Placenta‐derived extracellular vesicles: Signal messengers shuttling across the maternal‐fetal barrier

Abstract Intercellular communication across the maternal‐fetal barrier is essential for maintaining physiological balance during pregnancy. As the structural foundation of the maternal‐fetal barrier, the placenta is the core site for material exchange and signaling between the mother and the fetus. Placenta‐derived extracellular vesicles (PEVs), owing to their nanoscale size and lipid bilayer membrane structure, can pass through the maternal‐fetal barrier via mechanisms such as endocytosis and transcytosis across the syncytiotrophoblast. Enriched in proteins, miRNAs, and lipids, PEVs contribute to immune homeostasis at the maternal‐fetal interface and support fetal growth and development. They are increasingly recognized as key mediators of information exchange between the mother and the fetus. Numerous studies have indicated that in significant pregnancy complications like preeclampsia, both the concentration and cargo of PEVs undergo remarkable changes, which are closely associated with the pathological processes of pregnancy. This suggests the potential utility of PEVs as biomarkers and therapeutic targets for pregnancy‐related disorders. Based on the latest research advancements, this review systematically collates the biological properties of PEVs as signal messengers and analyzes their physiological and pathological functions during pregnancy, aiming to provide new insights for research and clinical management.