Inflammation at the Maternal–Fetal Interface: Mechanisms Linking Maternal–Fetal Immunity to Preeclampsia and Fetal Growth Restriction

Inflammation is a physiological and tightly regulated component of normal pregnancy, contributing to implantation, placental development, and the initiation of parturition. The placenta functions as an active immunological hub, coordinating innate and adaptive immune responses to maintain tolerance while protecting against infection. Preeclampsia and fetal growth restriction (FGR) are major causes of maternal and perinatal morbidity worldwide and represent central manifestations of placental disease. Increasing evidence indicates that these conditions share key pathophysiological mechanisms, including placental dysfunction and maladaptive maternal immune responses. When immune regulation at the maternal-fetal interface becomes disrupted, inflammatory pathways contribute to impaired placental development and vascular maladaptation. In this context, excessive immune activation-driven by inflammasome signaling, Th1/Th17 polarization, and altered natural killer and macrophage function-can compromise placental perfusion, promote antiangiogenic imbalance, and lead to systemic endothelial dysfunction. This review, therefore, focuses on how immune dysregulation contributes to placental dysfunction in preeclampsia and FGR, synthesizing current knowledge of the maternal-fetal immune interface and exploring therapeutic strategies that link pathogenic mechanisms to targeted interventions. A deeper understanding of placental immunology and inflammatory signaling is essential to develop precision therapies. Established therapies, including low-dose aspirin, low-molecular-weight heparin, and antenatal corticosteroids, aim to mitigate inflammation and optimize fetal outcomes, while adjunctive strategies target oxidative stress, nutritional deficits, and the maternal microbiome. Emerging approaches such as cytokine-targeted biologics, inflammasome inhibitors, and mesenchymal stem cell therapies show promise but require rigorous safety and efficacy evaluation. Future research should prioritize biomarker validation, pathway-specific interventions, and equitable implementation to reduce inflammation-driven pregnancy complications.