Flashcards in OB Ch 55-57 Deck (74)
What are the fetal membranes comprised off
The fetal surface of the placenta
The maternal surface of the placenta
Forms the fetal part of the placenta and contains the villi
The nonvillious part of the chorion around the gestational sac
Decidua reaction that occurs between the blastocyst and the myometrium
Decidua reaction that occurs over the blastocyst closest to the endometrial cavity
Decidua vera (parietalis)
Decidua reaction except for the areas beneath and above the implanted ovum
Functions of the placenta
What is the major functioning unit of the placenta?
Refers to the insertion of the umbilical cord that inserts on the membranes
Refers to the insertion of the umbilical cord at the margin of the placenta, within 10 mm of the edge
Labor may cause the cord to prolapse or be compressed during contractions
Weeks that the chorion and amnion fuse together
How big is the yolk sac
Function of hCG
-Causes the uterine endometrium to convert to decidua, a glycogen rich mucosa that nourishes the early pregnancy
-Keeps the corpus luteum functioning, so that the corpus luteum continues to produce estrogen and progesterone
Primary cause of placentomegaly
Maternal diabetes and Rh incompatibility
Common site of fibrin deposits
Appears as hypo echoic areas beneath the chorionic plate of the placenta
Complications of previa
-Increased risk of placental invasion
-Increased risk of postpartum hemorrhage
Three placental invasions
*Penetrates beyond the endometrial lining of the uterus
Penetration of the chorionic villi through(per-) the uterus
Further extension of the chorionic villi into (in-) the myometrium
The chorionic villi attach to the myometrium without muscular invasion.
-Occurs in 1 to 2500 deliveries
Attachment of the placenta membranes to the fetal surface of the placenta rather than to the underlying villous placental margin
-Occurs in 1-2% of pregnancies
The presence of one or more accessory lobes connected to the body of the placenta-by-placenta vessels.
-Occurs in 3-6% of pregnancies
-Lobes develop infarcts and necrosis
Refers to the separation of a normally implanted placenta prior to term delivery
-Occurs in 1 in 120 pregnancies
-Bleeding into the decidua basalis
Types of abruption
Results from the rupture of spiral arteries and is a "high pressure" bleed. Associated with hypertension and vascular disease.
-Hematoma is between the placenta and uterus
Most common type; also known as subchorionic bleeds.
Results from tears of the marginal veins and represents a "low pressure" bleed.
Hemorrhage arises from the edge of the placenta, dissects beneath the placental membranes
Associated with little placental detachment
Does not cover the os, but its edge comes to the margin of the os