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OB Pathology > The Umbilical Cord > Flashcards

The Umbilical Cord Flashcards

1
Q

What is the essential link for oxygen and important nutrients between the fetus the mother?

A

The umbilical cord

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2
Q

The _________ covers the cord and blends with the fetal skin at the umbilicus

A

amnion

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3
Q

The vascular connections within the cord serve a _____ function in the fetus

A

reverse

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4
Q

The umbilical vein carries ______ blood to the fetus.

A

oxygenated

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5
Q

The umbilical arteries bring ____ blood back to the ____.

A

used or deoxygenated blood,

placenta

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6
Q

When does the umbilical cord form?

A

First 5 weeks of gestation

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7
Q

The umbilical cord is made from the fusion of :

A

the omphalomesenteric (or yolk stalk) and allantoic ducts

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8
Q

Omphalomesenteric AKA

A

yolk stalk

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9
Q

An out-pouching from the urinary bladder forms the

A

urachus, which projects into the connecting stalk to form the allantois

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10
Q

The allantoic vessels become the _____ ______ ______.

A

definitive umbilical vessels

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11
Q

The umbilical cord is covered by the _______.

A

amniotic membrane.

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12
Q

The cord includes ___ arteries and ___ vein.

A

2, 1

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13
Q

What surrounds the vasculature in the umbilical cord?

A

Wharton’s Jelly

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14
Q

Diameter of umbilical cord:

A

1-2cm

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15
Q

Length of the umbilical cord:

A

40-60cm long

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16
Q

Describe the pathway of the umbilical arteries

A

arise from the fetal internal iliac arteries, course alongside the fetal bladder, and exit the umbilicus to form part of the umbilical cord

The paired umbilical arteries course along the entire length of the cord in a helicoidal fashion surrounding the umbilical vein

They then branch along the chorionic plate of the placenta

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17
Q

The umbilical vein enters the umbilicus and joins the

A

left portal vein

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18
Q

What happens to the intraabdominal portions of the umbilical vessel after birth?

A

they degenerate

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19
Q

What do the umbilical arteries become after birth?

A

lateral ligaments of the bladder

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20
Q

What does the umbilical vein become after birth?

A

round ligament of the liver.

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21
Q

From the left portal vein, the umbilical blood flows either through the ______ to the systemic veins bypassing the liver or through the ________ to the right portal vein.

A

ductus venosus,

right portal sinus

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22
Q

The _________ forms the conduit between the portal system and the systemic veins

A

ductus venosus

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23
Q

The ductus venosus is ____ during fetal life

A

patent, after birth it becomes the ligamentum venosum

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24
Q

The umbilical arteries run along which margin of the fetal bladder?

A

lateral margin

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25
Q

In the post partum stage, what do the umbilical arteries become?

A

superior vesical arteries

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26
Q

In the first trimester, the umbilical cord length should be the same as what?

A

crown-rump length

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27
Q

A long umbilical cord measures greater than

A

80 cm

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28
Q

What may long umbilical cords be associated with or predisposed to?
Hint: 5 things

A 
Polyhydramnios
Nuchal cord (occurs in 25% of deliveries)
True cord knots
Umbilical cord compression
Umbilical cord stricture or torsion
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29
Q

A short umbilical cord measures

A

less than 35 cm in length

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30
Q

A short umbilical cord is associated with or predisposed to what 7 things?

A 
Oligohydramnios
Restricted space
Intrinsic fetal anomaly
Tethering of the fetus by an amniotic band
Inadequate fetal descent
Cord compression 
Fetal distress
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31
Q

T/F: Coiling of the umbilical cord is normal?

A

True, related to fetal activity

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32
Q

How often may the normal cord coil?

A

40 times, usually to the left and near fetal insertion site

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33
Q

The helical twisting of the cord can be easily determined by

A

gross pathologic inspection

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34
Q

The incidence of a “left” twist of the cord is found in

A

7:1 pregnacies

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35
Q

A fetus with a “right” twist in the cord has a higher incidence of

A

anomalies than one with a left twist

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36
Q

T/F: umbilical cord masses are common

A

False, many “masses” may be attributed to focal accumulation of Wharton’s jelly and may be isolated or associated with an omphalocele or cyst

37
Q

A cystic mass in the cord is usually ______ or _______ in origin

A

omphalomesenteric or allantoic

38
Q

Cysts persisting past the first trimester are associated with :

A

other fetal anomalies and aneuploidy

39
Q

10 masses associated with the umbilical cord are:

A 
Omphalocele
Gastroschisis
Umbilical herniation
Teratoma
Aneurysm
Varix of the cord
Hematoma
True knot
Angioma 
Thrombosis
40
Q

What is omphalocele?

A

Failure of the intestines to return to the abdomen

41
Q

An omphalocele may consist of

A

a single loop of bowel or most of the intestines and/or liver

42
Q

Omphaloceles are completely covered by

A

epithelium from the umbilical cord

43
Q

What is gastroschisis?

A

A right paraumbilical defect involving all layers of the abdominal wall

44
Q

The _____ always eviscerates with gastroschisis.

A

small bowel, but other organs that can possibly eviscerate are large bowel, stomach, portion of GI tract, and liver

45
Q

With gastroschisis, the loops of bowel are

A

NEVER covered by membrane

46
Q

When does umbilical herniation occur?

A

when the intestines return normally to the abdominal cavity and then herniate either prenatally or postnatally through an inadequatley closed umbilicus

47
Q

What is an omphalomesenteric cyst?

A

a cystic lesion of the umbilical cord caused by persistence and dialation of a segment of the omphalomesenteric duct

48
Q

This omphalomesenteric cyst is found closer to the

A

fetal insertion and may vary in size

49
Q

What causes a hemangioma of the cord?

A

the transepithelial cells of the vessels of the umbilical cord

50
Q

Sites of origin of hemangiomas of the cord:

A

main vessels of the cord, may involve more than one.

51
Q

T/F: Hemangiomas of the cord are rare?

A

TRUE

52
Q

Hematoma of the cord is caused by

A

trauma to vessels resulting in blood moving into Wharton’s jelly..usually occuring near the fetal insertion of cord and the umbilical vein is most often involved.

53
Q

What is thrombosis of the umbilical vessels?

A

occlusion of one or more vessels of the umbilical cord

54
Q

Which vessel(s) is the primary location of thrombosis?

A

umbilical vein

55
Q

Thrombosis may be primary or secondary to:

A 
torsion
knotting
looping
compressions
or hematoma
56
Q

T/F: Prognosis is good in the fetus with umbilical vein thrombosis?

A

False, it’s poor

57
Q

True knots of the cord have been associated with

A 
long cords
Polyhydramnios
intrauterine growth restriction
monoamniotic twins
and increased risk of congenital anomalies
58
Q

When are false knots found?

A

When the blood vessels are longer than the cord (often they fold on themselves and produce nodulations on the surface of cord)

59
Q

The most common cord entanglement in the fetus:

A

nuchal cord

60
Q

A single loop of cord has been seen in more than ___% of deliveries, two loops have been found in ___%.

A

20%, 2.5%

61
Q

What issues are seen more frequently with fetuses suffering cord entanglement?

A

fetal heart deceleration
meconium stained amniotic fluid
babies requiring resuscitation

62
Q

Why is a battledore placenta significant?

A

When the cord is inserted near the cervical os, labor may cause the cord to prolapse or be compressed during contractions

63
Q

What occurs when the cord inserts into the membranes before it enters the placenta raither than inserting directly into the placenta?

A

Membranous/Velamentous insertion

64
Q

Velamentous insertion MAY occur when?

A

If most of the placental tissue grows laterally, leaving the initially centrally located cord in an area that becomes atretic.

65
Q

Velamentous insertion is associated with:

A 
Higher risk of low birth weight
Small for gestational age
Preterm delivery
Low Apgar scores
Abnormal intrapartum fetal heart rate pattern
66
Q

When does prolapse of the cord occur?

A

when cord lies below presenting part (may occur whenever the presenting part does not fit closely and fails to fill pelvic inlet

67
Q

Compression of cord may cause

A

fetal demise (lack of blood supply)

68
Q

Abnormal fetal presentation occurs in ____ of prolapse cord cases

A

nearly half

69
Q

10 conditions predisposing to cord presentation and prolapse:

A

Abnormal fetal presentation
Nonengagement of the fetus because of prematurity
Long umbilical cord
Abnormal bony pelvic inlet
Leiomyomas
Polyhydramnios
Vasa previa
Velamentous insertion of the cord
Marginal insertion of the cord in a low-lying placenta
Incompetent cervix with premature rupture of the membranes

70
Q

______ of cord prolapse problems are produced during obstetric procedures

A

One third (1/3)

71
Q

What obstetric procedures can cause cord prolapse?

A

artificial rupture of membranes
disengaging the head
flexion of an extended head
version and extraction

72
Q

What is the best method of detecting vasa previa?

A

color Doppler

73
Q

Define vasa previa

A

presence of umbilical cord vessels crossing internal os

74
Q

What factors may cause vasa previa?

A

velamentous insertion of cord
succenturate lobe
low-lying placenta with marginal insertion near os

75
Q

Single umbilical arteries have been found in __% of pregnancies with marginal insertion and in __% of those with membranous insertion of the cord.

A

18%, 9%

76
Q

Probable cause of single umbilical artery:

A

atrophy of one during early development stage

77
Q

Which umbilical artery is most often missing?

A

Left (just a slightly higher percentage difference)

78
Q

Single umbilical artery is associated with:

A

Congenital anomalies in 20-50% of cases
Increased incidence of IUGR
Increased perinatal mortality
Increased incidence of chromosomal abnormalities

79
Q

Anomalies associated with single umbilical artery that affect other organ systems:

A 
Musculoskeletal
Genitourinary
Cardiovascular
Gastrointestinal
Central nervous system
80
Q

Hypoplastic umbilical artery occurs when

A

a 3-vessel cord shows an artery-to-artery difference of more than 50%

81
Q

What is aneurysm of umbilical vessels?

A

focal dilation of umbilical artery

82
Q

What is varix?

A

focal dilation of umbilical vein

83
Q

How does varix appear sonographically?

A

a dilated intraabdominal, extrahepatic portion of the umbilical vein

84
Q

Prognosis of fetus with varix?

A

normal

85
Q

Typically, by 6 weeks the right umbilical vein

A

regresses and the left umbilical vein enlarges to accomodate the increasing flow

86
Q

When the right umbilical vein does not disappear, this is called:

A

persistent intrahepatic right portal vein (rare and may be related to an involution of the left umbilical vein)

87
Q

If right umbilical vein persists, where will it go?

A

enters the right lobe of liver to join the right portal vein

88
Q

What % of cases of persistent right portal veins have other fetal anomalies?

A

at least 50%

89
Q

Sonographically, what does it look like when the right vein persists?

A

Vein curves toward the left-sided stomach rather than towards the liver

OB Pathology (16 decks)

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