Amniotic Fluid and Normal Placenta Flashcards
What is considered a dialysate of maternal serum?
Amniotic fluid
What is considered essential for the tracheobronchial tree?
Amniotic fluid
What is seen in the amniotic fluid that resembles debris in the third trimester?
Vernix
How much urine does the fetus produce in the third trimester?
450mL per day
If you see 40mL of amniotic fluid at 12 weeks, is this normal?
No. At 12 weeks, you should see 60mL of amniotic fluid
How much amniotic fluid should be seen at 20 weeks?
500mL
How are fetal fluid volumes maintained beginning at 20 weeks GA?
Swallowing and urination
During how many weeks is amniotic fluid a subjective assessment only?
1st and 2nd trimester
During what weeks should abnormal fluid levels be reported with a SDP?
18w-26w, 6d
When performing an SDP, what is the width and height of the rectangular box that should be free of cord or fetal parts?
1cm width
2cm height
On a routine 18-20 week detailed assessment, if we do not see fetal sex, what should we do?
Never schedule a follow up for the sole purpose of determining fetal sex
Measurements for SDP?
Oligo = <2cm
Normal = 2-8cm
Poly = >8cm
Measurements for AFI?
Oligo = <5cm
Normal = 5-25cm
Poly = >25cm
T or F? Both oligo and polyhadramnios can be idiopathic?
True
Causes of oligohydramnios?
- Uteroplacental insufficiency
- IUGR
- Postterm pregnancy
- PROM
Causes of polyhydramnios?
- Maternal diabetes
- Multiple gestations
- Fetal Anemia
What carries oxygenated blood from the placenta to the fetus?
Umbilical vein
What carries deoxygenated blood from the fetus back to the placenta?
Umbilical arteries
What does the umbilical cord originate from?
Fusion of the yolk sac stalk and omphelomesenteric duct at 7 weeks
What endometrial layer forms the maternal placenta?
Decidua basalis
What is the fetal side of the placenta?
Chorion frondosum
What can the placenta synthesize?
Sugars, fats, hormones
What placental measurement is considered abnormal?
> 4 cm prior to 24 weeks
What is the term for when the umbilical cord is eccentrically near the margins?
Battledore
What is the term when the umbilical cord inserts below the edge of the placenta?
Velamentous
What may cause the findings of large vascular spaces in the placenta?
Increased AFP
What is the most common placental location?
Anterior
What is the RPC composed of?
Decidua basalis and portions of myometrium
What type of RPC location can cause excessive bleeding due to amniocentesis?
Anterior
What type of RPC location can cause large venous channels within the complex?
Posterior due to gravity over-distending the veins
