Review of Viral Infections in Pregnancy Placental Immunity Vertical Transmission and Adverse Outcomes

Abstract

This review will focus on the effects of viral infections in pregnancy. Throughout gestation, viral infections are known to lead to adverse events including mortality of the fetus and mother, premature birth, miscarriage and congenital anomalies. The intricate immunological environment of pregnancy requires a fine balance in which the placenta must accept exposure to some allogeneic fetus while protecting against pathogens. Even though natural defense in the maternal-fetal interface prevents viral transmission, some viruses hijack poorly understood mechanisms that disrupt the integrity of the placenta, leading to vertical transmission and this can have severe consequences on fetal health. This review highlights the intricate relation of main viruses with pregnancy, including mechanisms in pathogenesis as well as maternal-fetal complications, and the cell and molecular substrate for trans placental infection. Key features of placental immune protection are trophoblast cells, innate immune populations, cytokine control, pathogen recognition and antimicrobial products, all being essential in preparing for new emerging challenges to the pregnant population.