Extracellular Vesicles in Pregnancy: From Maternal–Fetal Communication to Environmental Perturbation

Pregnancy is a uniquely sensitive moment during which environmental exposures may have profound and long-lasting consequences for maternal health, placental function, and fetal development. A successful pregnancy depends on continuous molecular communication among maternal, placental, and fetal compartments. The disruption of these processes by environmental stressors may increase the risk of pregnancy complications, impaired neurodevelopment, and susceptibility to non-communicable diseases later in life. Pregnant women are exposed to dynamic mixtures of chemical, physical, occupational, behavioral, and social stressors from the air, diet, drinking water, consumer products, and residential or workplace environments. The pregnancy exposome framework integrates these external exposures with internal biological responses, including oxidative stress, inflammation, metabolic dysregulation, epigenetic alterations, and changes in circulating biomolecules. However, the mechanisms through which exposure-related signals are transmitted across the maternal–placental–fetal unit remain incompletely understood. Extracellular vesicles may be a key component of this communication network as they transfer protected molecular cargoes, including proteins, lipids, metabolites, and regulatory nucleic acids. Understanding how environmental exposures modify extracellular vesicle biogenesis, composition, and function may reveal mechanisms linking the pregnancy exposome to placental dysfunction, adverse pregnancy outcomes, fetal programming, and early biomarkers of biological effects. This review examines the role of extracellular vesicles in physiological maternal–fetal communication and critically summarizes current human and experimental evidence on how environmental exposures may affect EV characteristics and function during pregnancy, with particular attention to their potential involvement in placental dysfunction and adverse pregnancy outcomes.