Placental gross / microscopic abnormalities, nonneoplastic
Placenta accreta, increta and percreta

Topic Completed: 1 October 2011

Minor changes: 18 February 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Placenta[title] accreta increta percreta

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Placenta accreta, increta and percreta. website. Accessed July 5th, 2020.
Definition / general
  • Abnormal implantation of the placenta
  • Villi are directly implanted into the myometrium without an intervening layer of deciduas, resulting in adherence of the placenta to the uterus, leading to a risk of postpartum bleeding, fever and uterine rupture
  • May require hysterectomy specimen for diagnosis
  • Accreta: partial or complete absence of decidua with adherence of placenta directly to the superficial myometrium
  • Increta: villi invade into but not through the myometrium
  • Percreta: villi invade through the full thickness of myometrium to the serosa; may cause uterine rupture
  • Associated with previous abortion, D&C or cesarean section; advanced maternal age; or uterine structural defects, which may lead to areas of abnormal / absent decidualized endometrium
  • 60% are associated with placenta previa (placenta implants in lower uterine segment or cervix, often with serious antepartum bleeding and premature labor)
Diagrams / tables

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Case reports
Gross description
  • Ragged tissue or incomplete cotyledons on maternal floor
  • Superficial acute hemorrhage near insertion of cord (due to excessive traction on cord during labor)
Gross images

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Figure 1

Placenta increta

Microscopic (histologic) description
  • Chorionic villi in direct contact with myometrial smooth muscle fibers
  • Absent / reduced decidua basalis layer with thick layer of fibrin, hemosiderin laden macrophages
Microscopic (histologic) images

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Placenta accreta

Figure 2 (H&E), figure 3 (actin)

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