Pre-eclampsia toxemia (PET) is a multisystem disease characterized by impaired organ perfusion resulting from vasospasm and activation of the coagulation system. PET is defi ned as hypertension and proteinuria appearing after the 20th week of gestation and resolving within 6 to 12 weeks of delivery. It occurs in 2% to 3% of all pregnancies and is more common in primigravida or the fi rst pregnancy with a particular partner. Other risk factors include a positive family history, pre-existing hyper tension, diabetes mellitus, multiple pregnancy, increasing maternal age, and obesity. Th e pathogenesis of PET appears to result from abnormal placenta formation (termed 'placentation'). Failure of the second phase of trophoblast invasion results in the lack of destruction of the muscularis layer of the spiral arterioles, impairing vasodilation in response to increases in blood fl ow, resulting in placental ischemia. Th e ischemic placenta releases vasoactive substances, leading to systemic endothelial injury and systemic organ dysfunction. As pregnancy progresses, placenta ischemia worsens, and the mother becomes hypovolemic and hypertensive and may develop renal dysfunction. Th ere is disordered prostaglandin metabolism, with an imbalance between vasoconstrictive thromboxane and vasodilatory prostacyclin, resulting in platelet dysfunction, endothelial damage, and further vasoconstriction.