Placental Immunity Against Viral Infections: Defensive Mechanisms and Impact on Preterm Birth

The placenta serves as a critical organ during pregnancy, not only facilitating nutrient and oxygen exchange between mother and fetus but also acting as an immunological barrier to protect the developing fetus from pathogens. This article explores the placenta's defensive mechanisms against viral infections, including cellular, molecular, and immunological strategies. It further examines how certain viruses, such as cytomegalovirus (CMV), Zika virus (ZIKV), and SARS-CoV-۲, can evade these defenses, leading to placental inflammation and complications like preterm birth. Recent studies highlight the importance of understanding these interactions to develop preventive strategies and improve pregnancy outcomes.