Nonneoplastic placental conditions and abnormalities
Placental findings in specific conditions
Toxemia of pregnancy (preeclampsia and eclampsia)

Topic Completed: 1 November 2011

Minor changes: 29 October 2020

Copyright: 2002-2020,, Inc.

PubMed Search: Toxemia of pregnancy preeclampsia eclampsia[title]

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Toxemia of pregnancy (preeclampsia and eclampsia). website. Accessed November 23rd, 2020.
Definition / general
  • Preeclampsia is a pregnancy specific hypertensive disorder diagnosed by the presence of three main signs: hypertension, proteinuria and edema diagnosed after 20 weeks gestational age (usually begins at 32 weeks but may present earlier in patients with preexisting kidney disease or hypertension or hydatidiform moles)
  • Diagnosed in 6% of pregnant women, usually primigravidas, in last trimester
  • Eclampsia is preeclampsia complicated by convulsions, disseminated intravascular coagulation (DIC) affecting liver, kidney, brain, heart and placenta due to thrombosis of arterioles and capillaries
  • Early onset disease is attributed to abnormal superficial implantation resulting in diminished blood supply to the placenta
  • Late onset disease is attributed to excessive or ischemic trophoblasts in maternal circulation
  • Maternal hypertension due to endothelial release of vasoactive substances that lead to endothelial damage
  • Deliver baby
Gross description
  • Most placentas are smaller than expected although a subset are larger than expected
  • Infarcts and retroplacental hematomas are more common
Microscopic (histologic) description
  • Placenta: villous ischemia (increased syncytial knots, thickening of trophoblastic basement membrane, villous hypovascularity, villous agglutination and infarction), fibrinoid necrosis of uterine vessels and acute atherosis; more tortuous or densely distributed spiral and basal arteries than normal (Hum Pathol 1997;28:353), inappropriate trophoblastic immaturity (Hum Pathol 1995;26:594)
  • Brain: gross or microscopic hemorrhage; small vessel thrombi
  • Kidneys: endothelial cell swelling, fibrinogen derived amorphous dense deposits on endothelial side of glomerular basement membrane; severe disease may cause bilateral renal cortical necrosis
  • Liver: hemorrhage, fibrin thrombi
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