Placenta pathology

________ _____ are functional endocrine units of placenta

chorionic villi

3 activities of the placenta

metabolism, endocrine secretion and transfer

What are the 6 functions of the placenta?

respiration, nutrition, excretion, protection, storage, hormonal production

The placenta is seen on sonography as early as

8-10 weeks

Normal sonography of the placenta

Homogenous pebble gray appearance with smooth borders

Fetal surface of placenta is ______ chorionic plate coursing along placental tissue

echogenic

The basal plate is the _____ side of the placenta

maternal

_________ is thin, hypoechoic layer posterior to basilar veins.

myometrium

Placental sonolucencies referred to as

placental lakes

Normal placenta should not exceed _cm

4cm

If maternal bladder full, cervix is falsely ________

elongated

Does the placenta migrate or change positions?

no

Grade 0: <18 weeks

uniform echogenicity, smooth chorionic plate

Grade I: 18-29 weeks

occasional parenchymal calcification/hyperechoic areas

subtle indentations of chorionic plate

Grade II: ​30-38 weeks

occasional basal calcification/hyperechoic areas

deeper indentations of the chorionic plate

Grade III: ​​≥ 39 weeks

significant basal plate calcification

chorionic plate interrupted by indentations (frequently calcified) that reach up to the basal plate:

Causes of enlarged placenta

1) Anemia

2) Diabetes

3) Hemorrhage

4) Infection

5) Uterine anomaly

Causes of small placenta

1) IUGR

2) Infection

3) Infarction

Battledore (marginal) insertion

is at or close to the placental margin within less that 2cm from the edge

Velamentous insertion

insertion into the fetal membrane and then travels to the placenta within the membrane

What is placenta previa?

Placenta over the internal cervical os

Complete placenta previa

the entire cervix is covered

Partial placenta previa

only partially covers the internal os

Marginal placenta previa

does not cover the os but the edge comes to the margin of the os

Low lying placenta previa

close to the os but not overlying it

Vasa previa

Occurs when large fetal vessels run in fetal membranes across cervical os

Placenta accreta

Abnormal adherence of part or all of the placenta with partial or complete absence of the decidual basalis. Chorionic villi attach to myometrium without muscular invasion.

Placenta increta

further extension of the placenta through the myometrium.

Placenta percreta

further extension through the uterine serosa. May extend to bladder and rectum.

Intervillous Thrombosis

Presence of thrombus within intervillous spaces occurs in one third of pregnancies.

Succenturiate Placenta

Presence of one or more accessory lobes connected to body of placenta by placental vessels

Circumvallate/Circummarginate Placenta

attachment of placental membranes to fetal surface of placenta rather than to underlying villous placental margin.

Locations of placental hemorrhage

retroplacental, subchorionic, subamniotic, and intraplacental sites

Placental Abruption

premature placental dettachment

Retroplacental Abruption

Results from rupture of spiral arteries and is “high-pressure”bleed

Retroplacental abruption is associated with ________ and _______

hypertension and vascular disease

Marginal Abruption

Hemorrhage results from tears of the marginal veins and represents “low-pressure”bleed.

Chorioangioma

Benign vascular tumor of placenta.

Most common tumor of the placenta

chorioangioma

Uterine artery sonographically reveals _____-resistance flow pattern first trimester.

high resistance

Second trimester should show _____-resistance flow pattern.

low resistance