AMNIOTIC FLUID Flashcards
Membranous sac that surrounds the fetus
Amnion
Primary functions of amniotic fluid:
- Provide protective cushion for fetus
- Allow fetal movement
- Stabilize temperature to protect fetus from extreme temperature changes
- Permit proper lung development
The absorption of amniotic fluid water and solutes into the fetal vascular system is termed as ____________.
Intramembranous flow
TRUE or FALSE:
Amniotic fluid volume is regulated by a balance between the production of fetal urine and lung fluid and the absorption from fetal swallowing an intramembranous flow.
TRUE
Amount of amniotic fluid during the third trimester of pregnancy
800-1200 mL
The amount of amniotic fluid (increases/decreases) in quantity throughout pregnancy and then (increases/decreases) prior to delivery.
Increases; decreases
Amniotic fluid volume of >1200 mL is termed __________.
Polyhydramnios
Amniotic fluid volume of <800 mL is termed __________.
Oligohydramnios
TRUE or FALSE:
Cases of polyhydramnios and oligohydramnios may both result in some falsely low or falsely high analytes.
TRUE
Average amniotic fluid volume
1000 mL
During the first trimester, what is the approximate volume of amniotic fluid that come from the maternal circulation?
35 mL
During each episode of fetal respiratory movement, secreted lung liquid enters the amniotic fluid, bathing the lungs and washing pulmonary and alveolar contents such as _________, __________, and ___________. These lung surfactants also serve as index of fetal lung maturity.
Lecithin
Sphingomyelin
Phosphatidyl glycerol
This is the primary contributor to the amniotic fluid volume after the first trimester
Fetal urine
TRUE or FALSE:
When fetal urine production occurs, fetal swallowing of amniotic fluid also begins.
TRUE
Polyhydramnios or Oligohydramnios:
Failure of fetal swallowing
Polyhydramnios
Note: Failure of the fetus to begin swallowing results in excessive accumulation of amniotic fluid
Polyhydramnios or Oligohydramnios:
Excessive fetal swallowing
Oligohydramnios
Polyhydramnios or Oligohydramnios:
Associated with neural tube disorders
Polyhydramnios
Polyhydramnios or Oligohydramnios:
May be caused by urinary tract deformities and membrane leakage
Oligohydramnios
The ultimate source of amniotic fluid water and solutes
Placenta
TRUE or FALSE:
Amniotic fluid has a composition similar to maternal plasma
TRUE
Biochemical markers for neural tube defects
Alpha-fetoprotein
Acetylcholinesterase
When fetal urine production begins, the amniotic fluid composition changes. Indicate whether the indicated analyte will INCREASE or DECREASE:
Creatinine
INCREASE
When fetal urine production begins, the amniotic fluid composition changes. Indicate whether the indicated analyte will INCREASE or DECREASE:
Urea
INCREASE
When fetal urine production begins, the amniotic fluid composition changes. Indicate whether the indicated analyte will INCREASE or DECREASE:
Uric acid
INCREASE
When fetal urine production begins, the amniotic fluid composition changes. Indicate whether the indicated analyte will INCREASE or DECREASE:
Glucose
DECREASE
When fetal urine production begins, the amniotic fluid composition changes. Indicate whether the indicated analyte will INCREASE or DECREASE:
Protein
DECREASE
TRUE or FALSE:
Upon production of fetal urine, concentrations of electrolytes, enzymes, hormones, and metabolic end-products in the amniotic fluid also vary and are highly significant.
FALSE
Note: They are of little significance
Which particular analyte in the amniotic fluid may be used to determine fetal age?
Creatinine
Amniotic fluid creatinine level prior to 36 weeks’ gestation
1.5 – 2.0 mg/dL
Amniotic fluid creatinine level at >36 weeks’ gestation
> 2.0 mg/dL
Analytes that may aid in the differentiation between amniotic fluid and maternal urine
Creatinine
Urea
Glucose
Protein
Note:
Creatinine & Urea: More reliable
Glucose & Protein: Less reliable
Levels of creatinine and urea are (higher/lower) in amniotic fluid than in urine.
Lower
Creatinine levels in amniotic fluid
<3.5 mg/dL
Urea levels in amniotic fluid
<30 mg/dL
Creatinine levels in maternal urine
As high as 10 mg/dL
Urea levels in maternal urine
As high as 300 mg/dL
Presence of glucose, protein, or both is associated more closely with (amniotic fluid/maternal urine).
Amniotic fluid
This is a test that can differentiate amniotic fluid from urine and other body fluids. It can also be used to evaluate premature rupture of the membranes.
In this test, vaginal fluid specimen is spread on a glass slide, completely air-dried at RT, and observed microscopically.
Fern test
In performing fern test, the vaginal fluid specimen spread on a glass slide must be completely air-dried at what condition/temperature?
A. Refrigerated
B. Frozen
C. Room temperature
C. Room temperature
The presence of fern-like crystals that is considered a positive screen for amniotic fluid is composed mainly of ____________.
Protein
Sodium chloride
Process of collection of amniotic fluid
Amniocentesis
In general, amniocentesis is a safe procedure, particularly when performed after the ______ week of gestation.
14th
When testing for chromosome analysis, amniotic fluid is usually collected at approximately ________ week of gestation.
16th
At what part of pregnancy is amniocentesis performed when testing for intrauterine growth retardation?
Near the end of 2nd trimester
At what part of pregnancy is amniocentesis performed when testing for fetal distress and maturity?
3rd trimester
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Mother is ≥35 years old at delivery
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Family history of chromosome abnormalities
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Earlier pregnancy or child with birth defect
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Parent is a carrier of metabolic disorder
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Family history of genetic diseases
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Elevated maternal serum AFP
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Abnormal triple marker screening test
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Previous child with neural tube disorder
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Three or more miscarriages occurred
15-18 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
To detect fetal lung maturity
20-42 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Evaluate fetal distress
20-42 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Evaluation of HDN caused by Rh blood type incompatibility
20-42 weeks’ gestation
Determine whether amniocentesis is performed at 15-18 WEEKS’ GESTATION or 20-42 WEEKS’ GESTATION:
Check for infection
20-42 weeks’ gestation