1st Practice Round Flashcards
Where is Alpha-fetoprotein produced?
The fetal liver and GI tract, which is excreted into the amniotic fluid.
How is MSAFP measured? (Maternal Serum Alpha-Fetoprotein)
Through bloodwork, as baby creates AFP, is is excreted into the amniotic fluid. By diffusion across the placenta, it makes it way into the maternal blood stream.
Up to 10wks gestational age, how much should the mean diameter of the normal gestational sac grow?
About 1.0mm per day
When are epiphyseal (ossification) centers identified in utero?
30wks
At how many weeks should the gestational sac fill half of the endometrial canal?
8 wks
What is a battledore placenta?
Marginal insertion - umbilical cord inserts at the edge of the placenta
When does Pregnancy-induced hypertension occur?
Second trimester
When pre-eclampsia occurs in the first trimester of pregnancy, what is it most likely indicative of?
Molar pregnancy
What sets pre-eclampsia apart from pregnancy-induced hypertension?
Pre-eclampsia is when there are additional clinical findings of proteinuria, excessive maternal weight gain, and generalized edema.
A placenta that has two equally sized lobes connected by a vessel is called?
Bipartite placenta - both lobes should be roughly equal in size
What are the sonographic criteria for identifying placenta accreta?
-loss of normal hypoechoic retroplacental myometrial zone, should measure 1-2cm, but placenta accreta is absent or significantly thinned to 2mm or less
- loss of normal venous doppler flow
- thinning of myometrium adjacent to placenta
- loss of hyperechoic uterine serosal boundary
- nodular projection of placental tissue beyond serosal margin (most specific sign, least commonly found)
- numerous placental lakes
Small placentas are associated with what? (6)
- IUGR
- toxemia of pregnancy
- maternal hypertension
- chromosomal abnormality
- severe maternal diabetes
- intrauterine infection
What conditions are most commonly associated w/ thick placenta? (10)
(>4cm in second trimester, or >6 in third)
- maternal diabetes mellitus
- maternal anemia
- fetal growth restriction
- aneuploidy + trisomy + triploidy
- hydrops fetalis
- infections
- hydatidiform mole
- intraplacental hermorrhage
- villitis
- beckwith-wiedemann syndrome
Cephalic index of 61% suggests which head shape?
Dolichocephaly (too long and narrow)
What is a vitelline duct? (omphalomesenteric duct)
Initially maintains a connection b/w yolk sac and embryo once diverged from each other
(contains artery and vein for nutrients and blood are transported)
When should you not see a grade III placenta?
Before 35-37 weeks
Patient has positive pregnancy test, presents with bleeding and cramping. What sonographic finding makes you suspect an impending inevitable abortion?
Dilated cervix
Once the cervix dilates, abortion will occur.
In the presence of placenta accreta, what space will look abnormal?
Retroplacental
The primitive hindbrain can be seen as a cystic structure within the embryonic head - what is the name of this structure?
Rhombencephalon
(appears prominent at 8wks)
If the Rhombencephalon is prominent after second trimester, what malformation is occurring?
Possible Dandy-Walker malformation
When there is no embryo present, you can calculate gestational age in weeks by measuring mean sac diameter and adding what number to it?
*(First half of first trimester only)
3
MSD (mm) + 3 = gestational age
What term refers to an accessory placental lobe?
Succcenturiate
What is the angle of asynclitism referring to?
The tilt of the fetal head in utero
You measure abdominal circumference at the level of the…?
Portal sinus and fetal stomach
