Umbilical Cord

Question 1

Most common abnormality of umbilical cord

Answer 1

Single umbilical artery (SUA) or two vessel cord

Question 2

What is considered a short cord?

Answer 2

Less than 35 cm

Question 3

What is the main cause of a short umbilical cord?

Answer 3

Failure of embryonic in-folding

Question 4

Lack of fetal movement may also cause short umbilical cords. What are some reasons there might be lack of fetal movement?

Answer 4

Central nervous or musculoskeletal abnormalities
Oligohydramnios
Multiple gestation

Question 5

What is considered a long umbilical cord?

Answer 5

Greater than 80 cm

Question 6

What are some complications associated with long umbilical cords?

Answer 6

Polydramnios
Cord knot
Nuchal cord
Vasa previa

Question 7

Cord knots occur when:

Answer 7

Fetus moves through a loop of cord creating a knot

Seen with monoamniotic multiple gestations

Question 8

How often are cord knots diagnosed prenatally?

Answer 8

Rarely

Question 9

What is a nuchal cord?

Answer 9

Entanglement of the umbilical cord around the fetal neck

Question 10

How often are nuchal cords found?

Answer 10

In 25% of pregnancies

Question 11

When is a nuchal cord worrisome?

Answer 11

If two or more tight loops around the neck

Question 12

How can nuchal cords be diagnosed?

Answer 12

Use color Doppler to differentiate between nuchal cord and nuchal translucency
Look for evidence of neck indention or cord flattening

Question 13

What is vasa previa?

Answer 13

Fetal blood vessels presenting at internal os first

Question 14

Why is vasa previa significant?

Answer 14

Rupture of blood vessels during labor can be fatal

Question 15

Risk factors for vasa previa:

Answer 15

Velamentous cord insertion
Succenturiate lobe
Low lying placenta
Long cord
Polyhydramnios
Abnormal fetal position

Question 16

What are the types of cord masses and where do they originate?

Answer 16

Omphalomesenteric and allantoic cysts: remnant of either duct, near fetal end of cord
Pseudocysts: anywhere along the cord
Hemangioma: near placental cord insertion site
Hematoma: near placental cord insertion site (wherever cordocentesis occurred)
Herniation: at fetal insertion site

Question 17

What can be associated with omphalomesenteric or allantoic cysts?

Answer 17

Abdominal wall defects and genitourinary abnormalities

Question 18

What are pseudocysts of the umbilical cord caused by?

Answer 18

Focal degeneration of Wharton jelly

Question 19

What is the most common tumor of the umbilical cord?

Answer 19

Hemangioma

Question 20

Hematomas in an umbilical cord are usually the result of:

Answer 20

An invasive procedure (cordocentesis)

Question 21

Hematomas are associated with ________ loss rate.

Answer 21

50%

Question 22

What are the indications to perform an umbilical artery Doppler?

Answer 22

IUGR
abnormal biophysical profile
Abnormal AFI
Multiple gestations

Question 23

Where will the umbilical artery demonstrate a higher resistance?

Answer 23

At fetal cord insertion site especially when fetus is breathing

Question 24

What is the resistive index?

Answer 24

(S-D)/S

Systole minus diastole divided by systole

Question 25

What is the pulsatility index?

Answer 25

(S-D)/mean

Systole minus diastole divided by the mean of those two

Question 26

As pregnancy progresses, it is normal to demonstrate a _______________________ pattern.

Answer 26

Lower resistance

Question 27

After 18-20 weeks what is abnormal flow?

Answer 27

Absent diastolic flow

Question 28

Reversed end diastolic flow can be normal.

T/F

Answer 28

False, it’s NEVER normal

Question 29

Abnormally high resistance in the umbilical artery suggests:

Answer 29

Fetal compromise.

Question 30

Where do the chorionic villi of the placenta receive nutrients from the blood?

Answer 30

In the intervillous spaces

Question 31

Sonographic exam of placenta reveals 7 cm well circumscribed, hypoechoic mass. The Sonographer should evaluate the fetus for evidence of:

Answer 31

Hydrops
Fetal cardiomegaly
IUGR
Polyhydramnios