Placental Pathology Flashcards
By 12 weeks of gestation, two distinct components of the placenta are recognizable, what are they?
- Fetal portion
- Maternal portion
What is another name for the fetal portion?
Chorion frondosum AKA chorionic plate
What is another name for the maternal portion?
Decidua basalia AKA basal plate
What is the two portions of the placenta held together by?
Anchoring stem villi at the Cytotrophoblastic shell
Projections of the decidua basalis is called what? What does it do?
- Placental septa
- Divides the placenta into compartments
What is a cotyledon?
Compartment of the placental septa
There are about ____ cotyledons in a placenta?
20
Basic texture of the placenta changes how during gestation?
Does not change with gestational age except for the deposition of calcium
Placental calcifications are present in >50% of placentas after how many weeks?
33 weeks
Calcium deposits are found primarily in what area?
Basal plate or septa, but may be seen in the subchorionic and previllous spaces
Amount of calcification is increased in patients with what three things?
- IUGR
- Hypertension
- Smoking
How many grades of the placenta are there?
4: Grade 0-3
What is a grade 0 placenta?
Homogenous, chorionic plate is straight
What does a grade 1 placenta look like?
- Scattered echogenic areas
- Subtle undulations
What does a grade 2 placenta look like? 2
- Indentations
- Linear echogenic areas
What does a grade 3 placenta look like? 3
- Indentations to basal layer
- Cystic areas
- Shadowing calcifications (after 36-38 weeks)
How do we document the placenta? What do we need to ensure during this process? 4
- Document the placental position in SAG and TRX.
- Measure from placental edge to the internal OS of the cervix
- Document the placental cord insertion in SAG and TRX
- Ensure there is only one placental mass
What do we need to assess during placental documentation?
Texture and thickness
During placental documentation we need to measure the placenta how?
From the placental edge to the internal OS of the cervix
The placenta should be a minimum of ________ away from the internal OS of the cervix?
2cm
The cord insertion for the placenta should be how far from the placental edge in both planes?
> 2cm
What is the shape of the placenta?
Flat and circular
How heavy is the placenta?
500-600 grams
How thick is the placenta?
1.5 - 4cm
The placenta grows how much a week in thickness?
1mm
When measuring the placenta, we do not include what in the measurement?
The myometrium or retroplacental complex
What is considered placentalmegaly?
> 4cm
What is the etiology of placentomegaly? 6
- Maternal diabetes
- Maternal anemia
- Hydrops
- Intrauterine infection
- Partial mole
- Chromosomal abnormalities
Thickness of the placenta usually depends on what?
Gestational age
What is considered a thin placenta?
<1.5 cm
Why do we normally have thin placenta?
Placenta insufficiency
What is the etiology of thin placenta? 2
- Vascular deficiency or infarction
- Pre-eclampsia
What are some pre-eclampsia signs that results in thin placentas? 3
- Hypertension
- Proteinuria
- Edema
Thin placenta may cause what?
IUGR
Intraplacental lesions have what type of clinical significance?
None
What are two examples of intraplacental lesions?
- Maternal lakes (Subchorionic fibrin deposition)
- Placental lakes (Perivillous fibrin deposition)
What are maternal lakes?
Sonolucent area adjacent to chorionic plate
What does maternal lakes result in?
Pooling and stasis of maternal blood
Often what type of flow is demonstrated in maternal lakes?
Rouleaux flow
What does placental lakes look like? What might be visualized with them?
Well defined intraplacental hypoechoic lesions in which rouleaux flow is sometimes visible.
What is placental lakes caused by?
Turbulence and stasis of maternal blood in intervillous space within secondary fibrin deposition
Placental lakes can be abnormal if seen in 1st trimester, why?
Due to association with placenta accreta spectrum and placental insufficiency
What are two examples of intraplacental lesions? (besides plcanetal and maternal lakes)
- Intervillous and subchorionic thrombus
- Septal cysts
What are intervillous and subchorionic thrombus caused by?
Fetal bleeding into intervillous space
What does intervillous and subchorionic thrombus contain? How do they appear?
Fibrin and appear as intraplacental hypoechic lesions
Where are intervillous and subchorionic thrombosis located?
Perivillous and subchorionic spaces
Intervillous sand subchorionic thrombus are thought to be how significant? What are they associated with?
Insignificant as well but are associated with RH isoimmunization cases
Septal cysts are located where?
Top of septa.
Septal cysts are thought to be a result from what?
Obstructed venous drainage
How does septal cysts appear?
Hypoechoic intraplacental lesions
What are placental infarcts?
Microscopic triangular shaped lesions on maternal side of placenta
What are placental infarcts due to? What does it lead to?
Obstruction of maternal blood flow leading to necrosis
In terms of placental infarcts, over 10% involvement of the placenta is considered what three things?
- Extensive and associated with IUGR
- Fetal hypoxia
- Fetal demise
Are placental infarcts generally seen on U/S?
No
Most placenta look how in the 1st and early second trimester?
Low
What can make the placenta look low?
Distended bladders
How does placenta previa appear? What are two other names for placenta previa?
- Low lying
- Marginal or partial placental previa
- Complete placenta previa
What is the clinical history for placenta previa? (S/S)
Painless vaginal bleeding
What is a low lying placenta?
When the placenta is <2cm from the internal OS but not overlying it
What is a partial placenta previa?
Placenta touches the internal OS
What is a complete placental previa?
Placenta completely covers the internal OS
What do we need to do if the bladder is over distended when viewing the placenta previa?
Empty some bladder
When would we empty the bladder when look for placenta previa? 2
- If cervix looks longer than 4 cm
- Over distended
Why do we need to empty the bladder when we assess for placenta previa?
To asses for uterine contraction in cervix area
At the 18-20 week scan, if the placenta is <2cm from the internal os after a post void bladder assessment, what must be done? How long will they need to do this?
- The patient will return at 24-28 weeks for follow up
- Until the placenta migrates away from the internal OS by >2cm. Most do migrate but a few will continue to be low lying
What do we need to use with EV for placenta previa?
Use condom or non latex probe cover
What does EV for placenta previa require from sonographers?
Experience
What is required from the patient for a EV for placenta previa? 2
- No bleeding for 24 hours
- Empty bladder
What is the process of EV for placenta previa? 2
- Insert slowly under direct visualization
- Use little to no pressure against cervix
Where does the umbilical cord attachment to placenta insert?
At or near the center of placenta
What is a battledore?
Marginal cord insertion
Where is the cord of a battledore in terms of the placental edge?
<2cm
What can a battledore progress to?
Velamentous
What is a velamentou insertion?
Cord inserting into the chorionic membranes and then vessels track to placenta
With velamentous insertion, vessels are not protected by placenta or Wharton jelly, therefore more susceptible to what?
Rupture
Battledores and velamentous CI are associated with what? (Conditions) 4
- IUGR
- FHR abnormalities
- Placental abruption
- Preterm labour
What are some variations in shape for battledore s and velamentous CI? 3
- Succenturiate
- Extrachorial
- Membranacea
What are two different branches of extrachorial?
- Circummarginate
- Circumvallate
What is a succenturiate? 2
- Accessory lobe
- Separate piece of placenta connected to main placenta via vessels within membrane
Succenturiate are at a higher risk of what two things?
- Increased risk of retained products
- Increased risk of vasa previa
What are vasa previa in relation to succenturiate?
Vessels connecting placenta to succenturiate lobe going across cervix
What is a vasa previa?
Unprotected fetal vessels travelling in the membranes across the lower uterine segment of cervix
In terms of vasa previa, vessels may do what?
Rupture in labour or with rupture of membranes, carrying a high risk of fetal death
If Vasa previa is identified penatally, what is planned? What does this do for survival rate?
C-section is planned for 34-36 weeks and outcome is >97% survival rate
What are some risk factors for vasa previa? 3
- Velamentous or marginal CI into placenta
- Resolving placenta previa
- Succenturiate lobes of placenta
What does a screening look like for vasa previa? 3
What do we look for with vasa previa during evaluation of the lower uterine segment and cervix?
Bubbles and lines when evaluating the lower uterine segment and cervix
Extrachorial placenta occurs when?
The chorionic plate does not extend to the edge of placenta. Chorionic membrane extends over placenta
What are two types of Extrachorial placenta?
- Circummarginate
- Circumvallate
What does Circummarginate looks like?
A flat ring at attachment to chorionic plate
What does a Circumvallate look like? 2
- Fold in the membrane at site of attachment
- Placenta and fetal membranes fold back towards the chronic surface
What are complications of Circumvallates? 3
- Increased risk of placental abruption
- Placental insufficiency (fetal IUGR)
- PRL hemorrhage at delivery
In both Circummarginate and Circumvallate placentas the chorionic plate does not do what?
Extend to the edge of the placenta
What is a synechiae?
Area of scarring in endometrium
Compared to the rest of the uterus, what does the synechiae not do?
Stretch
Synechiae leaves the appearance of what?
A membrane that just ends
With a synechiae, we can see what in terms of fetal parts?
Fetal parts on both sides of membrane but fetus is not attached to it as it would in an amniotic band syndrome
What are the potential complications of Circumvallate placenta? 5
- Placental rupture
- Placental insufficiency
- Hemorrhage
- IUGR
- Preterm labour
What is the biggest concern for succenturiate lobes?
Vasa previa
What is synechiae associated with?
Asherman’s syndrome
What is a placenta membranacea?
Entire uterine surface is covered with placenta
How does placenta membranacea form?
Due to failure of smooth chorion to compress and become the chorionic membrane in embryology
How common is placenta membranacea?
Very rare
What are some complications of placenta membranacea? 5
- Placenta previa
- IUGR
- Fetal demise
- Postpartum hemorrhage
- Retained tissue post delivery
What might placental hemorrhage occur with in terms of placental abruption? 2
- Marginal
- Retroplacenta
What are three different formation of placental abruption?
- External bleeding, no hematoma
- Retroplacental hematoma without external bleeding
- Subchorionic hematoma with or without bleeding
Placenta abruption may be caused by what? 6
- Abdominal trauma
- Short umbilical cord
- PIH (pregnancy induced hypertension)
- Maternal vascular disease
- Maternal smoking and/or drug usage
- Fibroids
What are symptoms of placental abruptions? 3
- Preterm labor contractions
- Bleeding
- PAIN
What is the sonographic apeparence of placenta abruptions? 2
- Sonolucent or complex mass beneath chorionic membrane
- Placental thickening, often >5.5cm
What are three examples of tumors in the placenta?
- Teratoma
- Chorioangioma
- Metastatic tumors
What is a teratoma in a placenta?
A rare germ cell tumor
What is a chorioangioma?
Vascular tumor, usually single
What does a chorioangioma look like? 2
- Well defined solid/complex mass
- If large, may cause hydrops and heart failure
How might metastatic tumors arrive in the placenta?
Metastatic tumours may spread to the placenta from mother or fetus, though rare
What does PAS stand for?
Placenta Accreta Spectrum
What is PAS?
When the placenta does not attach properly to the basalis but rather invades into and beyond the maternal basalis layer
What are three types of PAS?
- Accreta
- Increta
- Precreta
What happens with PAS Accreta?
Attaches to myometrim
What does PAS Increta look like?
Invades into myometrium
What does a PAS Precreta look like?
Invades through the myometrium to perimetrium and even beyond
What are some risks of placenta Increta a or Precreta risks? 2
- Increased risk of having acreta after C section or other uterine surgery
- Increased risk of bleeding postpartum, because the placenta has invaded into the uterine wall it is difficult to remove at delivery
Placenta Increta or Precreta may result in what at delivery?
Hysterectomy at delivery
What are some common risks of accreta? 2
- Placenta previa (anterior placenta)
- Prior c-section
What can accreta be associated with? 7
- Advanced maternal age
- Increased parity
- Uterine abnormalities
- Smoking
- Myomectomy
- Previous uterine surgery
- Previous D and C
In terms of placenta Increta or Precreta, what is great question to ask if a patient is Graviida 2 or more?
have you had a C-section delivery
What are some sonographic appearance or signs with accreta? 5
- Anterior placenta
- Presence of numerous lacunae
- Look for a “clear zone” between placenta wall in the retroplacental area
- Thin or imperceptible myometrium
- Bladder line loss
In terms of accreta, what are some things we need to look for with anterior placenta? 2
- Low lying or anterior previa
- Previous c-section deliveries
In terms of accreta, when we look for a “Clear zone” between placenta and uterine wall in the retroplacental area, what area some things we might see? 2 (abnormal and normal)
- Abnormal if this clear zone cannot be demonstrated
- Normal placental clear zone, applying pressure to the clear zone will disappear
In terms of accreta, what constitute bladder line loss? 3
- Not as sharp or clear
- Lumpy or bumpy
- Bulges into the bladder
What is diagnosis like for accreta on u/s? What can be seen?
- Difficult on U/S
- Only Anterior placenta
What should we look for in terms of a diagnosis of accreta? What can help us look? 3
- Absent or severely thinned myometrium
- Extension to adjacent organs
- Use colour doppler
What can be used to diagnose accreta in the case of ambiguous ultrasound findings?
MRI
What does the umbilical cord develop from?
Connecting stock and yolk sac
What is the vessel information in the umbilical cord?
2 arteries and 1 vein
What is the umbilical cord vessels surrounded by?
Whartons jelly
What is umbilical cords covered with?
Amnions
How long is Umbilical Cord?
50-100cm long
What is cord cysts remnants of?
Allantoic remnant
How significant is cord cysts?
Transient and insignificant
Multiple cord cysts can be associated with what? 3
- T18
- T13
- Increased risk of miscarriage
What are two types of cord knots?
True or false knots
False chord knots are due to what?
Cord kink or redundancy
How Common are true knots?
Rare (<1% of pregnancy)
Most true knots are what? (what happens to them)
Lost
What are risk factors of Cord knots? 3 (what causes it)
- Long cord
- Polyhydraminos
- Excessive fetal movements
What is a highly specific sign for true or false cord knots?
Hanging noose sign
What modality can be used for further characterization of cord knots?
3D/4D
What is a umbilical vein varix?
Intra-abdominal focal enlargement of the umbilical vein
What might happen in umbilical vein varix?
Stasis may occur here and blood may clot
What is umbilical vein varix associated with?
A higher incidence of adverse outcomes
Label
Label
Label the image
What does this image represent?
The placental appearance on u/s
What does this image represent?
Grade 3 placenta
What does these images represent?
SAG placenta and TRX placenta
What does this image represent?
Placenta measurements: The placental edge to the internal OS of the cervix
What does these images represent?
Placental documentation of the cord insertion
What does this image represent?
Size and shape of the placenta in trans
What does this image represent? (think size)
Placentomegaly
What does this image represent?
- Maternal lakes
- Placental Lakes
What does this image represent?
Placental Lakes
What does this image represent?
Maternal lake
What does this image represent?
Placental position with a distended bladder and the low lying placental bladder
What does these images represent?
Placental Previa
A. Low lying <2cm from internal os
B. Marginal Previa
C. Partial Previa
D. Complete previa
What does this image represent?
Low lying placenta - when the placenta is <2cm from the interlay OS but not overlying it
What does this image represent?
Partial placental previa
What does this image represent?
Complete placenta previa
Label
What does this image represent?
Low lying placenta
What does this image represent?
Normal Transabdominal cervix at 18 weeks LMP
What does this image represent?
Normal Endovaginal cervix at 18 weeks
What does these images represent?
- Cord insertion into placenta
- Inserts at or near center of placenta
What does these two images represent?
- Marginal CI (Battledore)
- Velamentous CI
What does these images represent?
Marginal CI and Velamentous CI
What does this image represent?
Succenturiate
What does these images represent?
Succenturiate placenta
What does these images represent?
- “Bubbles and Line” when evaluating the lower uterine segment and cervix for vasa previa
- Bubbles on the top row and lines on the second row
What does this image represent?
Vasa previa arterial waveform, which matches fetal heart rate
What does these images represent?
Vasa previa vs funic presentation
What does these images represent?
- Normal
- Circummarginate
- Circumvallate
What does these images represent?
A. Circummarginate
B. Circumvallate
What does these images represent?
Circumvallate
What does this image represent?
Circumvallate
What does this image represent?
Circumvallate
What does this image represent?
Synechiae
What does this image represent?
Synechiae
What does this image represent?
Synechiae
What does this image represent?
Synechiae
What does this image represent?
Placenta membranacea
What does these images represent?
Placenta abruption
A. External bleeding, no hematoma
B. Retroplacental hematoma without external bleeding
C. Subchorionic hematoma with or without bleeding
What does this image represent?
Sonographic appearence of abruptions
What does this image represent?
Amniotic hematoma
What does this image represent?
Chorioangioma
Label
- Normal creta
- Accreta
- Increta
- Percreta
Label
What does this image represent?
Clear zone
What does this image represent?
Clear zone disappears with probe pressure
1. Clear zone is hypoechoic
2. Slight pressure the clear zone disappears. Normal placental bed
What does this image represent?
Loss of clear zone due to invasive placenta
What does this image represent?
Label
What does this image represent?
Umbilical cord
What does this image represent?
2UA = 3 vessel cord
What does this image represent?
Cord cyst
What does this image represent?
Cord knots
What does this image represent?
Umbilical vein varix
What does this image represent?
Umbilical cord varix
What is this?
Hanging noose sign for a cord knot
What is a fecalith?
A 30 year old male whose sub type is Brian
- Cheats on bench
- Probably is a caffeine addiction
- is a weaker sub type of the chuong variation