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Placental gross/microscopic abnormalities, non-neoplastic

Placenta accreta, increta and percreta

Reviewers: Mandolin Ziadie, M.D. (see Reviewers page)
Revised: 15 November 2011, last major update October 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.


● 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)

Case reports

Arch Pathol Lab Med 2002;126:1557

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

Various images

Placenta increta

Micro description

● Chorionic villi in direct contact with myometrial smooth muscle fibers
● Absent / reduced decidua basalis layer with thick layer of fibrin, hemosiderin laden macrophages

Micro images

Placenta accreta

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



End of Placenta > Placental gross/microscopic abnormalities, non-neoplastic > Placenta accreta, increta and percreta

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