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640 SectioN iii RepRoductive ` REPRODUCTIVE—PATHOlOgy RepRoductive ` REPRODUCTIVE—PATHOlOgy
Pregnancy complications
Abruptio placentae Premature separation (partial or complete) of
placenta from uterine wall before delivery
of infant. Risk factors: trauma (eg, motor
vehicle accident), smoking, hypertension,
preeclampsia, cocaine abuse.
Presentation: abrupt, painful bleeding
(concealed or apparent) in third trimester;
possible DIC (mediated by tissue factor
activation), maternal shock, fetal distress. May
be life threatening for mother and fetus.
Complete abruption with Partial abruption (blue arrow)
concealed hemorrhage with apparent hemorrhage (red
arrow)
Morbidly adherent Defective decidual layer abnormal attachment
placenta and separation after delivery. Risk factors:
prior C-section or uterine surgery involving
myometrium, inflammation, placenta previa, Normal Placenta
accreta
advanced maternal age, multiparity. Three types placenta Placenta
distinguishable by the depth of penetration: Stratum increta
basalis
Placenta accreta—placenta attaches to
myometrium without penetrating it; most Placenta
common type. percreta
Placenta increta—placenta penetrates into
myometrium.
Placenta percreta—placenta penetrates
(“perforates”) through myometrium and into
uterine serosa (invades entire uterine wall);
can result in placental attachment to rectum
or bladder (can result in hematuria).
Presentation: often detected on ultrasound prior
to delivery. No separation of placenta after
delivery postpartum bleeding (can cause
Sheehan syndrome).
Placenta previa Attachment of placenta over internal cervical
os. Risk factors: multiparity, prior C-section.
Associated with painless third-trimester
bleeding. A “preview” of the placenta is visible
through cervix.
Low-lying placenta (< 2 cm from internal
cervical os, but not over it) is managed
differently from placenta previa.
Partial placenta Complete placenta
previa previa
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