Placenta

Question 1

What is it called when the placenta completely or partially covers the internal os?

Answer 1

Placenta previa

Question 2

Classifications of Previa

Answer 2

Complete
Partial
Marginal

Question 3

What is considered a low lying placenta?

Answer 3

Less than 2 cm from internal os after 32 weeks

Question 4

Risk factors for previa

Answer 4

Multigravida/multiparous 
Prior c-section
Hx of therapeutic abortion
Advanced maternal age
Closely spaced pregnancies
Abnormal fetal position 
Maternal anemia
Hx of uterine leiomyomatas or infections

Question 5

Which approach is most accurate for diagnosing placenta previa?

Answer 5

Endovaginal

Question 6

How would you measure to check for previa or low lying placenta?

Answer 6

From lowest edge of placenta to center of internal cervical os

Question 7

What do you call an abnormal placental attachment to the myometrium that doesn’t separate after delivery?

Answer 7

Placenta accreta

Question 8

Classifications of placental attachment

Answer 8

Accreta
Increta
Percreta

Question 9

Which is the least invasive form of placental attachment?

Answer 9

Accreta

Question 10

When the villa penetrate the ___________ but not the myometrium it is considered accreta.

Answer 10

Decidua

Question 11

Increta is:

Answer 11

When the villi penetrate/invade myometrium but not serosa

Question 12

What is percreta?

Answer 12

Villi penetrate through myometrium and serosa and may attach to adjacent organs

Question 13

Risk factors for placenta accreta

Answer 13

Previa
Prior c section
Prior uterine surgery
Advanced maternal age.

Question 14

When the placenta does not separate from the uterus during delivery it results in:

Answer 14

Massive hemorrhage

Question 15

Undiagnosed increta and percreta are associated with:

Answer 15

High maternal mortality.

Question 16

Sonographic evaluation of placenta accreta

Answer 16

Absent, thin, or irregular myometrial interface.

Question 17

What may Color Doppler demonstrate with placenta accreta?

Answer 17

Increased periplacental vascularity

Question 18

What is a succenturiate placenta?

Answer 18

Accessory lobe(s) connected to main placenta by blood vessels

Question 19

Succenturiate placenta can cause a higher incidence of:

Answer 19

Eccentric cord insertion, which increases risk of vasa previa
And of placental infarction

Question 20

Sonographic findings of succenturiate placenta

Answer 20

Two separate areas of placental tissue without obvious connection

Question 21

What use does color Doppler have when assessing a succenturiate placenta?

Answer 21

Helps identify connecting vessels between lobes

Can identify vasa previa in LUS and cervical os

Question 22

What is a circumvallate placenta?

Answer 22

Has a raised or rolled edge that may involve all or part of placental circumference
An abnormal attachment of placental membranes to fetal placental surface

Question 23

What is a circummarginate placenta?

Answer 23

Abnormal attachment of placental membranes into fetal placental surface with a flat or smooth membrane transition

Question 24

What occurs with circumvallate/circummarginate placentas?

Answer 24

Basal plate area is larger than fetal surface

Question 25

What risks are there with complete circumvallation?

Answer 25

``` Bleeding Low birth weight/IUGR Premature rupture of membranes Premature labor Placental abruption Fetal anomalies ```

Question 26

What will you see Sonographically with a circumvallate placenta?

Answer 26

An elevated and thickened placental edge

Question 27

Types of abnormal cord insertions

Answer 27

Battledore | Velamentous

Question 28

What else is a battledore placenta called?

Answer 28

Marginal cord

Question 29

What is a battledore placenta?

Answer 29

Eccentric cord attachment at placental margin Gives placenta a paddle appearance Associated with IUGR

Question 30

What is a velamentous cord insertion?

Answer 30

Cord not inserted into placental disk, inserted into free membranes Cord not protected by Wharton’s jelly and is easily damaged

Question 31

What risks are associated with velamentous cord insertion?

Answer 31

``` Vasa previa IUGR Prematurity Fetal anomalies Retained placenta Fetal bleeding ```

Question 32

What is a chorioangioma?

Answer 32

The most common benign tumor of placenta that arises from chorionic tissue

Question 33

Most chorioangiomas are small and don’t cause problems. When they get larger than ________ they can cause fetal and maternal complications

Answer 33

5 cm

Question 34

What complications are associated with large chorioangiomas?

Answer 34

``` Polyhydramnios Hydrops Fetal cardiomegaly IUGR Preterm labor Preeclampsia Elevated maternal serum alpha-fetoprotein ```

Question 35

Describe a chorioangioma sonographically.

Answer 35

``` Well circumscribed Round Hypoechoic-mixed echogenic Solid Usually near cord insertion site Just below chorionic plate Moderate vascularity ```

Question 36

What are some cystic lesions seen with placentas?

Answer 36

Placental lakes Perivillous fibrin deposits Hemangioma Teratoma

Question 37

What is an intervillous thrombus?

Answer 37

Coagulated blood in intervillous space

Question 38

When would an intervillous thrombus be significant?

Answer 38

If found in first trimester If large If numerous

Question 39

What is a perivillous fibrin deposit?

Answer 39

Triangular or rectangular hypoechoic areas under fetal surface of placenta. No clinical significance

Question 40

What is placental abruption?

Answer 40

Premature separation of placenta from endometrial surface | Disrupts placental and maternal circulation

Question 41

Placental abruption is one of the leading causes of :

Answer 41

Perinatal mortality

Question 42

Types of abruption

Answer 42

Retroplacental and marginal

Question 43

What occurs with retroplacental abruption?

Answer 43

Spiral arteries rupture and cause retroplacental hemorrhage

Question 44

Is retroplacental abruption a high pressure or low pressure bleed?

Answer 44

High pressure

Question 45

What is the most risky form of abruption?

Answer 45

Retroplacental

Question 46

Sonographic sensitivity for retroplacental abruption?

Answer 46

50%

Question 47

Marginal abruption is the:

Answer 47

Most common form of abruption

Question 48

What occurs with marginal abruption?

Answer 48

Edge of placenta separates from the uterus

Question 49

Is marginal abruption a high pressure bleed or a low pressure bleed?

Answer 49

Low pressure from rupture/tear of marginal veins

Question 50

What is marginal abruption AKA?

Answer 50

Subchorionic hematoma