Viral Infections During Pregnancy: The Big Challenge Threatening Maternal and Fetal Health

Abstract

Viral infections during pregnancy are associated with adverse pregnancy outcomes, including maternal and fetal mortality, pregnancy loss, premature labor, and congenital anomalies. Mammalian gestation encounters an immunological paradox wherein the placenta balances the tolerance of an allogeneic fetus with protection against pathogens. Viruses cannot easily transmit from mother to fetus due to physical and immunological barriers at the maternal-fetal interface posing a restricted threat to the fetus and newborns. Despite this, the unknown strategies utilized by certain viruses could weaken the placental barrier to trigger severe maternal and fetal health issues especially through vertical transmission, which was not fully understood until now. In this review, we summarize diverse aspects of the major viral infections relevant to pregnancy, including the characteristics of pathogenesis, related maternal-fetal complications, and the underlying molecular and cellular mechanisms of vertical transmission. We highlight the fundamental signatures of complex placental defense mechanisms, which will prepare us to fight the next emerging and re-emerging infectious disease in the pregnancy population.

The plasma virome in longitudinal samples from pregnant patients

“…These findings raise important questions regarding exposures and experiences of populations to be explored in future studies. Finally, we employed a much broader analysis of the plasma virome during pregnancy, using the ViroCap enrichment method to improve virus detection with sequencing, than prior studies of viral infections which either studied only the classic and some emerging viruses ( Chudnovets et al., 2020 ; Sloan et al., 2022 ; Yu et al., 2022 ) or used metagenomic sequencing of a small number of samples ( Shah et al., 2020 ). A weakness of our study is the relatively small number of PTB patients.…”

“…Many viruses in the blood have unclear pathogenicity, although some evidence of their association with clinical conditions has been recently reported ( Kaczorowska and van der Hoek, 2020 ; Cebria-Mendoza et al., 2021a ; Stapleton et al., 2011 ; Fama et al., 2020 ; Kyathanahalli et al., 2021 ). This evidence raises the possibility of vertical transmission of the highly prevalent blood viruses to the fetus during pregnancy ( Racicot and Mor, 2017 ; Yu et al., 2022 ). In particular, the anelloviruses are one of the most abundant and diverse groups of viruses in healthy human blood ( Cebria-Mendoza et al., 2021b ), with some studies reporting >90% prevalence ( Spandole et al., 2015 ).…”

“…This is an important question to investigate, as many human viruses are present (often asymptomatically) in and on generally healthy, reproductive aged adults ( Wylie et al., 2014 ), and therefore there is potential for subsequent effects on reproductive outcomes. Maternal viral infections can result in adverse events during pregnancy and poor fetal outcomes ( Chudnovets et al., 2020 ; Yu et al., 2022 ). Pregnant patients are more susceptible to severe disease from some viral infections such as influenza, varicella, and COVID-19 when compared to the general population ( Siston et al., 2010 , Meijer et al., 2015 , Silasi et al., 2015 ; Adhikari et al., 2022 ).…”

Perspectives on the Technological Aspects and Biomedical Applications of Virus‐Like Particles/Nanoparticles in Reproductive Biology: Insights on the Medicinal and Toxicological Outlook

“…A detailed review on the transmission of several classic and upcoming viruses resulting in severe maternal–fetal outcomes has been provided recently. [ 10 ] Unfortunately, the exact mechanisms of viruses for immune invasion and transport across the placenta have not been identified. This has been attributed to the practical challenges in studying the placenta using conventional techniques.…”

Case Series of Successful Intravenous Immunoglobulin (IVIG) Treatment in 4 Pregnant Patients with Severe COVID-19-Induced Hypoxia

“…While there is no way of knowing whether the outcomes of the patients would have been different if compared with a placebo, IVIG may be a safe treatment consideration in pregnant women with severe COVID-19. We hope that this case series will inspire large controlled trials to be conducted with pregnant patients, not just with COVID-19, but with other viral mediated acute respiratory distress syndromes which this patient population historically has been more vulnerable to, including influenza [ 30 ].…”