Placenta Flashcards by Allison Zarnke

Which hormone is secreted by the placenta?

hCG (+ many others)

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What is the decidua?

Endometrium of pregnancy

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Are the chorion/amnion derived from maternal or fetal tissue?

Fetal tissue

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What is the function of the chorionic villi?

Chorionic villi sprout from the chorion to provide a large contact area between fetal and maternal circulations

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What is the two layered epithelium of the chorion called?

Trophoblast

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Do the fetal and maternal blood sources mix?

NO- not under normal circumstances

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Does the umbilical vein bring oxygenated or deoxygenated blood to the fetus?

oxygenated

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How does fetal blood become oxygenated?

The placenta is like the lungs for the fetal blood- the oxygenated maternal blood enters in spiral/endometrial arteries and bathes the fetal blood supply- oxygen is extracted

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Spontaneous abortions (miscarriages) occur when?

Anytime before 20 weeks

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What is the primary cause of a spontaneous abortion?

More than half are due to chromosomal abnormalities

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Where do ectopic pregnancies usually occur?

90% occur in the fallopian tubes

10% occur in the ovary or abdominal cavity

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Name 2 predisposing factors to ectopic pregnancies

Previous inflammation that led to scarring

IUDs

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How will an ectopic pregnancy present?

Abdominal pain, acute abdomen

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Will a monochorionic placenta produce fraternal or identical twins?

Identical

Monochorionic placentas imply monozygotic twins

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What is the cause of twin-twin transfusion syndrome?

Intertwin vascular connections within the placenta

Leads to polyhydramnios in one amniotic sac, and oligohydramnios in the other amniotic sac

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What is it called when the placenta attaches to the lower uterine segment or cervix?

Placenta previa

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What are the consequences of placenta previa?

Serious 3rd trimester bleeding

Dilation of the cervix disrupts the placenta

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What is it called when there is partial or complete absence of the decidua with adherence of placental villous tissue directly to the myometrium?

Placenta accreta

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What are the consequences of placenta accreta?

Failure of placental separation –> incomplete/non-delivery of the placenta following birth.

Causes postpartum bleeding

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Name 2 predisposing factors to placenta accreta

Placenta previa (60%)
Previous cesarean section

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What is it called when there is a premature separation of the placenta and formation of a retroplacental blood clot?

Abruptio placentae

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What are the consequences of abruptio placentae?

Painful maternal bleeding

Potential fetal death due to inadequate blood supply to the fetus

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What are consequences of retained placental tissue?

Postpartum hemorrhage

Infection

What is Preeclampsia-eclampsia?

Systemic syndrome characterized by widespread maternal endothelial dysfunction presenting clinically with hypertension, edema and proteinuria during pregnancy

Is preeclampsia more common with the first pregnancy or subsequent pregnancies?

First preganancy

What causes preeclampsia-eclampsia?

Not sure, but delivery of the placenta rapidly reverses the symptoms (Coagulation abnormalities? Endothelial dysfunction and imbalance? Abnormal placental vasculature?)

How is the liver affected by preeclampsia?

Fibrin thrombi, hemorrhage, necrosis

How are the kidneys affected by preeclampsia?

Fibrin in glomeruli and capillaries | Renal cortical necrosis

How is the brain affected by preeclampsia?

hemorrhage and thrombosis

What is the triad at defines preeclampsia?

HTN, edema, proteinuria

What defines severe preeclampsia?

Preeclampsia + headaches and vision changes

What defines eclampsia?

Preeclampsia + convulsions

What is HELLP syndrome

Severe preeclampsia + hemolysis, elevated liver enzymes, and low platelets

What are some long term maternal sequelae of preeclampsia?

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

What is the most common route of a placental infection?

Ascending- usually bacterial, through the birth canal | Less commonly, TORCH infection through hematogenous spread

List the TORCH infections

``` T- Toxoplasma Gondii O-Others (Parvovirus B 19), Syphilis, TB, listeria R- Rubella C- CMV H- Herpes simplex virus, HIV ```

What are the symptoms of a TORCH infection?

fever, encephalitis, chorioretinitis, hepatosplenomegaly, pneumonitis, myocarditis, hemolytic anemia and vesicular or hemorrhagic skin lesions

Generally speaking, what are hydatidiform moles?

A noncancerous tumor that develops in the uterus as a result of a nonviable pregnancy Leads to cystic swelling of the chorionic villi with trophoblastic proliferation

What is the general presentation of a hydatidiform mole?

Most women present with miscarriage, and undergo D&C based on the US/hCG findings

In complete hydatidiform moles, how many chromosomes are present? What is their origin?

46 chromosomes are present, BOTH sets are from the male origin.

What are the two ways a complete hydatidiform mole can arise?

Empty ovum penetrated by two sperm --> 46 chromosomes Empty ovum penetrated by one sperm which duplicates such that there are now 46 chromosomes

What is the origin of the chromosomes of a partial hydatidiform mole?

Two sperms enter an ovum with 23 chromosomes already --> 69 chromosomes

What is the karyotype of partial vs complete hydatidiform moles?

Complete: 46, XX or 46, XY Partial: Triploid

Describe the presence of villous edema in partial vs complete moles

Complete: all villi are edematous Partial: some villi are edematous

Describe the trophoblast proliferation of partial vs complete moles

Complete: Diffuse, circumferential Partial: Focal, slight

Describe the histologic atypia of complete vs partial moles

Complete; often present | Partial: absent

Describe the serum hCG levels in complete vs partial moles

Complete: Elevated Partial: less elevated

Is fetal tissue present in complete moles? Partial moles?

Complete; Fetal tissue is absent | Partial: Fetal tissue is present

Describe the malignant potential of complete vs partial moles

Complete; 2.5% progress to choriocarcinomas (often fatal) | Partial: almost zero malignant potential

What defines an invasive mole?

A mole that penetrates the uterine wall- villi invade the myometrium

How are invasive hydatidiform moles treated?

Chemotherapy

Are gestational choriocarcinomas malignant or benign?

Malignant- they are rapidly invasive and widely metastatic

Gestational choriocarcinomas are neoplasms arising from which cell type?

Trophoblast derived cells

What is the treatment for choriorcarcinoma?

Surgery and chemotherapy- chemo is extremely effective

What does the chorion attach to?

The decidua

Do ovarian choriocarcinomas require fertilization?

No- they are non-gestational, and a result of extra-embryonic differentiation in malignant germ cells

What is the prognosis for ovarian choriocarcinomas?

Poor response to chemotherapy, poor prognosis