ABNORMALITY OF PLACENTA Flashcards
Placenta size and thickness
15-20 diameter
< 4 cm thickness
Discoid shape
Short umblicalcord cause
Traction during labor
And delivery
Tearing of cord
Abruption
Inversion of uterus
Long umbilical cord
Prolapse
nuckalcord
Tie in true knots
Fibrin deposit in placenta
In the floor of placenta
Increase mechanical stability
More flow =î fibrin deposit
Regulation of intervillous circulation
Us of fibrin deposit
Subchorionic
Hypeechoic areas under the chorionic plate of the placenta
Differential diagnosis of fibrin deposition
Venous lake slow flow with real time sono
Subchorionic hematoma
Placenta size
Placentoemegaly
Small placenta
Small placenta
Iugr
Intrauterine infection
Aneuploidy
Placenta previa
Implantation of placenta over internal cervical os
Normally in body or fundus
Î risk of placenta previa
History of cesarean
Types of previa
Complete previa
Partial
Marginal
Low-lying
Factors associated with previa
Maternal age
Smoking
Cocaine abuse
Prior placental previa
Multiparity
Cs
Uterine surgery
Clinically placenta previa
Painless
Originated vaginal bleeding in third trimester
20% with uteri focal myomertrial contraction
Abnormal lie with placenta previa
Vasa previa
Large feral vessels run in feral membranes across cervical os
Vasa previa complication
Life threatening hemorrhage
Vessels at risk of rupture
Most common cause of vasa previa
Relameníous insertion of umblical cord into placental membrane
Which cross over the cervix
Vasa previa can result in
Exsanguination of fetus
Placental invasion
Abnormal penetration of placental tissue beyond endometrial lining of uterus
Variants of placenta invasion
Placenta accrete
Increta
Percreta
Complication of placental invasion
High maternal mortality with placenta
Increta
percreta
Placental invasion results from
Underdeveloped decidualized of endometrium
Association of placenta previa cause thin dearly formed deciduas of the lower uterine segment little resistance to deeper invasion by the thropheblast
Succenturiate placenta
One or move accessory lobes connected of to body placenta by placental vessels
Bilobed placenta
The two lobes of the placenta are separated by a thin bridge of placental tissue that covers the internal os
Card inserts into the bridge of tissue
Circumvallate/ circummarginata placenta
Attachment of placental membrane to feral surface of placemat rather than to underlying villous placental margin
The feral surface( chorionic plate)
Is smaller than the basal cause rolling and shoulderingthe placental margins
Circumvallate placenta is diagnosed when
Placental margin folded
Thickend
Elevated with fibrin and hemorrhage underlying
Circumvallate placenta associated with
PROM
Preterm laboR
IUGR
Placental abruption
Placental hemorrhage
Bleeding from placenta from any cause
More commonly seen than placental abruption
Placental hemorrhage
Locations of placental hemorrhage
Retroplacental
Subchorionic
Sub amniotic
Intraplacental sites
Placental hemorrhage echogenicity
Depends on age of hemorrhage
Acute bleeding similar echogenicity placenta
Echogenic
Subacute and chronic bleed more hypoechoic
Placental abruption
Separation of normally implanted placenta prior
To term delivery
Premature placental detachment
Bleeding in residua basalis occurs with separation
Types of placental abruption
Retroplacental
Marginal
Highpressure breed abruption
Retroplacental abruption
Rupture E of spiral arteries
Retroplacenian abruption associated with
HTN
Vascular disease
May have no vaginal bleeding
If blood remains Retroplacental
Hematoma is btw placenta and uterus
US in retroplacental abruption
Thickening of placenta
Older hematoma hypoechoic compared to placenta
Separation of placenta from uterine wall
Visual sonographic club in Retroplacental abruption
Thickening of placenta
Separation of placenta from uterine wall
Marginal abruption
Hemorrhage from tears of marginal veins
Most common type of abruption
Marginal abruption
Law pressure bleed
Marginal abruption
Tears of marginal veins
Arise from age of placenta
With little placental detachment
Intervillous thrombosis
Presense of thrombus within intervillous spaces
Intraplacental hemorrhage by villus capillaries
US of intervillous thrombosis
Sono lucena areas within the texture of the placenta
Placenta infarcts
Focal discrete lesion caused by ischemic necrosis
Usually small/ no Clinical significance
Maybe unable todistinguish placenta infarcts with
Intraplacental hemorrhage
Hypoechoic in acute stage
Placenta infarcts stages:
Acute. Hypoechoic
Subacute
Chronic
Calcification over time
Placental tumors
Gestational trophoblastic disease
Chorioangioma
Gestational trophoblastic disease
Originate in placenta
Benign or malignant
Gestational trophoblastic disease types:
Complete or partial male
Choriocarcinoma
Invasive mole
Complete mole karyotype
Diploid karyotype
No fetal tissue
Gestational trophoblastic disease clinical symptoms
Nasca and vonmiting î hCG
Vaginal bleeding
Uterine size larger than dates
Partial or incomplete maoles karyotype
A triploid karyotype
Feral tissue is often present
US of a hydatiform mole
Multiple tiny vesicles throughout of the uterine cavity
Thickend placenta with cystic changes is seen
Chorioangioma
Benign vascular tumor of placenta
Most common rumor of placenta
Chorioangioma
Usualy small
Benign proliferation of fetal vessels that arise beneath chorionic plate
Chorioangioma
Large Chorioangioma tumors,act as
Act as arteriovenous malformations
Shunting blood from fetus
Feral complication in large Chorioangioma
Polyhydramnious
Hydros
Anemia
Cardiomegaly
IUGR
Demise
Clinical symptoms in large Chorioangioma
Î AFT in maternal serum on in AF
Chorioangioma in US:
Hypeechoicmass
Compared with the normal placenta
Vascularity with cover Doppler
Di/Di cariotype
Dizygotic, 97%
Or in mono zigotic when division ocurres in first 4 days
Risk involved in monochorionic
Placental vascular anastomosis
Risk involved in monoamniotic
Entanglement of umbilical cord
Placental location options
Anterior
Posterior
R or L Lateral
Fundal
Normal location of placenta for pregnancy greater than 16 weeks
Placemat age is 2cm or more from the internal os
Low-lying placenta
Placental edge less than 2 Cm from internal os but not covering internal os
Follow up at 32 weeks of gestation
Placenta previa location
Placental edge covers the internal os
Follow up at 32 weeks
At 32 weeks placental fallow up if
The placental edge is less than 2cm from the internal osv(low - lying) or covering the cervical (placenta previa)
Follow up TV Sono at 36 weeks of gestation
What happened if vasa previa not diagnosed prior to birth
The fetal death rate high as 60%
Prominent vessel overlying the cervix how to differentiate eather feral or Mam
On color doppler
And spectral tracing arterial flow and heart rate if high it is fetal vessel
The important thing in patient with an anterior placenta that is low lying or previa
Is knowing
Has the patient had a C section before
Once find at risk patient
Look for robust color flow
Cystic change in the placenta
Marked thin Ning
Of the anterior myometrium
Average thickness of a normal placenta
2-4 cm
Accurate measurement of placenta
In the middle portion of the placenta near the umbilical cord insertion in cases of central or near central cord insertion
Perpendicular to the uterine wall
From sub placental veins the to amniotic fluid
Excluding the myometrium
Circumvallate placenta.
(a) Longitudinal gray-scale US image at 21 weeks gestation shows the raised edge of the placenta (P) as a linear band of tissue or shelf-like structure (arrow) that may mimic a uterine synechia.
(b) Photograph of a gross specimen from another patient shows the doubled-back fold in the membranes at their attachment (black arrows) near the margins of the placental fetal surface.
Circumvallate
Circumvallate
placenta. Cine US clip through the placenta shows a thick shelflike linear band on both sides of the placenta, which is due to a circumvallate placenta.
Accurate measurements placenta
Accurate measurements should be done in the midportion of the placenta near the umbilical cord insertion in cases of central or near-central cord insertion, and must be measured perpendicular to the uterine wall from the subplacental veins to the amniotic fluid, while excluding the mvomerritor
Placental Cord Insertion
(a) Longitudinal color Doppler image at 20 weeks gestation shows placental cord insertion (CI) near the margin of the placenta (P) within 2 cm of the placental edge (arrow).
Vasa Previa
At gray-scale US, vasa previa appears as linear echolucent structures crossing
Color Doppler US is the imaging modality of choice and shows vascular structures overlying the internal cervical os with a fixed position during maternal repositioning
Spectral waveforms obtained with Doppler US demonstrate fetal-type flow (with a fetal heart rate) within these vessels
Placental Cysts
Chorionic plate cyst.
Longitudinal color Doppler image at 23 weeks gestation shows a well-defined anechoic avascular structure (arrow) along the fetal surface of the placenta (P), which represents a chorionic plate cyst.
Placental Abruption and Associated Hematomas
Subchorionic (preplacental) marginal abruption
hemorrhage. Oblique gray-scale
US image at 32 weeks gestation shows a large heterogeneous crescentic hemorrhage (arrows)
between the surface of the placenta (P) and the membranes, highly consistent with subacute hemorrhage.
Intraplacental hematoma
Longitudinal gray-scale US image at 27 weeks gestation shows a thick heterogeneous placenta (arrows), which is due to a combination of placental tissue and a large isoechoic acute hematoma.
Difference between intraplacenta Hemmorage and lacunae
(b) Placental lacunae. Longitudinal gray-scale
US image of another patient at 29 weeks gestation shows multiple hypochoic areas (arrowheads) representing placenta lacunae.
These had slow blood flow (not shown).
Hemmorage is isoechoic or hyperechic in placenta
Placenta increta
(c) Increased vascularity. Longitudinal color Doppler image of placenta increta in another patient at 23 weeks gestation shows increased intraplacental and retroplacental vascularity (arrows).
Loss of bladder-uterine serosal interface.
Sagittal gray-scale US (d) and color Doppler (e) images of another patient at 28 weeks gestation show bulging (arrows in
d) of the placenta (P) and bladder, with increased chaotic vascularity along the interface (arrowheads in e).
Placenta percrita
Placenta percreta. Sagittal cine
US clip through the lower uterine segment demonstrates features of placenta percreta,
including multiple lacunae,
irregular vessels at the interface with the bladder,
Rubdame
and bulging and extension anteriorly through the lower uterine segment into the bladder wall.
Gestational Trophoblastic Disease
Complete molar pregnancy
(a) Longitudinal gray-scale US image shows expansion of the endometrial cavity by a multicystic mass (arrows)
(snowstorm appearance). No fetal parts can be identified
Kario type 46 diploid
Complete mole with normal fetus in twin
Twin pregnancy with a normal fetus and a complete mole, proven at pathologic examination, at 12 weeks gestation in a patient with a history of in vitro fertilization.
Longitudinal gray-scale US image shows a normal fetus (F) and normal placenta (P) in one gestational sac and an abnormally thick placenta (TP) with multiple cysts (arrows) in the other gestational sac; the latter represents a complete molar pregnancy. No normal fetal parts are seen in this gestational sac.
Placental Nontrophoblastic Tumors
Chorioangioma at 32 weeks gestation. (a) Longitudinal color
Doppler image shows a well-circumscribed hypochoic mass (black arrows) arising from the fetal surface of the placenta (P)
adjacent to the cord insertion
(CI). It demonstrates internal vascularity and a large feeding vessel (white arrow).
Sonographic Findings.
• On ultrasound examination, this fibrin deposition from hematoma and lacunae venous lake
Sonographic Findings.
• On ultrasound examination, this fibrin deposition (subchorionic) appears as hypochoic areas beneath the chorionic plate of the placenta.
• Differential diagnosis of fibrin deposition includes a venous lake or a subchorionic hematoma.
• A venous lake will have slow flow that can be appreciated with real-time sonography. It may be difficult to distinguish fibrin deposits from a hematoma on ultrasound.
Placentomegaly
• Maternal diabetes
• Maternal anemia
• a-Thalassemia
• Rh sensitivity
• Fetomaternal hemorrhage
• Chronic intrauterine infections
• Twin-twin transfusion syndrome
• Congenital neoplasms
• Fetal malformations
Placentomegaly
• Maternal diabetes
• Maternal anemia
• a-Thalassemia
• Rh sensitivity
• Fetomaternal hemorrhage
• Chronic intrauterine infections
• Twin-twin transfusion syndrome
• Congenital neoplasms
• Fetal malformations
Placenta Previa
- Implantation of placenta over internal cervical os
• Normally Implants in body or fundus of uterus
• In one of 200 pregnancies placenta implants over or near to
Internal os of cervix.
• Risk increases with history of cesarean delivery,
Types of placenta previa.
Complete
Partial
Marginal
Low lying
• Complications of placenta previa
• Complications of placenta previa
• Preterm delivery
• Maternal hemorrhage
• Increased risk of placental invasion
• Increased risk of postpartum hemorrhage
• IUGR
Vasa Previa
• Vasa previa potentially life-threatening fetal complication
• Occurs when large fetal vessels run in fetal membranes across cervical os
• Vessels at risk of rupture and life-threatening hemorrhage
• Most common causes of vasa previa:
• Succenturiate lobe present, and connecting vessels traverse the cervix
• Velamentous insertion of umbilical cord into placental membranes, which cross over the cervix
Placental Invasion
Transvaginal image of placenta and maternal urinary bladder.
Arrows are showing hypochoic vascular lacunae. Curved arrow is pointing at loss of the subplacental hypochoic zone.
Retroplacental Abruption
- Results from rupture of spiral arteries and is “high-pressure” bleed
• Is associated with HT and vascular disease
• Hematoma is between placenta and uter.
• If blood remains retroplacental, patient may have no vaginal bleeding.
Marginal Abruption
• Subchorionic hemorrhage accumulates at site of the separation from placenta.
• May continue to bleed after initial hemorrhage when blood tracks behind the membranes and through cervix
• This is old blood; frequently brownish in color
• Carefully scan along edge of placenta to identify a marginal abruption.
heterogeneous Placentomegaly causes
Molar pregnancy, triploidy, placental hemmorrhage
Homogeneous Placentomegaly
Gestational diabetes, anemia, hydrops, infection, aneuploidy
Intervillous Thrombus
echogenic cystic lesions, appear and grow in 3rd trimester
Placental infarcts
triangular white hyperechoic areas due to thrombis of spiral arteries
Most common cause of retained products
Succenturiate Lobe
Partial Placental Previa
Over internal os from one side
Destructive/ progressive lesions (2)
intervillous thrombus and infarcts
Infarct of >10% of placenta
IUGR, Fetal hypoxia, fetal Demise
Coiling of the umbilical cord is generally: a
. toward the left
Wharton’s jelly
Mucoid connective tissue that surrounds the vessels within the umbilical cord
Chorioangioma
The hypochoic mass compared with the normal.
placenta parenchyma is a chorioangioma (arrow). Vascularity is
demonstrated with color Doppler
The diameter of the umbilical cord has been measured to be between ___________________ and
___________________ cm; variations in cord diameter are usually attributed to diffuse accumulation of Wharton’s jelly.
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