SARS-CoV-2 infection during pregnancy and preterm birth in Massachusetts from March 2020 through March 2021

Postpartum hemorrhage emerges as a key outcome of maternal SARS-CoV-2 omicron variant infection surge across pregnancy trimesters

BACKGROUND

Despite evidence showing changes in disease severity with the virus's evolution and vaccination efforts, the link between maternal, perinatal, and neonatal outcomes and SARS-CoV-2 infections during different pregnancy trimesters remains unclear, especially with the BA.5 and BF.7 Omicron subvariant surge in China in December 2022. This study investigates the correlation between maternal, perinatal, and neonatal outcomes and SARS-CoV-2 infection across various pregnancy trimesters.

METHODS

This prospective cohort study was conducted at two hospitals in southwest China, examining the clinical records and infection status of 2158 pregnant women registered between January 1, 2022, and September 30, 2023. Initially shielded from COVID-19, the population later experienced a significant infection surge. A comparative analysis evaluated maternal, perinatal, and neonatal outcomes between infected and uninfected subjects. Primary outcomes included pregnancy complications and premature births, while secondary outcomes encompassed cesarean sections, delivery complications, and neonatal outcomes.

RESULTS

Pregnant women infected with SARS-CoV-2 had higher incidence of placenta increta/percreta and postpartum hemorrhage compared to uninfected women. First trimester infections were associated with a lower incidence of intrahepatic cholestasis of pregnancy [aOR = 0.29, 95 % CI 0.13-0.63] but a higher incidence of preterm birth [aOR = 2.16, 95 % CI 1.25-3.71]. Third trimester infections increased the risk of postpartum hemorrhage [aOR = 2.74, 95 % CI 1.21-6.18].

CONCLUSION

SARS-CoV-2 infection during pregnancy is linked to increased incidence of placenta increta/percreta and postpartum hemorrhage. First trimester infections are associated with higher incidence of premature birth and lower incidence of intrahepatic cholestasis of pregnancy, while third trimester infections are linked to higher incidence of postpartum hemorrhage.

Preterm Birth and SARS-CoV-2: Does a Correlation Exist?

Introduction: The emergence of the SARS-CoV-2 virus and its subsequent global pandemic have raised significant concerns regarding its impact on pregnancy outcomes. This review aims to summarize the emerging data on the risk of preterm delivery in pregnant women infected with SARS-CoV-2. Materials and Methods: A systematic search was conducted from March 2020 to December 2023 using PubMed and Web of Science, following PRISMA guidelines. Studies correlating maternal COVID-19 infection with preterm birth were included. Results: Thirteen studies were analyzed, indicating a higher incidence of preterm birth in SARS-CoV-2-positive pregnant women compared to controls. The average incidence rate of preterm birth in infected patients was 18.5%, with a median of 12.75%, while non-infected women showed an average incidence of preterm birth of 10%, with a median of 8.2%. Discussion: Studies suggest an association between SARS-CoV-2 infection during pregnancy and increased risk of preterm birth and cesarean section. The severity of symptoms and underlying comorbidities further elevate this risk. Notably, infections during the third trimester pose the highest risk of preterm birth. Conclusion: Preventing SARS-CoV-2 infection during pregnancy is crucial to mitigate adverse obstetric outcomes. Close monitoring and tailored interventions for infected pregnant women, particularly those in later trimesters and with comorbidities, are imperative to reduce the risk of preterm birth and improve maternal-fetal outcomes.

Transplacental Transmission of SARS-CoV-2: A Narrative Review

Background and Objectives: The study aims to explore the potential for transplacental transmission of SARS-CoV-2, focusing on its pathophysiology, placental defense mechanisms, and the clinical implications for maternal and neonatal health. Materials and Methods: A comprehensive review of the current literature was conducted, analyzing studies on SARS-CoV-2 infection in pregnancy, the expression of key viral receptors (ACE2 and TMPRSS2) in placental cells, and the immune responses involved in placental defense. The review also examined the clinical outcomes related to maternal and neonatal health, including adverse pregnancy outcomes and neonatal infection. Results: The expression of ACE2 and TMPRSS2 in the placenta supports the biological plausibility of SARS-CoV-2 transplacental transmission. Histopathological findings from the infected placentas reveal inflammation, vascular changes, and the evidence of viral particles in placental tissues. Clinical reports indicate an increased risk of preterm birth, intrauterine growth restriction, and neonatal infection in pregnancies affected by COVID-19. However, the frequency and mechanisms of vertical transmission remain variable across studies, highlighting the need for standardized research protocols. Conclusions: SARS-CoV-2 can potentially infect placental cells, leading to adverse pregnancy outcomes and neonatal infection. While evidence of transplacental transmission has been documented, the risk and mechanisms are not fully understood. Ongoing research is essential to clarify these aspects and inform obstetric care practices to improve maternal and neonatal outcomes during the COVID-19 pandemic.

SARS-CoV-2 infection, inflammation and birth outcomes in a prospective NYC pregnancy cohort

Associations between antenatal SARS-CoV-2 infection and pregnancy outcomes have been conflicting and the role of the immune system is currently unclear. This prospective cohort study investigated the interaction of antenatal SARS-CoV-2 infection, changes in cytokine and HS-CRP levels, birthweight and gestational age at birth. 2352 pregnant participants from New York City (2020-2022) were included. Plasma levels of interleukin (IL)-1β, IL-6, IL-17A and high-sensitivity C-reactive protein (HS-CRP) were quantified in blood specimens obtained across pregnancy. Quantile and linear regression models were conducted to 1) assess the impact of antenatal SARS-CoV-2 infection, overall and by timing of detection of SARS-CoV-2 positivity (< 20 weeks versus ≥ 20 weeks), on birthweight and gestational age at delivery; 2) examine the relationship between SARS-CoV-2 infection and maternal immune changes during pregnancy. All models were adjusted for maternal demographic and obstetric factors and pandemic timing. Birthweight models were additionally adjusted for gestational age at delivery and fetal sex. Immune marker models were also adjusted for gestational age at specimen collection and multiplex assay batch. 371 (15.8%) participants were infected with SARS-CoV-2 during pregnancy, of which 98 (26.4%) were infected at < 20 weeks gestation. Neither SARS-CoV-2 infection in general nor in early or late pregnancy was associated with lower birthweight nor earlier gestational age at delivery. Further, we did not observe cytokine or HS-CRP changes in response to SARS-CoV-2 infection and thus found no evidence to support a potential association between immune dysregulation and the diversity in pregnancy outcomes following infection.