Amniotic Fluid Flashcards by Joo Ary

This a colorless to Pale-yellow fluid found in the membranous sac around the fetus called as AMNION

AMNIOTIC FLUID

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What are the functions of Amnionic Fluid?

FUNCTIONS:
1. Cushion for fetus
2. Allows fetal movement
3. Stabilizes temperature
4. Proper lung development

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What is the normal value of Amniotic Fluid?

NORMAL VOLUME: 800 to 1,200 mL [3rd trimester]

Note:
▪ Increases throughout pregnancy
▪ Gradually decreases before delivery

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What is the ultimate source of amniotic fluid water and solutes?

PLACENTA

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What trimester does a 35 mL is derived from the circulation coming from the mother?

1st trimester

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After the 1st trimester, the major constituent of amniotic fluid is?

FETAL URINE

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The fetus already released LUNG FLUID, which may contribute to the volume of the amniotic fluid

During the 3rd trimester:

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During the 3rd trimester of pregnancy, fetus release what kind of fluid? Which contributes to the volume of the amniotic fluid?

LUNG FLUID

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The normal volume of the amniotic fluid is regulated by the balance of:
Production of:

Fetal urine and Lung fluid

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The normal volume of the amniotic fluid is regulated by the balance of:

Absorption of Amniotic fluid by:

▪ Fetal swallowing
▪ Intramembranous flow

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▪ ↑ in the normal volume of amniotic fluid
▪>1,200mL
▪ ↓ fetal swallowing of urine
▪ Neural tube defects

POLYHYDRAMNIOS

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▪ ↓ in the normal volume of amniotic fluid
▪ <800mL
▪ ↑ fetal swallowing of urine
▪ Membrane leakage
▪ Urinary tract deformities*

OLIGOHYDRAMNIOS

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Deformities in Urinary Tract impairs urination thus

Decreases urine output [decreased urine output also indicates decreased amniotic fluid]

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What is the method collection of Amniotic Fluid?

Amniocentesis

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This safe to perform among pregnant women on the 14th week of gestation [early 2nd trimester]

Amniocentesis

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Amniocentesis is safe to perform among pregnant women on the what time frame?

14th week of gestation [early 2nd trimester]

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The MAXIMUM VOLUME of Amniocentesis is?

30 mL

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The first 2 to 3 mL is discarded because it may be contaminated with:

▪ Maternal Blood
▪ Tissue Fluid
▪ Cells

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Can be assessed for Chromosomal Studies e.g. Trisomy 21 / Down Syndrome

16th week / 2nd Trimester Amniocentesis

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Assessment of Fetal Lung Maturity and Fetal Hemolytic Disease

3rd Trimester Amniocentesis

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The specimen must be placed on ICE during delivery
IF not performed immediately, must be refrigerated

Test for Fetal Lung Maturity (FLM)

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Must the kept at room temperature or Body temperature

Test for Cytogenetic Studies / Microbial Studies

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For detection of Bilirubin, a photosensitive analyte thus, it must be protected from light by using:
▪ Amber colored bottle
▪ Foil
▪ Black Plastic cover

Test for HDN

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For detection of Bilirubin, a photosensitive analyte thus, it must be protected from light by using:

▪ Amber colored bottle
▪ Foil
▪ Black Plastic cover

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There may be a possibility of _________ of the urinary bladder of the mother

accidental puncture

PROTEIN (+) GLUCOSE (+) UREA <30 mg/dL CREATININE <3.5 mg/dL

Amniotic Fluid

PROTEIN (-) GLUCOSE (-) UREA >30 mg/dL CREATININE >10 mg/dL

Maternal Urine

Why Protein and Glucose are less reliable as compared to Urea and Creatinine?

If the mother has conditions e.g. Proteinuria or Glucosuria, Maternal Urine may be False Positive (+)

Detects ruptured amniotic membranes

FERN TEST

What is specimen used in FERN TEST?

Vaginal Fluid

What are the procedures in FERN TEST?

PROCEDURE: 1. Spread on a glass slide 2. Allowed to air dry at room temperature 3. Observe under the microscope

Amniotic Fluid appears as Fern Like Crystals

Due to protein and NaCl present on Amniotic Fluid

AMNIOTIC FLUID COLOR: Colorless to Pale- Yellow

Normal

AMNIOTIC FLUID COLOR: Blood-Streaked

Traumatic tap Abdominal Trauma Intra-amniotic Hemorrhage

AMNIOTIC FLUID COLOR : Yellow

↑ Bilirubin [HDN]

AMNIOTIC FLUID COLOR: Dark Green

Meconium [1st fetal bowel movement]

AMNIOTIC FLUID COLOR: Dark Red-brown

Fetal Death / Fetal Demise

What are the test in AMNIOTIC FLUID?

Test for HDN Test for Neural Tube Defects Test for Fetal Lung Maturity Test for Fetal Age

Anti-D antibodies that can destroy large numbers of fetal RBCs Results in RBC degradation product e.g. Bilirubin

HDN / ERYTHROBLASTOSIS FETALIS

a.k.a Optical density 450

Test for HDN

Absorbance of Amniotic Fluid:

▪ NORMAL: ↑365 nm, ↓550 nm ▪ HDN: ↑450 nm [maximum bilirubin absorbance]

Results on HDN TEST are plotted on a what graph?

LILEY GRAPH

Nonaffected / mildly affected fetus

Zone 1

Moderately affected fetus ▪ Close monitoring is required

Zone II

Severely affected fetus ▪ Requires intervention

Zone III

What are the interferences on HDN TEST?

INTERFERENCES: ▪ Presence of cells / meconium ▪ Presence of debris ▪ Presence of hemoglobin [410 nm peak absorbance]

Birth defect where there is incomplete closing of the backbone and membranes around the spinal cord.

SPINA BIFIDA / SPLIT SPINE

Absence of major portion of the brain and scalp

ANENCEPHALY

Major protein produced by Fetal Liver during early gestation [18th week] Screening Test

ALPHA-FETOPROTEIN (AFP)

AFP is increased in?

Spina Bifida, Anencephaly ▪ Both Amniotic Fluid and Maternal Serum increase during pregnancy ▪ AFP will continuously increase if the skin fails to close the Neural Tissues

AFP is decreased in?

Down Syndrome

CONFIRMATORY TEST: ▪ Must not be performed if the sample is bloody ▪ Blood contains AcHE = False ↑ in Amniotic Fluid

Acetylcholinesterase (AChE)

Most frequent complication of early delivery 7th most common cause of morbidity and mortality among premature infants

RESPIRATORY DISTRESS SYNDROME

RESPIRATORY DISTRESS SYNDROME is caused by insufficient?

LUNG SURFACTANTS [Phospholipids]

Main analyte measured in Amniotic Fluid to check for Lung Maturity It allows the alveoli to open and close during inhalation and exhalation

LUNG SURFACTANTS [Phospholipids]

TESTS FOR NEURAL TUBE DEFECTS

ALPHA-FETOPROTEIN (AFP)

TESTS FOR FETAL LUNG MATURITY

LECITHIN / SPHINGOMYELIN (L/S) RATIO AMNIOSTAT-FLM FOAM TEST / SHAKE TEST MICROVISCOSITY LAMELLAR-BODY COUNT OD 650 nm

This the Reference Method

LECITHIN / SPHINGOMYELIN (L/S) RATIO

Primary component of Lung surfactant; A phospholipid; Low production during the 35th week and below however, after 35th week, its production increases

LECITHIN

Produced at a constant rate; Control

SPHINGOMYELIN

↓Lecithin; ↑Sphingomyelin

35th week and below

↑Lecithin; ↓Sphingomyelin

After 35th week

<35th week

<1.6 L/S Ratio

Mature fetal lungs → Preterm delivery is safe

≥2.0 L/S Ratio

Presence of Blood and Meconium

False Increase

Immunologic test for PHOSPHATIDYLGLYCEROL The production of Phosphatidylglycerol is parallel to the production of Lecithin Advantage: Not affected by Blood and Meconium Disadvantage: Production is ↓ among Diabetic mothers

AMNIOSTAT-FLM

A mechanical test in assessing Fetal Lung Maturity

FOAM TEST / SHAKE TEST

Amniotic Fluid + 95% ethanol ————> stand for 15 mins

Shake for 15 seconds

Presence of Foam / Bubbles ▪ Indicates sufficient Phospholipid present in the Amniotic Fluid

Mature Fetal Lung

A modification of Foam Test

FOAM STABILITY INDEX

0.5 increasing amount of shake for 15 secs + 95% ethanol ————————> Stand for 15 mins Amniotic Fluid (0.47 - 0.55 mL) Mature Fetal Lung:

A semi-quantitative test Foam / Bubbles = ≥0.47 indicates MFL

Measured by Fluorescence Polarization Surfactant-to-Albumin (S/A) Ratio is measured: ↑Phospholipid, ↓ Microviscosity Dye Bound to Albumin: ↓Fluorescence, ↑Polarization Dye Bound to Surfactant: ↑Fluorescence, ↓Polarization

MICROVISCOSITY

Stored form of Phospholipid in the fetus

LAMELLAR-BODY COUNT

This one is produce lung surfactants stored in the form of LAMELLAR BODIES

Type II Pneumocytes

METHODS: (LAMELLAR-BODY COUNT) ▪ Diameter of Lamellar Bodies is similar to the diameter of Platelets which is why we can use the platelet channel of Hematology analyzer

Impedance, Optical Scatter Methods

LAMELLAR-BODY COUNT Adequate Fetal Lung Maturity:

>32,000 /uL

↑ Lamellar Bodies = ↑ Optical Density OD of ≥0.150 is equivalent to: L/S Ratio: >2.0 [indicates mature fetal lung] Presence of: Phosphatidyl Glycerol

OD 650 nm

AMNIOTIC FLUID CREATININE

TEST FOR FETAL AGE

<36 weeks gestation: 1.5 to 2.0 mg/dL 36 weeks gestation: >2.0 mg/dL

AMNIOTIC FLUID CREATININE

Amniotic Fluid Flashcards

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