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Flashcards in Placenta Deck (30):
1

The placenta is composed of two layers the amnion (inner layer) and the chorion the outer layer, what does the chorion attach to?

decidua=endometrium of pregnancy

2

What is the chorionic villi?

placenta composed of chorionic villi that sprout from the chorion to provide large contact area between fetal and maternal circulation
_BLOOD DOES NOT MIX

1. central stroma
2. epithelium
-syncytiotrophoblast
-cytotrophoblast

-3rd trimester villi are smaller and vasculature more pronounced and see fibrosis

3

Spontaneous abortion

lost before 20 weeks
1/3 of all pregnancies lost
-more than half due to chromosomal abnormalities
-defective implantation
-fetal abnormalities
-maternal causes (inflammation, uterine deformity, DM, luteal-phase defects)
-unkown

4

Ectopic Pregnancy

Implantation occurs outside uterus
1:150 pregnancies
90% fallopian tubes
10% ovary and abdominal cavity

Predisposing factors
-inflammation and scarring
-intrauterine device

Presentation-abdominal pain, acute abdomen

Clinical complications: rupture and hemorrhage; high mortality unless removed surgically

5

Dizygotic

fertilization of 2 ova

6

Monozygotic

division of one fertilized ovum

7

Monochorionic placenta implies what? What is the number of amnions determined by?

monozygotic (identical twins)
-time of the splitting of the ovum
monochorionic diamniotic vs monochorionic mononamnionic

8

Placenta previa

attachment of placenta to lower uterine segment of cervix
-serious 3rd trimester bleeding-dilation of cervix disrupts placenta

9

Placenta accreta

-partial or complete absence of decidua with adherence of decidua with adherence of placental villous tissue directly to myometrium -failure of placental separation

-cause of postpartum bleeding

Predisposing factors:
-placenta previa (60%)
-previous cesarean section

10

abruptio placentae

premature separation of placenta prior to delivery

formation of retroplacental blood clot
-blood supply of oxygen and nutrients to fetus compromised to greater degree with increasing size of abruption
-painful maternal bleeding
-potential fetal death

11

What happens if the placent tissue is retained postpartum?

postpartum hemorrhage
-potential infection

12

preeclampsia-eclampsia

systemic syndrome characterized by widespread maternal endothelial dysfunction presenting clinically during pregnancy with:
hypertension
edema
proteinuria

-most common with 1st pregnancies
-usually last trimester

13

What is the pathogenesis of preeclampsia-eclampsia?

placenta plays a key role
-symptoms rapidly disappear after delivery of placent

Principle theories
1. abnormal placenta vasculature
-failure of uterine spinal artery to remodel-maternal vascular hypoperfusion-placental ischemia-generalized endothelial cell injury (cytotrophoblasts allow for arteries to remodel)
2. endothelial dysfunction and imbalance of angiogenic and anti-angiogenic factors
3. coagulation abnormalities

14

What generalized processes also happen in preeclampsia-eclampsia? what happens to the placenta?

Generalized
liver: fibrin thrombi, hemorrhage, necrosis
kidney: fibrin in glomeruli and capillaries, renal cortical necrosis
brain: hemorrhage and thrombosis
heart and anterior pituitary

Placenta
Malperfusion, ischemia, vascular injury
-infarcts
-retroplacental hematoma
-villous ischemia
-acute atherosis of uterine vessels ***-fibrinoid necrosis, macrophages, inflammation

15

Preeclampsia

HTN, edema, proteinuria

16

severe preeclampsia

preeclampsia + headaches and vision changes

17

eclampsia

preeclampsia + convulsions

18

HEELP syndrome

severe preeclampsia + hemolysis, elevated liver enzymes, low platelets

19

WHat is the managment? Are there maternal sequelae after the birth?

Term=delivery
Preterm
-Mild-expectant management
-Severe-deliver regardless of fetal age


20% develop HTN and microalbuminuria within 7 years
-2X increased heart and brain vascular disease

20

Placental infections
2 pathways

1. ascending
-through birth canal
-usually bacterial
-result=premature rupture of membranes, pre-term delivery

2. Hematogenous
-transplacental
-TORCH

21

What do you see in acute chorioamnionitis?

green purulent membranes
PMNS

22

TORCH infections

T-toxoplasma gondii
O-others: parvovirus B 19, Syphilis, TB, listeria
R-rubella
C-CMV
H-Herpes simplex virus, HIV

-all may evoke:
1. fever
2. encephalitis
3. chorioretinitis
4. hepatosplenomegaly
5. pneumonitis
6. myocarditis
7. hemolytic anemia
8. vesicular or hemorrhagic skin lesions

23

Hydatidiform Moles

cystic swelling of chorionic villi with trophoblastic proliferation
-infrequent
-women present with miscarriage and undergo D&C based on US/HCG findings
-BENIGN-we want to know and distinguish them with regard to invasive mole or choriocarcinoma

24

What chromosomes make up complete and partial moles?

Complete Mole 90%
-both chromosomes are of male origin
-homozygous complete mole
-46XX

Complete Mole 10%
-both chromosomes are of male origin
-heterozygous complete mole
-46XX and 46XY

Partial Mole MOST COMMON
Sperm and ovum
-69XXX, 69XXY, 69XYY

25

Complete Mole
General
Gross
Microscopic
Clinical course

Most villi enlarged, edematous
Diffuse trophoblast hyperplasia
Androgenic (empty ovum)
Embryo dies very early (fetal parts rarely seen)
2.5% risk of choriocarcinoma

Gross:
Delicate friable mass of thin walled, translucent, cystic friable, grape like structures

Microscopic
-swollen villi with almost no fetal blood vessels
-diffuse cytotrophoblast and syncytial trophoblast proliferation
-marked atypia at implantation site

Clinical course
Abnormal uterine bleeding
passage of fluid and tissue
ultrasound diagnostic (snow storm)
-serum HCG increase
-roved via curettage; serum HCG levels monitored
-10% develop into invasive moles
-2.5 risk choriocarcinoma

26

Partial Mole
General

Some villi are edematous
Minimal Trophoblastic proliferation
One egg, two/three sperm
Fetus, although abnormal, mostly present
Not increased risk for choriocarcinoma

27

Complete mole vs Partial mole
Karyotype
Villous edema
Trophoblast proliferation
Atypia
Serum HCG
Fetal TIssue
Behavior

Complete
Karyotype: 46 XX or 46XY
Villous edema: all villi
Trophoblast proliferation: diffuse, circumfrential
Atypia: often present
Serum HCG: elevated
Fetal TIssue: absent
Behavior: 2.5% choriocarcinoma

Partial
Karyotype: triploid
Villous edema: some villi
Trophoblast proliferation: focal; slight
Atypia: absent
Serum HCG: less elevated
Fetal TIssue: present
Behavior: rare

28

Invasive Mole

Mole that penetrates uterine wall

Hydropic chorionic villi invade myometrium
-may embolize to distant sites

Clinical
vaginal bleeding
persistently elevated HCG
risk of uterine rupture

Treatment
chemotherapy

29

Gestational Choriocarcinoma

Malignant
-rapidly invasive, widely metastatic
-rapidly growing
-necrotic
-hemorrhagic

Neoplasm of trophoblast derived cells
-proliferation neoplastic cytotrophoblasts and syncytiotrophoblast
-NO CHORIONIC VILLI

Uncommon 1:20,000-30,000 Us preg

50% from complete moles
25% from previous abortions
22% normal pregnancy (intraplacental choriocarcinoma)
Ectopic pregnancy

30

How does Gestational Choriocarcinoma present? What is the treatment?

Presents as vaginal blood, brown fluid spotting
-during pregnancy, after miscarriage, after curettage
-can be months delay

Metastases usually at time of any signs

HCG elevations
-unless very necrotic

Chemo EXTREMELY effective
-paternal antigens evoke immune response in mother