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
2
Q
List the abnormalities of the uteroplacental vasculature that can occur.
A
- Placental abruption
- Preeclampsia
- Acute atherosis
- Maternal vascular underperfusion
3
Q
List the vascular abnormalities of the fetoplacental vasculature that can occur.
A
- Thrombosis
- Significant obstruction in larger vessels
- Fetal thrombotic vasculopathy (FTV)
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
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
- decidual vasculopathy - abnormal decidual vessels
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
-
Clinical associations
-
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
-
Stasis
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
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
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