A nutrient overload hypothesis for the pathogenesis of preeclampsia: impaired placentation as a site-specific manifestation of chronic metabolic substrate excess

Preeclampsia is a major cause of maternal and fetal morbidity and mortality worldwide. Current models identify abnormal placentation, placental hypoperfusion, oxidative stress, endothelial dysfunction, angiogenic imbalance, immune dysregulation, and maternal vascular injury as central features of the disorder. While these mechanisms explain many downstream manifestations of disease, they do not fully explain why placental adaptation fails in some pregnancies but not others. This paper proposes a unifying hypothesis in which chronic metabolic substrate overload progressively creates a metabolically compromised uterine vascular environment before conception, reducing the capacity of maternal vessels to undergo the extensive physiological remodeling required for normal placentation. Repeated exposure to excess nutrient substrate may promote advanced glycation end-product formation, endothelial dysfunction, oxidative stress, vascular remodeling, and reduced vascular adaptability. Within this compromised environment, trophoblast invasion and spiral artery remodeling may occur less effectively, leading to placental hypoperfusion and subsequent manifestations of preeclampsia. Once placental dysfunction is established, sFlt-1-mediated renal injury may impair glomerular function, contributing to sodium and fluid retention and worsening hypertension and thereby creating a potential feedback loop that amplifies the maternal manifestations of preeclampsia. Established clinical risk factors may therefore converge, in some women, through impaired metabolic and vascular homeostasis rather than representing a single common pathophysiology. The hypothesis generates falsifiable predictions involving metabolic biomarkers, vascular function, placental biomarkers, and preconception interventions. If validated, it would identify maternal metabolic health before conception as a potentially important determinant of placental adaptation and preeclampsia risk.