Placenta and Umbilical Cord Flashcards
(33 cards)
Basal plate vs chorionic plate?
Basal plate - maternal surface of placenta
Chorionic plate - fetal surface of placenta
Circumvallate placenta
Chorionic plate is smaller than the basal place of the placenta
Placenta accreta
Growth of chorionic villi penetrate the decidua but do not invade the myometrium - this is an abnormal placenta attachment to the myometrium that DOES NOT separate after delivery
(grows a tiny bit into uterine wall) - least invasive
Numerous placental lakes
Placenta increta
Growth of the chorionic villi deep into the myometrium
(grows into the uterine muscle)
Placenta percreta
Growth of the chorionic villi through the myometrium and serosa
(goes all the way through the uterine wall/muscle, and sometimes invades other organs)
What cells does the placenta develop from?
Trophoblastic cells that make up the chorion
What are the functions of the placenta?
Respiration, nutrition, excretion, protection, storage, hormone production
What can cause premature maturation of the placenta?
Maternal hypertension, cigarettes, IUGR, and multigestaton
Delayed maturation of associated with which maternal condition?
Maternal diabetes mellitus
What grade of placenta is m/c up to 34 wks?
Stage 1
Grade 3 placentas typically appear in which week of GA?
34 wks and after
What is the primary cause of painless bleeding in 3rd trimester?
Placenta previa
What is a low-lying placenta?
A placenta within 2cm of the internal os, but does not cover the os
What is vasa previa?
When fetal vessels cross over the internal os
How large does the placenta measure in both second and third trimester?
Typically 2-3 cm in greatest thickness
Maximum thickness SHOULD NOT be above 4.0cm in SECOND trimester
6.0cm in THIRD trimester
Circumvallate placenta
Appears as irregular edges, uplifted margins, or placental sheets - can increase risk for abruption, IUGR, premature labor, and bleeding
Will show as a ‘rolled up’ edge, thick placental cord insertion
What is the appearance of a placental infarct?
Hypoechoic focal placental mass, calcification may occur - may be mistaken for placental lake
Occurs in a 1/4 of pregnancies, no clinical risk when SMALL
Placental lakes are insignificant unless they are found at which trimester of the pregnancy?
1st trimester
Placentomalacia
Small placenta, less than 1.5cm AP, associated w/:
- eccentric cord insertion
- IUGR
- intrauterine infection
- chromosomal abnormality
- maternal diabetes
What is placentomegaly associated with? What is its size?
- maternal anemia
- fetal hydrops
- TTTS
- fetal anomalies
- uterine infection
> 4.0cm before 24 weeks
6.0cm in third trimester
Heterogenous placentomegaly is associated with which conditions?
Triploidy
Molar Pregnancy
Hemorrhage
het - HMT
Homogenous placentomegaly is associated with which conditions?
Anemia, hydrops, and Rh sensitivity
homo- HAR
If additional placenta tissue is seen adjacent to the main placenta, connected by blood vessels, what is this suggestive of?
Succenturiate placenta
What is the most common benign tumor of the placenta?
Chorioangioma
