FUNCTIONS OF AMNIOTIC FLUID
Ø Provide a protective cushion for the fetus
Ø Allows fetal movement
Ø Stabilize the temperature to protect the fetus from
extreme temperature changes
Ø Permits proper lung development
Volume during the 3rd trimester
Approx. 800-1200 ml
During the first trimester amniotic fluid is derived from
MATERNAL CIRCULATION
Accumulation of amniotic fluid due to fetus’ failure to swallow the urine
POLYHYDRAMNIOS
Disorder associated on abnormal increase of amniotic fluid
Fetal distress
Neural tube defects
Secondary effects like congenital infection and urinary tract deformities
Abnormal decrease of amniotic fluid
Oligohydramnios
Oligohydramnios associated with
Umbilical cord compression
Decelerated heart rate
Fetal death
Composition of amniotic fluid
Sloughed fetal cells from skin, digestive system and urinary tract
Biochemical substances of amniotic fluid
Bilirubin
Protein
Lipid
Enzyme
Nitrogen compound
Used to determine fetal age
Amniotic fluid creatinine
Crea level prior to 36 weeks of gestation
1.5 - 2.0 mg/dl
Crea level if > 36 weeks of gestation
2.0 mg/dl
Early (14-16 weeks)
Diagnosis of genetic diseases
Mid Trimester
Bile pigments level for HDN
Neural tube defects
3rd Trimester
Renal maturity
Bile pigments level for HDN
Amniotic fluid is contaminated with
Maternal blood
Tissue fluid
Cells
AMNIOTIC FLUID TESTS
Significance:
Detection of HDN
Detection of Fetal-lung maturity
Detection of Fetal-lung hypoxia
Detection of Fetal disorders
Detection of Cytogenic disorders
Detection of Chromosomal abnormalities
Blood streak
Traumatic tap, bdominal
trauma, intra-amniotic hemorrhage
Yellow
Hemolytic disease of the
newborn (bilirubin)
Dark green
Meconium
Dark red-brown
Fetal death
Produced at constant rate after about 26th week
of gestation
Sphingomyelin
Produced at relatively low & constant rate
until 35th week of gestation
Lecithin
Essential fluid for adequate lung maturity
Phosphatidyl glycerol
Phosphatidylinositol
