Anatomy and Pathology of the Placenta 3 Flashcards

Describe abnormalities of uteroplacental and fetoplacental vasculature and their complications: preeclampsia, abruption, fetal thrombotic vasculopathy.

1
Q

What are some common abnromalities of implantation?

A
  • Placenta previa
    • placenta implants very low in uterus
    • covers internal os
    • cervical dilation at the time of labor can cause severe bleeding and potentially fetal and/or maternal death
  • Ectopic pregnancy
    • implantation outside of the uterus
    • most common location is the fallopian tube
  • Placenta accreta
    • placenta grows into myometrial smooth msucle
    • due to defective endometrium
      • previous C-section or prior endometrial curettage increases risk
    • key feature is perivillous fibrinoid, which is implantation directly upon myometrium without intervening decidua
  • Placenta increta
    • invasion deeper into the myometrium
  • Placenta percreta
    • full-thickness invasion into the myometrium
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2
Q

List the abnormalities of the uteroplacental vasculature that can occur.

A
  • Placental abruption
  • Preeclampsia
  • Acute atherosis
  • Maternal vascular underperfusion
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3
Q

List the vascular abnormalities of the fetoplacental vasculature that can occur.

A
  • Thrombosis
  • Significant obstruction in larger vessels
  • Fetal thrombotic vasculopathy (FTV)
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4
Q

What is placental abruption?

A
  • Rupture of a retroplacental (decidual) blood vessel
    • often related to maternal hypertension
  • Abruption occurs when a large hematoma occurs
    • causes separation of the placental from blood supply
    • fetal death is the consequence
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5
Q

What is pre-eclampsia? What is the clinical presentation? What is the pathology?

A
  • Narrowing or thrombosis of retroplacental (decidual) blood vessels is commonly seen
    • causes ischemia and often placental infarts
  • Numerous placental infarcts will compromise the delivery of oxygena nd nutrients to the fetus
    • results in fetal growth restriction or fetal death
  • Classic vascular lesion is acute atherosis
  • Overall pathologic changes referred to as maternal vascular underperfusion
  • Clinical peresentation
    • hypertension
    • edema
    • proteinuria
    • symptoms cease after delivery
  • Pathology
    • decidual vasculopathy - abnormal decidual vessels
      • fibrinoid necrosis of vessel walls
      • atherosis/mural foam cells
    • multiple infarcts
    • abruption
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6
Q

What is fetal thrombotic vasculopathy (FTV)? What are some common causes?

A
  • Term used to describe lesions of the fetoplacental vasculature
    • Clinical associations
      • preeclampsia
      • intrauterine growth restriction
      • intrauterine fetal demise
      • neonatal seizures
      • amputation necrosis
  • Common causes:
    • Stasis
      • cord compression - hypercoiling, velamentous umbilical cord insersion, true knot, cord entanglement
      • right heart failure
      • polycythemia
    • Hypercoagulability
      • thrombophilic disorders, acquired or genetic
    • Vascular damage
      • infection
      • meconium
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7
Q

What are some “downstream” effects of significant obstruction of larger fetal vessels?

A
  • Chorionic villous vasculature is lost
    • villi known as avascular villi
    • considered evidence of upstream fetal vascular thrombosis
  • Maternal supply is maintained and trophoblastic layers persist
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8
Q

What are some common umbilical cord pathologies?

A
  • Length < 35 cm is short and > 70 cm is long
  • Coiling/strictures
    • normal coiling is 1-3 coils/10cm
  • Knots
  • Velamentous insertion
  • Single umbilical artery
  • Meconium-associated myonecrosis
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9
Q

What are the fetal outcomes associated with placental pathology?

A
  • Normal
  • Preterm delivery
  • Fetal growth restriction
  • Neurological injury
  • Infection
  • Death/stillbirth
  • Others
    • syndromes
    • tumors
    • gestational trophoblastic disease
    • hydrops
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