AUBF-Lec-Amniotic fluid Flashcards
Primary Function of Amniotic Fluid
• Cushion for the fetus
• Allows fetal movement
• Stabilizes temperature
• Proper lung development
AMNIOTIC FLUID VOLUME is from
From fetal urine and lung fluid
NORMAL AMNIOTIC FLUID VOLUME
800-1,200 mL (3rd trimester)
major contributor to the AF volume after the 1st trimester of pregnancy
FETAL URINE
INCREASE AMNIOTIC FLUID VOLUME (>1,200 mL)
POLYHYDRAMNIOS
Causes of POLYHYDRAMNIOS
Decreased fetal swallowing of urine
Neural tube defects
Others: fetal structural anomalies, cardiac arrhythmias, congenital infections, chromosomal abnormalities
DECREASE AMNIOTIC FLUID VOLUME (<800 mL)
OLIGOHYDRAMNIOS
Causes of OLIGOHYDRAMNIOS
Increased fetal swallowing of urine Membrane leakage
Urinary tract deformities
Others: congenital malformations, premature amniotic membrane rupture, umbilical cord compression
Method of Collection for AF
Amniocentesis (up
tom 30 mL collected in sterile syringe)
Assess genetic defects (Ex. Trisomy 21/Down syndrome)
2nd trimester amniocentesis
fetal lung maturity (FLM), Fetal hemolytic disease (HDN)
3rd trimester amniocentesis
QUADRUPLE SCREENING TESTS PRIOR TO PERFORMING AMNIOCENTESIS
• Alpha-fetoprotein (AFP)
• Human chorionic gonadotropin (hCG) • Unconjugated estriol (UE3)
• Inhibin A
Specimen Handling Test for Fetal Lung Maturity (FLM):
• Place on ice on delivery
• Kept refrigerated or frozen
• Filtration=prevents loss of phospholipids
Specimen Handling Test for Cytogenetic studies:
Kept at room temperature or at 37°C
Specimen Handling Test for Hemolytic Disease of the Newborn (HDN):
Protected from light
Detects ruptured amniotic membranes
Also used to diagnose early pregnancy (Increase estrogen)
Fern Test
Fern Test Procedure
Specimen (Vaginal Fluid)
Slide (air dry)
(+) Fern-like crystals –Amniotic Fluid
AMNIOTIC FLUID
LESS RELIABLE
• Protein
• Glucose
MORE RELIABLE
• Urea (mg/dL)
• Creatinine (mg/dL)
+
+
<30
<3.5
MATERNAL URINE
LESS RELIABLE
• Protein
• Glucose
MORE RELIABLE
• Urea (mg/dL)
• Creatinine (mg/dL)
> 300
10
Amniotic fluid color: colorless
Amniotic fluid color: blood streaked
Amniotic fluid color: yellow
Amniotic fluid color: dark green
Amniotic fluid color: dark red brown