Placental gross / microscopic abnormalities, nonneoplastic
Increased perivillous fibrin

Topic Completed: 1 October 2011

Minor changes: 18 February 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Increased perivillous fibrin

Mandolin S. Ziadie, M.D.
Page views in 2019: 2,418
Page views in 2020 to date: 1,115
Cite this page: Ziadie MS. Increased perivillous fibrin. website. Accessed June 4th, 2020.
Definition / general
  • Small amounts of fibrin are commonly scattered throughout the normal placenta
  • Diffusely increased amounts of perivillous fibrin involving stem and terminal villi and large enough to be grossly visible are a significant pathologic finding
  • Increased fibrin may impair gas exchange and lead to growth restriction, oligohydramnious, premature birth (Arch Pathol Lab Med 1994;118:698), neurologic impairment or fetal death
Gross description
  • Strands of pale, firm parenchyma
Microscopic (histologic) description
  • Abundant perivillous fibrin that obliterates the intervillous space with loss of the syncytiotrophoblast
  • Requires at least one area of full thickness involvement / entrapment of at least half of the villi on a single slide
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