Maternal-Fetal Impact of Respiratory Viral Infections: Immune Mechanisms and Clinical Outcomes.

Pregnancy is a unique immunological state characterized by physiological adaptations that support fetal growth and development. These immune changes, however, can leave pregnant women more vulnerable to severe outcomes from infections, including those caused by respiratory viruses. Respiratory viral infection during pregnancy can increase maternal morbidity and the likelihood of developing long-lasting neurodevelopmental consequences in the offspring, including autism spectrum disorder, schizophrenia, and other behavioral conditions, particularly in male offspring. Some respiratory viruses can infect reproductive tissues, placenta, and fetuses to cause detrimental pregnancy outcomes. Other respiratory viruses do not leave the respiratory tract but cause systemic maternal immune activation (MIA) that can also be detrimental to pregnancy and fetal outcomes. While antivirals may limit severe disease, they are not always effective at limiting MIA and adverse pregnancy outcomes, highlighting the need for a deeper understanding of the mechanisms that mediate these outcomes. Maternal vaccination offers protection against viral diseases for both mother and young. The effectiveness of these interventions is often limited by barriers such as concerns about vaccine and drug safety and restricted access to care and information. Addressing these challenges and advancing mechanistic understanding are essential for improving maternal and fetal outcomes in the face of respiratory viral infections.