Amniotic Fluid Flashcards
Formation of fluid through time of pregnancy
Placental
Early pregnancy: diasylate of mother’s plasma
Later: more fetal urine and waste
Flow and volume of amniotic fluid
- Bidirectional flow, nutrients too, 2-3 hour exchange
Volume: increases during pregnancy
- 25-50mls - 12 weeks
- 1100-1500 mls - 36 weeks
Hydramnios and effects
> 2000mls
- decreased fetal swallowing
- mothers with diabetes
Oligohydramnios and effects
<300mls fluid
- pacental insufficiency
- congenital malformations
- membrane rupture
Collection phases during pregnancy
What is collection called?
Amniocentesis
15-18 weeks: genetic testing
3rd trimester: FLM testing
- 10-20 mls
- first 1-2 mls discarded
Differentiate amniotic fluid and urine
Urine: more urea and creatinine
Amniotic fluid: more protein and glucose
Yellow/amber fluid
Bilirubin, HDFN
Green fluid
Meconium
Dark red/brown fluid
Dead fetal tissue
Pinkish to red
Blood
Turbidity changes with time?
Gets more turbid as pregnancy progresses due to fetal cells, hair, and debris
Fetal lung maturity importance
fetus lacks enough surfactant in lungs to inhale/exhale
Phospholipids FLM testing
Lecithin”sphingomyelin ratio
- 0-33 weeks L=S
- After L>S
- Ratio of >= 2.0 is mature
Phosphatidyglycerol
- If detected after 35 weeks, mature
- Delayed production in diabetes
Lamellar bodies FLM testing
They store fetal lung surfactants
50-200k/uL
- 35k = mature
Fetal distress testing
Mom has Abs against fetal RBCs
“Erythroblastosis fetalis”
