Obstetrical Sonography 2 - PowerPoint Presentation

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Obstetrical Sonography 2Chapter 19: The placenta and Umbilical cord hhholdorfSlide2

Outline - PlacentaPlacental folklore

Normal placenta

Placental grading

Placental variants

Accessary types

Placental infarcts

Maternal lakes

Subchorionic hematomas

Placental previa

Abnormal adherence

Placental tumorsSlide3

Outline – umbilical cordUmbilical cordSUA

Umbilical cord cysts

Nuchal cord

Umbilical venous thrombosis

Velamentous insertion

Short umbilical cordSlide4

Placenta Rituals and Folklore from around the WorldThe newborn baby’s placenta is the focus of many post-birth rituals around the world. As well as honoring the baby’s placenta, these practices spiritually safeguard baby and mother during the major transitions of birth and the postnatal period.Slide5

In Cambodia, for example, the baby’s placenta, which traditional Cambodian healers call “the globe of the origin of the soul,” must be buried in the right location and orientation to protect the baby. The burial place may be covered with a spiky plant to keep evil spirits and dogs from interfering, because such interference could have long-term effects on the mother’s mental health. People have described wrapping the newborn placenta in paper, burying it in a dry hole, then covering it with ashes from the stove. This ritual protects the mother from retained blood clots, cramps, and infection.Slide6

The influence of the child’s placenta and cord is, in many places, thought to extend long after birth. In Turkey, the placenta, which is known as the friend or comrade of the baby, is wrapped in a clean cloth and buried. The cord, however, may be buried in the courtyard of a mosque, if the parents wish their child to be devout in later life. Similarly, if the parents want their child to be well educated, they may throw the cord over a schoolyard wall. Slide7

For the Navajo, burying a child’s placenta within the four sacred corners of the reservation ensures that he or she will be connected with the land and will always return home.In Cambodia, children are safe as long as they don’t stray too far from where their placentas are buried.

The placenta has also been recognized as a source of power and magic. An Egyptian pharaoh was preceded in procession by his actual placenta, fixed to the end of a pole.

Many symbols of leadership and status are derived from birth—for example, the crowning of a monarch may be derived from “crowning at birth,” and the caduceus—the wand of Hippocrates entwined by two snakes, and the symbol of the medical profession—is derived from the triple-vesseled umbilicusSlide8

In traditional Ukrainian culture, a midwife would derive from the newborn placenta how many more children the mother would bear. The placenta was later buried where it would not be stepped over—if it were buried under the doorway, the mother would become infertile.

In Japan, however, a childless woman who desired pregnancy would borrow the petticoat of a pregnant friend and deliberately step over a baby’s newly buried placenta.

In Transylvania, a couple who desired no more children would burn their baby’s placenta and mix it with ashes. The husband would then drink this to render himself infertile.Slide9

The placenta is held in reverence and awe because it accompanies the child from the spirit or womb world. For the Hmong, it must also accompany the person back to the spirit world. After death, a Hmong must travel back to every place the person has lived until they reach the burial ground of their placenta. Only when clothed in their placental “jacket” (the Hmong word for placenta also means jacket) can the soul travel on to be reunited with the ancestors, then be reincarnated in the soul of a new baby. If the soul cannot find its placental jacket, it will be condemned to wander forever naked and alone.Slide10

THE PLACENTANormal:

• Highly vascular

• Provides nutrition to the fetus.

• 2-4cm thick and weighs 600 grams.

• Divided into two portions:

o

Maternal portion

: less than one-fifth placental weight. Composed of compressed sheets of decidua basalis, divided into grooves (cotyledons)

o

Fetal portion

: units called villi that provide the transfer of metabolic products. Surface covered by amniotic membrane.Slide11

A normal sized placentaSlide12

Placentomegaly An increase in placental thickness. The maximum thickness considered normal at any stage in pregnancy is often taken at 4 cm.

Associations

Maternal diabetes

Chronic inter-uterine infections

Fetal umbilical vein obstruction

Hydrops Fetalis

Chromosomal abnormalitiesSlide13

PlacentomegalySlide14

The maternal portion of the placenta is compressed sheets of decidua basalis. It is divided into cotyledons.The fetal portion of the placenta is chorionic villi, which project into pools of maternal blood know as inter-villous spaces. The fetal surface of the placenta is covered by the amniotic membrane.Slide15

Maternal and fetal portions of the placentaSlide16

Placental grading:• Grade 0-3• The identification of grade III in the second or early third trimester may indicate impending placental insufficiencySlide17

Grade 0Slide18

Grade 0Late 1st trimester-early 2nd trimester Uniform moderate echogenicity

Smooth chorionic plate without indentations Slide19

Grade oneSlide20

Grade 1Mid 2nd trimester –early 3rd trimester (~18-29 weeks) Subtle indentations of chorionic plate

Small, diffuse calcifications (hyperechoic) randomly dispersed in placenta Slide21

Grade twoSlide22

Grade 2Late 3rd trimester (~30 weeks to delivery) Larger indentations along chorionic plate

Larger calcifications in a “dot-dash” configuration along the basilar plate Slide23

Grade threeSlide24

Grade 339 weeks – post dates

Complete indentations of chorionic plate through to the basilar plate creating “cotyledons” (portions of placenta separated by the indentations)

More irregular calcifications with significant shadowing

May signify placental dysmaturity which can cause IUGR

Associated with smoking, chronic hypertension,diabetes Slide25

Placental variantsExtra-chorial types: chorion does not extend to the edge. Two types:

1. Circumvallate: a small, central chorionic ring surrounded by thickened amnion and chorion.

2. Circummarginate-central attachment of membranes without a central ring.Slide26

Circumvallate placenta is a placental disease in which the fetal membranes (chorion and amnion) "double back" on the fetal side around the edge of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface.Slide27

Complications associated with Circumvallate Placenta include:Placental abruption: Premature separation of the placenta, causing significant third trimester bleeding.

Intrauterine growth restriction of the fetus.

Miscarriage.

Pre-term birth.

Oligohydramnios: Decreased amount of amniotic fluid that helps to cushion the fetus.Slide28

CircumvallateSlide29

CircummarginateCircummarginate Placenta is a variation in the normal shape of the

placenta

, characterized by the thinning of membranous tissue on the fetal side.

The condition has no clinical significance.Slide30

CircummarginateSlide31
Slide32

Accessory types:Succenturiate-an accessory cotyledon with vascular connections to the main placenta

Bipartite

: a placenta divided into two lobes but united by primary vessels

Annular

-a ring-shaped placentaSlide33

SuccenturiateSlide34

The Succenturiate lobe of placenta is connected to the main placenta by a string of blood vessels Slide35

Bipartite / bilobed placentaSlide36

Bilobed Slide37

Annular PlacentaA placenta that extends like a belt around the interior of the uterus. AKA: Zonary placentaSlide38

Annular Placenta: The fetus passed through during deliverySlide39

Placenta infarcts•Anechoic or hypoechoic areas seen in the placenta

•May be small or very large

•Absence of blood flow using color or spectral DopplerSlide40

A word about SynechiaeAsherman's syndrome

is a condition characterized by adhesions and/or fibrosis of the endometrium particularly but can also affect the myometrium.

It is often associated with dilation and curettage of the intrauterine cavity.

A number of other terms have been used to describe the condition and related conditions including:

intrauterine adhesions

(IUA),

uterine

/

cervical atresia

,

traumatic uterine atrophy

,

endometrial sclerosis

, and

intrauterine synechiae

.Slide41

Intrauterine synechieSlide42

Placental InfarctPlacental infarction (sometimes called placental cerebral infarction) is the interruption in blood flow between the placenta and the baby. Minor infarctions (lesions or masses on the placenta) are present in about a quarter of all normal pregnancies, and do not affect the pregnancy. More serious infarctions, however, can directly cause fetal distress and long-term complications, including developmental delays and cerebral palsy. Infarctions are typically detected by ultrasound.Slide43

Placental InfarctsSlide44

Placental insufficiencyTwo possible placental changes that may result in placental insufficiency are inter-villous thrombosis and placental infarcts

Sonographically, infarcts they may appear:

Focal anechoic or hypoechoic lesions

may be small or quite large

There is absence of blood flow using spectral or color DopplerSlide45

Placental insufficiency- Doppler InvestigationSlide46
Slide47

Maternal LakesThe presence of large pools of maternal blood within the placenta. May be caused by an early intervillous thrombosis or peri-villous thrombosis.Slide48

Maternal lakesSlide49

Subchorionic (Submembranous) Hematomas •An accumulation of blood beneath the chorion.

•Usually decreases in size on follow-up exam

•May be seen as early as 9 weeks

Differential Diagnosis:

Subchorionic hematoma vs. Twin pregnancySlide50

Subchorionic (Submembranous) Hematoma Slide51

Placenta PreviaImplantation of the placenta such that there is partial or complete coverage of the maternal cervical os.

May result in an obstruction to the descent of the presenting fetal part, as well as difficulties with delivery.

Maternal risk of vaginal bleeding.

Risk factors include previous C-section, advanced maternal age, and smokingSlide52

TYPES:Complete-covering the entire internal os

Partial

Low lying

Lateral

Vasa previa: clinically serious. A Velamentously inserted cord vessels precede the presenting fetal part and overlie the cervix.Slide53

Clinical signs include spotting, sudden painless bleeding in third trimester and Occasional mild cramping

Sonographic findings are placental tissue seen covering or encroaching the internal cervical os.

PITFALLS: over-distended urinary bladder may compress lower uterine segment and focal myometrial contraction.Slide54

CompleteSlide55
Slide56

Patients who have had a previous C section, who are of advanced maternal age, or who smoke cigarettes are at risk for developing placenta previa.

Clinically, placenta previa presents with:

spotting during the 1

st

and 2

nd

trimesters

Sudden, painless profuse bleeding in the 3

rd

trimester

occasional mild cramping

The sonographic pitfalls for misdiagnosing a placenta previa include:

Over-distending the maternal urinary bladder compressing eh LUS

A focal myometrial contraction may also compress the LUS, causing a low placenta to look like a previa.Slide57

Vasa previa occurs when one or more of the placental or umbilical blood vessels cross the entrance to the birth canal beneath the fetus. Slide58

Abruptio PlacentaePremature separation of the placenta from the uterine wall.Predisposing conditions may be hypertension, preeclampsia.Slide59

Bleeding occurs in the two types of abruptions:Concealed: 20% of cases: The hemorrhage is confined to the uterine cavity. Detachment may be complete and the consequences are severe.

2. External: Blood drains through the cervical os. Clinically very painful vaginal bleeding. Detachment is usually not as severe.Slide60

Clinical signs:• Abdominal pain• Hemorrhage may be visible• Evidence of fetal distress• Hypovolemic shock

• TraumaSlide61

Sonographic findings•Elevation of the placenta from the uterine wall•Retroplacental sonolucent or complex mass without flow by DopplerSlide62

Abruptio PlacentaeSlide63

A placental abruption is the premature separation of the placenta from the uterine wall.The following conditions predispose a patient t placental abruption:

Hypertension

Pre-eclampsia

Diabetes

Chronic renal disease

IVC compression

Vaso-dilation secondary to shock

Clinically, placental abruption presents with:

abdominal or uterine pain

a spastic uterus

vaginal hemorrhage

disseminated intravascular coagulopathy (DIC)

TraumaSlide64

Abnormal AdherenceThe villi may adhere to the myometrium.

A total hysterectomy may be necessary.

1. Placenta Accreta-placental villi attached to myometrium but do not invade

2. Placenta Increta-Deep invasion of the myometrium

3. Placenta Percreta-Perforation of the myometrium by invading placental tissueSlide65

Associated with increased morbidity and mortalityAssociated with maternal hemorrhageSonographic diagnosis is difficultSlide66

Diagram of abnormal placental adherenceSlide67

The placenta villi may abnormally adhere to the myometrium, classified by their degree of extension:Placenta Accreta-villi attach to the myometrium but do not invade itPlacenta Increta-villi deeply invade the myometrium

placenta Percreta-villi perforate the myometrium and extend beyond (sometimes into the maternal bladder)Slide68
Slide69

The fertilized ovum normally implants in the uterine fundus. The last slide diagrammatically illustrates several problems that can occur with placentation:

SEE DIAGRAM ON NEXT SLIDE:

a

. Normal placenta.

b

. Placenta previa results from a very low lying placenta or a placenta which cover the os. Obviously, severe hemorrhage can result with cervical dilation and passage of the baby through the birth canal.

c

. Placenta accreta results from a lack of formation of a normal decidual plate. Thus, the chorionic villi extend into myometrium, and the placenta cannot separate normally following delivery. Severe hemorrhage results.

d

. Abruptio placenta results from premature separation of the placenta prior to delivery, with formation of a retroplacental blood clot. The blood supply of oxygen and nutrients to the fetus is compromised to a greater degree with increasing size of the abruption.Slide70

Placenta abnormalities Slide71

Placental tumorsChoriocarcinoma

Malignant trophoblastic cancer, usually in the placenta.

Chorioangioma

Considered the most common primary tumor of the placenta

Usually occurs near the insertion of the umbilical cord and protrudes into the amniotic cavity.

Vascular shunting may cause fetal high-output cardiac failure and hydrops fetalis.Slide72

Choriocarcinoma

Choriocarcinoma is a type of cancer that develops in the uterus. In choriocarcinoma, the placenta that begins to form during pregnancy is replaced by a rapidly growing abnormal tissue. The cancer is highly malignant, in which the abnormal cells multiply and spread rapidly to the other organs of the body, especially the lungs.Slide73

ChorioangiomaSlide74

Large chorioangiomas (>5cm) may cause complications such as Polyhydramnios or fetal hydrops.Slide75

The umbilical cordSlide76

UMBILICAL CORDContains two arteries and one vein that transports blood between the fetus and the fetal portion of the placenta.

Length is about 55cm.

Vessels are surrounded by Wharton’s Jelly and the entire cord is covered by amnion.Slide77

The umbilical vein has oxygen!!!!The

umbilical vein

is a vein present during fetal development that carries oxygenated blood from the placenta to the growing fetus.

The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the chorionic villi

. More than two-thirds of the blood enters the liver from its inferior border, while the remainder is shunted to the inferior vena cava through the ductus venosus and is delivered to the fetal right atrium.Slide78

The Umbilical artery has no oxygen!!!The umbilical arteries supply deoxygenated blood from the fetus to the placenta. There are usually two umbilical arteries present together with one umbilical vein in the umbilical cord.

The umbilical arteries surround the urinary bladder and then carry all the deoxygenated blood out of the fetus through the umbilical cord.

Inside the placenta, the umbilical arteries connect with each other at a distance of approximately 5 mm from the cord insertion.Slide79

The money shot- three vessel cordSlide80

The less-money shot- the 3vcSlide81

SUAReferred to as a two vessel cord.Causes include Primary agenesis of one of the arteries, Secondary atrophy of a previously present artery, or persistence of the original, single embryonic artery.Slide82

By itself, SUA is not bad. However, SUA may be associated with other fetal anomalies. Associated abnormalities include:

1. Trisomy's 13 and 18

2. GU anomalies

3. CNS anomalies

4. Cardiac anomalies

5. Omphalocele

6. Sirenomelia

7. VACTERL syndrome

AKA VATER: Vertebral defects, anal atresia, Cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities.Slide83

Findings include: Absence of an umbilical arteryTwo vessel cordWhen present, an examination of the fetal anatomy must be performedSlide84

Two Vessel CorD (SUA)Slide85

svcSlide86

Umbilical cord cystsOmphalomesenteric Duct Cyst: A cystic lesion of the umbilical cord due to the presence and dilatation of the embryonic omphalomesenteric duct.

Cysts are generally located close to the fetus and can be large or small.

Allantoic Cyst

Usually small and located within the cord away from the fetal abdomen.Slide87

Allantoic duct cyst: causes cord swellingSlide88
Slide89

Umbilical cord cystSlide90

NUCHAL CORDThe wrapping of the umbilical cored around the fetal neck. Occurs in about 25% of deliveries and is rarely associated with fetal complications.

3 or more “wraps” constitutes a true nuchal cordSlide91

Nuchal CordSlide92

Umbilical Venous ThrombosisTorsion, knotting or compression of the umbilical cord may cause venous stasis and ultimately thrombosis.Slide93

Umbilical cord torsion can lead to fetal deathSlide94

Umbilical cord knottingSlide95

Velamentous Insertion of CordAttachment of the cord to the membranes rather than to the placental mass.

Velamentous vs. marginal insertion: the cord travels beneath the chorion for some distance before attaching to the edge of the placenta in Velamentous insertion.

This may be associated with IUGR, Preterm birth and congenital anomaliesSlide96

Velamentous Insertion of CordSlide97

Short umbilical cordSlide98

Short umbilical cord: Possible consequencesApproximately 6 percent of infants are delivered with a short umbilical cord. This condition has been associated with several abnormalities during pregnancy and complications of labor and delivery, but little is known about the etiology of short cord or its associated complications.

AKA: Body Stalk anomalySlide99