Placenta and umbilical cord Flashcards

1
Q

Placenta is formed by the

A

decidua basalis and decidua frondosum

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2
Q

Physiology of placenta

A
  • vital support organ for developing fetus
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3
Q

major functioning unit of placenta

A

chorionic villus

- contains intervillous space

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4
Q

maternal blood enter the

A

intervillous space

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5
Q

Placenta Functions

Respiration

A
  • oxygen in maternal blood passes through plac into fetal blood
  • co2 returns through the plac to maternal blood
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6
Q

Placental Function

Nutrition

A

pass from maternal blood through plac to fetal blood

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7
Q

Placenta Function

Excretion

A
  • wast products cross from the fetal blood through the plac to maternal blood
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8
Q

Placenta Function

Protection

A

provides a barrier between the mother and fetus, protecting the fetus from maternal immune rejection

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9
Q

Placenta Function

Storage

A

carbs, proteins, calcium, and iron are stored in plac and released into fetal circulation

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10
Q

Placenta Function

Hormone Production

A

produces hCG, estrogenm and progesterone

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11
Q

Plac Size

A
  • varies with gestational age
  • 2-3 mm thickness
  • should exceed 4 cm
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12
Q

Normal sono appearence of placenta in 1st trimester

A

thickened area of hyper gestational age

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13
Q

Normal sono appearence of placenta in 2nd and 3rd trimester

A
  • smooth, homogeneous medium-gray structures
  • smooth border and edges
  • hyperechoic chorion plate
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14
Q

cystic areas directley behind chorion plate

A

fetal vessels

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15
Q

plac may be located

A

ant, post, fundal, rt later, and lt lateral

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16
Q

plac may be implanted over or near

A

cervical os (previa)

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17
Q

grading is dependent on

A

echogenicity attributed to calcium and fibrous deposition with advancing age

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18
Q

cause premature maturation of plac

A

maternal hypertensions, smoking, iugr, multifetal gestation

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19
Q
  • no calcification
  • smooth basal and chorionic plate
  • 1st and early second
A

Grade 0

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20
Q
  • scattered calification throughout the plac

- most common up until 34 w

A

Grade 1

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21
Q
  • calcifications along basal palte

- chorionic plate becomes slightly lobular

A

Grade 2

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22
Q
  • marked calcifications
  • distinct hyper loculations extending from chorionic to basal plate
  • abnormal before 34 w
A

Grade 3

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23
Q
  • in front of fetus relative to birth canal

- primary cause of painless vag bleeding in 3rd trim

A

Plac previa

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24
Q

plac previa risk factors

A

advanced maternal age, multiparity, previous c section, theraputic abortion, or closely spaced pregnancies

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25
Q

plac previa complications

A

premature delivery, life-theratening maternal hemorrhage, increased risk of plac accretta, stillbirth, and iugr

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26
Q

Plac previa complete

A
  • painless vag bleeding

- placenta cover entire cervical os

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27
Q

plac pervia partial/ incomplete

A
  • painless vag bleeding

- placenta covers one side of cervical os

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28
Q

plac previa marginal

A
  • asymptomatic, painless vag bleeding

- edge of plac covers one side of the cervical os

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29
Q

plac previa low-lying

A
  • asymptomatic
  • painless vag bleeding
  • edge of plac lies close by doesnt abut cx os, 2 cm
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30
Q

plac vasa previa

A
  • bleeding
  • cord compression
  • prolapsed cord
  • transverse fetal lie
  • fetal vessels cross over internal os
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31
Q

Plac abruption

A
  • premature plac detachment

- clinical findings include severe pelvic pain and vag bleeding

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32
Q

plac abruption risk factors

A

materal hypertension, smoking, diabetes, trauma, plac previa, and short umbilical cord

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33
Q

plac abruption sono findings

A
  • hypoechoic retroplacental mass
  • plac thickening
  • well defined margins
  • sub amniotic or preplacental locations are rare
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34
Q

plac accreta

A
  • chorionic villi of the plac are indirect contact with uterine myo
  • attributed to complete or partial absence of the decidua basalis
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35
Q

plac accreta risk factors

A

multiparity, plac previa, and previous c section

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36
Q

plac accreta sono findings

A
  • obscured or absent retroplacental complex

- numerous plac lakes

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37
Q

plac increta

A
  • plac invades the uterine myo
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38
Q

plac increta sono findings

A

extension of villi into myo

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39
Q

plac percreta

A

placental vessels invade uterine serosa and bladder

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40
Q

plac percreta sono findings

A

extension of villi outisde of ut

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41
Q

amniochorionic seperation

amnion

A

separated from fetal surface of plac but cant separate from umbilical insert site

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42
Q

amniochorionic seperation

chorion

A

separated from endo lining but cant separate from plac edge

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43
Q

amnionchorionic separation

A
  • localized fluid between fetal side of plac and amniotic membrane
  • membrane can move
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44
Q

Battledore plac

A

cord insert into end margins of plac

45
Q

battledore plac sono findings

A

insertion of cord into end margin of plac

46
Q

calcifications

A
  • sign of mature plac

- assoc with smoking or thrombotic disorders

47
Q

calcification sono findings

A
  • hyper focus within the plac tissue

- posterior shadowing

48
Q

circumvallate plac

A
  • abnormal plac shape in which membrane insert away from plac edge toward center
  • increase risk for sbruption, iugr, premature labor, perinatal death
49
Q

fibrin deposits

A
  • more commonly located along the subchorionic region of plac
  • attributed to regulation of interbillous circulation
50
Q

fibrin deposits sono findings

A
  • hypo area beneath chorionic plate of plac

- traingular or rectangle in shape

51
Q

intervillous thrombosis

A
  • presence of thrombus within the intervillous space
  • occurs in 1/3 pregnancies
  • little risk to fetus
52
Q

intervillous thrombosis sono findings

A
  • anechoic or hypo intraplacental mass

- nonvascular

53
Q

placental infarct

A
  • results of ischemic necrosis
  • occurs in 25% of pregnancies
  • no clinical risk when small
54
Q

placental infarct sono findings

A
  • hypoechoic focal placental mass

- calcification may occur

55
Q

placental lakes sono findings

A
  • anechoic area with internal blood flow
56
Q

placentomalacia

A
  • small plac
  • iugr
  • intrauterine infection
  • chromosomal abnormalities
57
Q

placentomegaly

A
  • primary causes include maternal diabetes and rh sensitivity
  • assoc with maternal anemia, twin-twin transfusion, fetal anomalies and intrauterine infection
58
Q

placentomegaly sono findings

A
  • max thickness > 5 cm
  • heterogeneous texture assoc with tripoloidy, molar pregnancy, or hemorrhage
  • homogeneous texture assoc with anemia, hydrops, and eh sensitivity
59
Q

succenturiate plac

A
  • results of the lack of adj chorionic villi to atrophy
  • approx 5% pregnancies
  • increased risk of velamentous cord and vasa previa
60
Q

succenturiate plac sono findings

A
  • additional plac tissue adh to main plac

- connected to body of plac by blood vessels

61
Q

Chorioangioma

A
  • placental hemangioma
  • arises from chorionic tissue of amniotic surface of plac
  • fetaus demonstrates distress owing to vascular shunting from normal lac to hemangioma when large
62
Q

choriangioma metastases to

A

lung, spleen, kidney, intestines, liver and brain

63
Q

chrioangioma sono findings

A
  • enlarge plac
  • circular, solid hypo mass protruding from chorionic plate
  • usually occur at umb insert
  • poly, hydrops, iugr
64
Q

choriocarcinoma

A
  • malignant form of trophoblastic disease

- 50% are preceded by a molar pregnancy

65
Q

choriocarcinoma sono findings

A
  • hypo intraplac mass
66
Q

gestational trophoblastic disease

A
  • molar pregnancy
  • complete molar pregnancy may cevelop into choriocarcinoma
  • partial mole carries little malignant potential
67
Q

Gestational trophoblastic disease sono findings

A
  • inhomogeneous uterine texture
  • various sized cystic structures within plac
  • coexsist with decrease in afi
68
Q

Umbilical cord normally inserts into

A

the center of the plac and midline of anterior abd wall of fetus

69
Q

Umbilical vein carries

A

oxygenated blood

70
Q

umbilical arteries return

A

venous blood back into plac

71
Q

Umbilical cord is formed by the

A

fusion of the yolk sac and body stalk (allantoic ducts)

72
Q

What covers the umbilical cord and blends into the fetal skin at the umbilicus?

A

amniotic membrane

73
Q

Wharton’s jelly

A

composed of one vein and two arteries surrounded by myxomatous connective tissue

74
Q

Umbilical Vein

A
  • formed by the confluence of chorionic vein of plac

- enters umbilicus and joins the left portal vein of liver

75
Q

Umbilical Arteries

A
  • contiguous with hypogastic arteries on each side of the bladder
  • exits umbilicus
  • return venous blood from the fetus back to the plac
  • demonstrate low resistance blood flow with continuous diastolic flow
76
Q

length of umbilical cord in 1st trim equals

A

crown rump length

77
Q

length during second and third trim

A

40-60 cm

78
Q

Diameter of the umbilical cord

A
79
Q

Umbilical vein diameter

A
80
Q

cyst of umbilical cord

A
  • normal findings in 1st trim

- 50% of cases assoc with fetal anomalies in 2nd and 3rd trim

81
Q

cyst of umbilical cord sono appearence

A
  • nonvascular anechoic enlargement
82
Q

false knot of umbilical cord

A

coiling of blood vessels, giving the appearance of knots

83
Q

false knot of umbilical cord sono findings

A

blood vessels folding over on themselves mimicking umbilical nodules

84
Q

long cord

A

-cord >80 cm

85
Q

long cord sono findings

A

nuchal cord
poly
true umbilical cord knot
vasa previa

86
Q

nuchal cord

A
  • cord completely surrounds fetal neck with more than one loop
  • fetus will turn in and out of umbilical cord throughout the pregnancy
87
Q

nuchal cord sono findings

A
  • two or more complete loops of cord around neck

- flattening of cord

88
Q

prolapsed cord

A

cord preceds the fetus in the birthing process

89
Q

prolapsed cord sono findings

A

presence of cord before shortthe presenting fetal part

90
Q

short cord

A
91
Q

short cord sono findings

A
  • limited fetal movement
  • inadequate fetal descent
  • cord compression
  • oligo
92
Q

single umbilical artery is more common in

A

multiple gestations

93
Q

single umbilical artery demonstrates

A

both single and double umbilical arteries within same cord

94
Q

single umbilical artery increases risk of

A

assoc fetal anomalies and iugr

95
Q

single umbilical artery is assoc with

A

malformations of all major organ systems and chromosomal anomalies

96
Q

single umbilical arteries sono findings

A
  • two vessels of similar size within umbilical cord
  • umbilical artery transverse dia >4 mm
  • straight, noncoiled
97
Q

Thrombosis of umbilical vessels

A
  • primarily vein

- higher incidence in diabetic mothers

98
Q

thrombosis of vessels

A
  • absent or abd flow

- hypoechoic enlargement of 1 or more vessels

99
Q

varix of umbilical vein

A
  • focal dilation of vein
  • always intraabdominal
  • assoc with normal outcomes
100
Q

varix of umbilical vein sono findings

A
  • intraabdominal focal dilation of vein

- located between anterior abd wall and liver

101
Q

velamentous cord insert

A
  • umbilical cord insert into membranes before entering the plac
  • not protected by Wharton’s Jelly
102
Q

velamentous cord insert assoc with

A
preterm labor
abnormal fetal heart pattern
low apgar scores
low birth weight
iugr
103
Q

velamentous cord insert sono findings

A

insert of umbilical cord into membrane adj to edge of plac margin

104
Q

incompetent cervix

A
  • cervical shortening

- painless

105
Q

decrease in cervical length of > 6mm

A

increases risk of preterm labor

106
Q

incompetent cervix risk factors

A

multiple pregnancies
hx of premature labor
previous hx of cervical surgery

107
Q

incompenent cx cervical length

A
108
Q

dilating of cervical os

A

> 3 - 6 mm

109
Q

incompenent sono finding

A

funneling of amniotic fluid into cervical canal