Placental abruption

Placental abruption is premature separation of the placenta from the uterus.

General

Classic clinical manifestations:

• Vaginal bleeding (~70%).
• Abdominal pain (~50%).
• Fetal heart rate abnormalities (~70%).

Sign-out:

• Pathologists should sign-out this as "focal adherent retroplacental hematoma".
  • The pathologic findings may be due to abruption or manual removal of the placenta.

Gross

Features:

• Large adherent blood clot.
• Disc depression on maternal side.

Notes:

• Loosely attached clot less convincing.
• Central haemorrhage is the most worrisome.

Microscopic

Features:

1. Decidual hemorrhage.
   • Blood in the decidua.
2. Intravillous hemorrhage, AKA villous stromal hemorrhage.
   • "Bags of blood" - blood outside of vessels in the villi.
     • Should not be confused with congested villi.

Notes:

• There are no definitive microscopic findings for placental abruption.
• Intravillous hemorrhage is non-specific - may arise in the following: early placental infarct, cord compression, abdominal trauma.

Sign out

Usual nonspecific findings

PLACENTA, UMBILICAL CORD AND FETAL MEMBRANES, BIRTH:
- THREE VESSEL UMBILICAL CORD WITHIN NORMAL LIMITS.
- FETAL MEMBRANES WITHIN NORMAL LIMITS.
- PLACENTAL DISC WITH THIRD TRIMESTER VILLI, TWO SMALL PLACENTAL INFARCTS
  (0.8 CM AND 0.5 CM IN MAXIMAL DIMENSION) AND FOCAL PROMINENCE OF SYNCYTIAL KNOTS.

COMMENT:
There is no decidual hemorrhage or intravillous hemorrhage. The prominent syncytial knots
are a nonspecific finding suggestive of (focal) ischemia.

Note:

• The above is not diagnostic nor does it exclude the diagnosis of abruption.

See also

• Placenta.