Module 16: Placental Pathology Flashcards Preview

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Flashcards in Module 16: Placental Pathology Deck (48)
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1
Q

Define a grade 0 placenta:

A

Homogenous, chorionic plate is straight

2
Q

Define a grade 1 placenta:

A

Scattered echogenic areas, subtle undulations

3
Q

Define a grade 2 placenta:

A

Indentations, linear echogenic areas:

4
Q

Define a grade 3 placenta:

A

Indentations to basal layer, cystic areas, shadowing calcifications (after 36 weeks)

5
Q

What would constitute placentomegaly?

A

≥4 cm thick

6
Q

What would constitute as a thin placenta?

A

<1.5 cm

7
Q

Thickness of the placenta depends on what?

A

Gestational age

8
Q

What is the etiology of a thin placenta? (2)

A
  • Vascular deficienciency/infarct

- Pre-eclampsia

9
Q

What is a maternal lake?

A

Subchorionic fibrin deposition

10
Q

What is a placental lake?

A

Perivillus fibrin deposition

11
Q

What are placental infarcts?

A

Microscopic triangular shaped lesions on maternal side of placenta due to obstruction of maternal blood flow

12
Q

What can make a placenta look low?

A

Distended bladders

13
Q

A cervical length is usually what?

A

3-4 cm

14
Q

What is placental previa?

A

Low lying placenta

15
Q

Describe placenta previa with increasing severity:

A
  1. Low lying
  2. Marginal/Partial
  3. Complete (as uterus moves up, placenta is tearing - very serious)
16
Q

What is the clinical history for placenta previa?

A

Painless vaginal bleeding

17
Q

What may painful vaginal bleeding indicate?

A

Abruption

18
Q

What is the gold standard for investigating a low lying placenta?

A

EV

19
Q

What constitutes a low lying placenta?

A

When placenta is <2 cm from the internal os but not overlying it

20
Q

Describe partial vs complete placental previa:

A

Partial: placenta touches the internal os

Complete: Placenta completely covers the internal os

21
Q

If the placenta is <2 cm from the internal os after a post void bladder assessment at the 18 week scan, when is the patient to return?

A

24-28 weeks

And then every two weeks until placenta is seen migrating

22
Q

Why is color Doppler performed with EV at the cervix during the 24-28 week visit?

A

To see if there are vessels crossing the exit of the cervix

23
Q

Describe the variations in shape of a placenta: (3)

A
  1. Succenturiate
  2. Extrachorial
  3. Membranacea
24
Q

What are the two branches of extrachorial placenta?

A

Cicummarginate and circumvallate

25
Q

What is a succenturiate?

A

Accessory lobe of the placenta that is connected via vessels within the membrane

26
Q

What is seen with an extrachorial placenta?

A

Chorionic plate does not extend to edge of placenta and membrane extends over placenta

27
Q

What is seen with a circummarginate extrachorial placenta?

A

Flat ring at attachment to chorionic plate

28
Q

What is seen with a circumvallate extrachorial placenta?

A

Fold in the membrane at site of attachment

29
Q

What may an extrachorial placenta cause at delivery?

A

Antepartum hemorrhage

30
Q

What do you want to ensure with a synechiae (uterine scar)?

A

That the fetus is not attached to it, otherwise this would indicate amniotic band syndrome

31
Q

What is placenta membranacea?

A

Entire uterine surface is covered with placenta

32
Q

What is a battledore cord insertion?

A

Marginal cord insertion <3 cm from placental edge

33
Q

What is a velamentous cord insertion?

A

Cord inserting into the chorionic membranes and then vessels track to placenta

34
Q

What is vasa previa?

A

Fetal vessels across internal os

35
Q

What is placental abruption?

A

When placenta tears from uterine wall

36
Q

Where may placental hemorrhage occur?

A

Marginal, retroplacental

37
Q

What are the 3 different formations of placental abruption? (3)

A
  1. External bleeding, no hematoma
  2. Retroplacental hematoma without external bleeding
  3. Subchorionic hematoma with or without bleeding
38
Q

What are symptoms of placental abruptions? (4)

A
  • Preterm labor contractions
  • Bleeding
  • Pain
  • Fetal distress
39
Q

What is a teratoma?

A

Rare germ cell tumor of the placenta

40
Q

What is a chorioangioma of a placenta?

A

Vascular tumor that is a well defined complex mass that may cause hydrops heart failure.

41
Q

Define placenta accreta:

A

When the placenta attaches to the myometrium instead of the basalis

42
Q

Define placenta increta:

A

The placenta invades INTO myometrium

43
Q

Define placenta percreta:

A

Placenta invades through to perimetrium and even beyond

44
Q

What are the most common risks that occur with placenta accreta (In or Per)?

A
  • Post-partum bleeding due to difficult removal
  • Hysterectomy post delivery
  • DIC (disseminated intravascular coagulation - clotting throughout body)
45
Q

What conditions cause placentomegaly? (7)

A
  • Maternal diabetes
  • Maternal Anemia
  • Hydrops
  • Placental hemorrhage
  • Intrauterine infection
  • Partial mole
  • Chromosomal abnormalities
46
Q

What is vasoprevia?

A

Vessels connecting placenta with succenturiate lobe travelling across cervix

47
Q

What is accreta associated with? (9)

A
  • Placenta previa *
  • Only anterior placentas *
  • C-section *
  • Maternal age
  • Uterine abnormalities
  • Smoking
  • Myomectomy
  • Prev. Uterine surgery
  • Previous D&C
48
Q

What vessels does the umbilical cord normally have?

A

2 umb arteries and 1 vein