The Placenta Flashcards
the maternal placenta is the ___ plate
basal
flow within the maternal placenta should be ___
low resistance
___: functional unit of the placenta
cotyledons
blood fills interbillouns spaces to provide nourishment to the fetus through ____
chorionic villi
the fetal side of the placenta is the ___ plate
chorionic
the chorionic plate is located between where
between the amniotic membrane and the decidua basalis
at 12 weeks what is a normal placental thickness measurement
1.5-2cm
in the 2nd and 3rd trimester what is a normal placental thickness measurement
<4cm
the thickness of the placenta in mm should be equal to the weeks of gestation + ___
10
___: hypoechoic area deep tot hat placental that drains the placental tissue
retroplacental complex
placental insufficiency is associated with what things
-IUGR
-Pre eclampsia
-smoking
-HTN
poor maternal nutrition
-chronic maternal diabetes prior to pregnancy
-downs
-triploidy
an increasing ___ can indicate developing placental insufficiency
increasing S/D ratio
placental thinning is defined as placental thickness of ___
<1.5cm
placental thinning is associated with what things
- IUGR
- pre eclampsia
- smoking
- maternal HTN
- poor maternal nutrition
- drug/ alcohol abuse
placental thickness is defined as placenta measuring ___ in the second trimester and ___ in the third
> 4cm in 2nd trimester and >6cm in 3rd trimester
what are some things associated with placental thickening
- twin gestations
- chronic maternal diabetes
- rh incompatibility
- intrauterine infection
- triploidy
- placental insufficiency
- fetal hydrops
- beckwith Wiedemann syndrome
___: ectopic pieces of placenta not connected to the main placenta
succenturiate placental lobe
S/A grade 0 placenta
- homogeneous
- no calcs
- amniochorionic plate is even throughout
S/A grade 1 placenta
- placental body shows few echogenic densities ranging from 2-4mm
- chorionic plate shows small indentations
S/A grade 2 placenta
- chorionic plate shows marked indentations
- echogenic densities within the placenta increase in side and number
S/A grade 3 placenta
- complete indentations of chorionic plate through basilar plate
- numerous calcs
___: membranous chorion does not extend to the edge of the placenta
extrachorial placenta
___: more central attachment of the membranes without a central ring of folded amnion and chorion
circummarginate placenta
___: smaller chorionic ring surrounded by folds of thickened amnion and chorion
circumvallate placenta
circumvallate placenta has an increased risk of what
abruption or spontaneous abortion
___: pooling of maternal blood in the subchorionic space
fibrin deposition
___: ischemia of placental villi
placental infarcts
what can cause placental infarcts
obstructed maternal blood flow into intervillous space
S/A placental infarct
- triangular shaped
- anechoic with base of triangle touching the maternal side of the placenta
- does not demonstrate internal blood flow on color
___: enlarged spaces in the placenta filled with blood
placental lakes
S/A placental lake
- nearly anechoic
- slow swirling of blood may be seen
multiple placental lakes seen early on in the pregnancy has been associated with what
decreased umbilical artery flow and IUGR
___: large thrombus within the subchorionic venous system due to obstructed venous flow
breus mole
___: placental crosses the internal os of the birth canal
placental previa
what are some risk factors for placenta previa
- AMA
- smoking
- multiple gestations
- prior uterine surgery
what is the most common symptom of placental prevue
painless 3rd trimester bleeding
what are the different types of previas
- complete
- partial
- marginal
- low lying
- vasa previa
which type of previa completely covers the internal os
complete previa
which type of previa partially covers the os
partial
which type of previa touches the edge of the os
marginal
which type of previa is within 2cm of the os
low lying
which type of previa does the placental vessels cover the os
vasa
___: abnormal implantation of placental tissue
morbidly adherent placenta
who is at risk for morbidly adherent placenta
- history of grand multiparty
- history of placental previa
- prior c section
which type of abnormal placental tissue implantation invades less than 50% of the way through the myometrium
placental accrete
which type of abnormal placental tissue implantation invades more than 50% of the way through the myometrium
placental increta
which type of abnormal placental tissue implantation extends through the uterine wall to the bladder and adjacent pelvic structures
placental percreta
___: early separation of placental from the uterine wall
placental abruption
what are some risk factors for placental abruption
- short umbilical cord
- DM
- HTN
- SMoking
- pre eclampsia
- IVC compression
- AMA
- fibroids
- multiparity
S/S placental abruption
- severe bleeding
- pain
- uterine spasms
- signs of shock
S/A placental abruption
-hematomas/ fluid collections seen in retroplacental space
what is the most common benign mass of the placenta
chorioangioma
what labs would be elevated with chorioangiomyoma
MSAFP
S/A chorioangioma
- highly vascular
- hypoechoic mass
- usually adjacent to cord insertion
marginal cord insertion is also called ____
battledore placenta
which type of cord insertion attaches to the placental periphery <2cm from the edge
marginal
which type of cord insertion does the cord attach to the placental membranes
velamentous
which type of cord insertion can be seen with vasa previa
velamentous
velamentous cord insertion can lead to what
- abruption
- fetal death is PROM
velementous cord insertion is associated with what
- IUGR
- preterm birth
- congenital defects
what is the most common umbilical cord anomaly
2 vessel cord
placental previa is more commonly caused by what
low implantation of the embryo
