Placental gross / microscopic abnormalities, nonneoplastic
Placental site subinvolution

Topic Completed: 1 November 2011

Minor changes: 18 February 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Placental site subinvolution

Mandolin S. Ziadie, M.D.
Page views in 2019: 1,401
Page views in 2020 to date: 516
Cite this page: Ziadie MS. Placental site subinvolution. website. Accessed May 30th, 2020.
Definition / general
  • Delayed / incomplete sloughing of the modified spiral arteries in the superficial myometrium beneath the placental attachment site
  • Important cause of late postpartum bleeding
  • May be due to deficiency in immunologic factors necessary for normal involution of uteroplacental arteries
Microscopic (histologic) description
  • Curettings show large, dilated vessels that lack a medial coat and are partially / completely thrombosed
  • Trophoblasts may be present
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