Module 16 : Placenta Pathology Flashcards by Adyson Strong

what are the grades of the placenta

0, I, II, III

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what is a grade 0 placenta

homogeneous
chorionic plate is straight
< 18 weeks

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what is a grade I placenta

scattered echogenic areas
subtle undulations
18-22 weeks

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what is a grade II placenta

indentations
linear echogenic area
22-36 weeks

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what is a grade III placenta

indentations to basal layer
cystic areas
shadowing calcs
> 36 weeks

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what measurement is considered placentomegaly

> 4cm thick

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what was the aetiology of placentomegaly

maternal diabetes
maternal anemia
hydrops
placental hemorrhage
intrauterine infection
partial mole
chromosomal abnormalities

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what does the thickness of the placenta depend on

gestational age

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what does a thin placenta usually result in

placental insufficiency

- may cause IUGR

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what are the 2 etiologys of thin placenta

vascular deficiencies or infarct

- pre eclampsia - toxaemia of late pregnancy

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do intraplacental lesions have any clinical significance

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what is a maternal lake

subchorionic fibrin deposition

- right along placental edge on baby side

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what is a placental lake

perivilus fibrin deposit

- on maternal side

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what are the 4 intraplacental lesions

maternal lake
placental lake
intervillous thrombosis
septal cysts

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what are the characteristics of placental infarcts

microscopic triangular shaped lesions on maternal side of placenta
due to obstruction of maternal blood flow
> 10% extensive
not seen with ultrasound

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where do most placenta look like they are in the 1st and early second trimester

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what other factor can make the placenta look like

bladder distended

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what are the characteristics of placental previa

low lying

- marginal or partial or complete

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what is the clinical history of placenta previa

painless vaginal bleeding

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what are the characteristics of low lying placenta

< 2cm from internal os but not overlaying it

what is partial placenta previa

placenta touches the internal os

what is complete placenta previa

placenta completely covers the internal os

what are some factors to take into account when assessing for placenta previa

empty bladder some if fully distended
if cervix looks longer than 4cm empty bladder
assess for uterine contraction cervix area

is the placenta is < 2cm away from internal os at 18 weeks scan what is done

if still same after post void
patient returns in a few weeks
EV of the cervix with color doppler is performed at 24-28 weeks (look for vaso previa)
patient will continue to return every 2 weeks until placenta moves away

protocol for EV with placenta previa

- use condom or on latex probe cover - experience - no bleeding for 24 hours - insert under visualization - no or ver little pressure against cervix

what are the 3 types of placental shape

- succenturiate - extrachorial - membranacea

characteristics of succentruriate placenta -

- accessory lobe - separate piece of placenta connected to main placenta via vessels within membrane - increased risk of retained products - could have vasoprevia

characteristics of extrachorial placenta

- chorionic plate does not extend to edge of placenta - chorionic membrane extends over placenta - circummarginate - circumvallate - may cause antepartum hemorrhage

what is a circummarginate placenta

- a flat ring at attachment to chorionic plate

what is a circumvallate placenta

- fold in membrane at site of attachment

what is a synechie (amniotic sheet) placenta

- are of scarring in endo does not stretch like rest of uterus - leave appearance of membrane that just ends - can see fetal parts on both side of membrane but fetus not attached to it

characteristics of placenta membranacea

- entire uterine surface is covered with placenta | - failure of smooth chorion to compress and become chorionic membrane in embryology

what are the 2 variations in cord insertion

- battledore | - velamentous insertion

what is a battledore cord insertion

- marginal cord insertion | - cord < 2cm from placental edge

what is a velamentous insertion

- cord inserting into the chorionic membrane and then vessels track to placenta

what is vasa previa

- fetal vessels across internal os

what are the 2 common locations of placental hemorrhage

- marginal | - retroplacental

what're the 3 different formations of placental abruption

- external bleeding no hematoma - retroplacental hematoma whiteout external bleeding - subchorionic hematoma with or without bleeding

what may cause a placental abruption

- trauma - short umbilical cord - PIH - maternal vascular disease - maternal smoking and or drug usage - fibroids

what are the symptoms of placental abruptions

- preterm labor contractions - bleeding - pain - fetal distress

what is the sonographic appearance of placental abruption

- sonolucent or complex mass beneath placenta or beneath chorionic membrane

what are the 2 tumors of the placenta

- teratoma = rare germ cell tumor - chorioangioma = vascular well defined complex mass - mets

what is is placenta Creta and what are the 3 types

- when the placenta does not attach properly to basalts but rather invades beyond the basalis - accreta - increta - percreta

what is accreta

- attaches to myometrium

what is increta

- invades myometrium

what is percreta

- invades through perimetrium and even beyond

what are some characteristics of placenta accreta

- increase risk of bleeding post part - increase risk after c section because of scar - may result in hysterectomy - extremely dangerous for mother

what is the diagnosis of acreta

- very difficult on ultrasound - only anterior placentas - absent or severely thinned myometrium - extension to adjacent organs - color doppler

what are the common risks with placenta accreta

- placenta previa | - prior c section