune changes when exposed to the COVID-19 pandemic

PROBLEM

The COVID-19 pandemic has been shown to have a detrimental impact on the mental health of pregnant individuals, and chronic stress can alter the immune profile. However, the effects of the COVID-19 pandemic on the immune system in pregnancy are still poorly understood. We aimed to evaluate the impact of pandemic exposure on the maternal immune profile in uncomplicated pregnancies.

METHOD OF STUDY

We collected blood and placenta samples from pregnant individuals exposed and unexposed to the pandemic to compare their immune and inflammatory profiles. We performed co-culture with circulating maternal immune cells and endothelial cells to assess endothelial activation. Statistical analysis was performed using unpaired t-test, Mann-Whitney, or Fisher's exact test as appropriate.

RESULTS

In exposed individuals, we observed a decreased proportion of Th2 cells (p < .0001) and Treg/Th17 ratio (p < .05), as well as an increased Th1/Th2 ratio (p < .0001). Levels of IL-1β (p < .01) and IL-18 (p < .01) were increased in the circulation of exposed participants, whilst other mediators were significantly decreased (IFNγ, IL-8, MCP-1, amongst others). Furthermore, we observed increased production of ICAM, hallmark of endothelial activation, when we co-cultured endothelial cells with immune cells from exposed individuals. Vaccination status impacted the cellular profile with increased proportions of Th1 and B cells in vaccinated participants.

CONCLUSION

Overall, we observed a pro-inflammatory bias in the circulation of pregnant individuals exposed to the COVID-19 pandemic, with otherwise uncomplicated pregnancies. Our work also supports an association between the increased risk of endothelial activation/hypertension and SARS-CoV2 infection, which might be driven in part by exposure to the pandemic and associated stressors.

Comparison of Maternal and Neonatal Outcomes between SARS-CoV-2 Variants: A Retrospective, Monocentric Study

The impact of SARS-CoV-2 variants on maternal and neonatal outcomes during pregnancy is still poorly understood, and the emergence of different variants has further complicated our understanding of the virus's effects. This retrospective, monocentric study aimed to fill this knowledge gap by analyzing the outcomes of pregnant women with acute SARS-CoV-2 infection caused by the Alpha, Delta, and Omicron variants. The study, conducted between December 2020 and March 2022 at San Marco Hospital, included 313 pregnant women with confirmed SARS-CoV-2 infection. The results showed that the Delta variant was associated with a significantly higher incidence of adverse outcomes, such as premature births, maternal intensive care unit admission, intrauterine growth restriction, and small for gestational age infants. Additionally, the Delta variant was linked to lower Apgar scores, higher maternal and fetal mortality rates, and increased levels of various biomarkers indicating more severe illness. Finally, the Delta variant also presented a greater possibility of vertical transmission. These findings underscore the complexity of understanding the impact of SARS-CoV-2 on pregnancy outcomes, especially considering the distinctive characteristics of different variants. By better understanding the specific impacts of each variant, appropriate preventive measures and management strategies can be implemented to optimize maternal and neonatal outcomes.