amniotic fluid Flashcards
frequently associated w/ cytogenetic analysis.
Amniotic fluid exam
it is a product of fetal metabolism
amniotic fluid
amniotic fluid is present in a membranous sac that surrounds the fetus called ____
amnion
FUNCTIONS OF AMNIOTIC FLUID
1) To provide a protective cushion for the fetus
2) Allow fetal movement
3) Stabilize temperature to protect the fetus from extreme temperature changes
4) To permit proper lung development.
Amniotic fluid volume is regulated by a balance between the production of ________ & the absorption from _________-.
fetal urine & lung fluid ; fetal swallowing & intramembranous flow
absorption of amniotic fluid water and solutes into the fetal vascular system.
Intramembranous flow
The amount of amniotic fluid increases throughout ________, reaching a peak approximately ______ during the 3rd trimester, & then gradually decreases prior to ______.
pregnancy ; 1 liter ; delivery
During the 1st trimester, the approximately _____ of A.F derived primarily from the _______.
35ml/g ; maternal circulation
After the 1st trimester, _______ is the major contributor to the A.F. volume.
Fetal urine
When fetal urine production occurs, fetal swallowing of A.F. ______ & _____ the increase in fluid from the fetal urine.
begins ; regulates
excessive accumulation of A.F. resulting from the failure of the fetus to begin swallowing.
Polyhydramnios
Polyhydramnios indicates ________, often associated w/ _________.
fetal distress ; neural tube disorders
decreased A.F. due to increase fetal swallowing, urinary tract deformities, & membrane leakage.
Oligohydramnios
Oligohydramnios is associated with ______, resulting in __________-.
umbilical cord compression ; decelerated heart rate & fetal death.
Ultimate Source of AF & solutes.
PLACENTA
Amniotic fluid has a composition similar to that of the maternal plasma and contains a small amount of sloughed fetal cells from the ____
DUS (Digestive system, Urinary tract, Skin)
Amniotic fluid also contains Biochemical substances produced by the fetus, such as _____
BELPEN (Bilirubin, Enzymes, Lipids, Proteins, Electrolytes, Nitrogenous compounds)
BELPEN can be tested to ______
determine the health or maturity of the fetus.
used to determine fetal age.
creatinine measurement
Prior to 36 weeks gestation , the amniotic fluid creatinine level ranges bet _______
1.5 and 2.0 mg/dl.
the amniotic fluid creatinine level rises above _____ providing a means of determining fetal age as greater than _____.
2.0 mg/dl ; 36 weeks
Levels of creatinine and urea are much lower in _____ than in _____.
amniotic fluid ; urine
AMNIOTIC FLUID: creatinine does not exceed _____; urea does not exceed _____.
3.5 mg/dl ; 30 mg/dl
URINE: as high as ______ for creatinine; and ______ for urea.
10 mg/dl ; 300 mg/dl
differentiate amniotic fluid from urine
Fern test
in Fern test, _____ specimen or smear is examined microscopically
Vaginal fluid
Fetal epithelial cells in AF can be examined for chromosome abnormalities by:
1) Karyotyping
2) Fluorescence in situ hybridization (FISH)
3) Fluorescent mapping spectral karyotyping (SKY)
4) DNA testing
Biochemical substances produced by the fetus can be analysed by ________ and _________ to evaluate the health of the fetus.
Fluorescence polarization ; Thin-layer chromatography
Amniocentesis may be indicated at 15-18 weeks of gestation to determine early treatment or intervention:
1) Mother’s age of 35 or more at delivery
2) Family history of chromosome abnormalities such as down
syndrome (trisomy 21)
3) Parents carry an abnormal chromosome rearrangement
4) Earlier pregnancy or child w/ birth defect
5) Parent is a carrier of metabolic disorder
6) History of genetic diseases such as:
- sickle cell disease
- sickle cell anemia
- tay sach disease
- hemophilia
- muscular dystrophy
- huntington chorea
- cystic fibrosis
7) Elevated maternal serum alpha fetoprotein
8) Abnormal triple marker screening test
9) Previous child w/ neural tube disorder such as spina bifida
or ventral wall defects
10) 3 or more miscarriages
Evaluation of amniocentesis is indicated later in pregnancy (______) to evaluate:
20-42 weeks
1) Fetal lung maturity
2) Fetal distress
HDN cause by Rh incompatibility
Infection
Amniocentesis (procedure) – is obtained by ______ into the ______ (transabdominal amniocentesis). Safe procedure.
needle aspiration ; abdominal sac
Using continuous _______ for guidance, the physician locates the _______ to safely perform the procedure.
ultrasound ; fetus and placenta
______ maybe performed but carries a greater risk of infection
vaaginal amniocentesis
amniocentesis volume collected in sterile syringes
30 ml
Fluid for bilirubin analysis in cases of _________ must be protected from light at all times.
Hemoytic disease of the
newborn (HDN)
specimen should be placed in ice for delivery to the lab
Fetal Lung Maturity (FLM) Tests
Fetal Lung Maturity (FLM) Tests specimen should be placed
in ice for delivery to the lab & refrigerated up to _____ prior to
testing or kept frozen & tested w/in _____
72 hrs ; 72 hrs.
maintained at room temp or body temp (37°c incubation) prior to analysis to prolong the life of the cells.
cytogenetic studies
cytogenetic studies temperature
room temp or body temp (37°c incubation)
All fluid for chemical testing should be separated from ______ as soon as possible to prevent distortion of chemical constituents by cellular metabolism or disintegration. This can be performed using ___________.
cellular elements & debris ; Centrifugation/filtration
recommended for FLM to prevent loss of
phospholipids.
Filtration
normal color of AF
colorless
yellow colored AF =
Presence of bilirubin
dark green colored AF =
Presence of meconium
newborn’s first bowel movement. Results for fetal intestinal secretions.
meconium
dark red-brown colored AF =
fetal death
blood streaked colored AF =
Result of a traumatic cap, abnormal trauma, & intra-amniotic hemorrhage.
in HEMOLYTIC DISEASE OF THE NEWBORN (HDN), Measurement of bilirubin in the AF determines the extent the
hemolysis. Performed by __________
Spectrophotometric Analysis.
determines the severity of the hemolytic disease
Liley Graph
Liley Graph interpretation
Zone I – mildly affected fetus
Zone II – require careful monitoring
Zone III – severely affected fetus
high levels of alpha-fetoprotein (AFP) in both the maternal
circulation & the AF indicates fetal neural tube defects, such as
________
anencephaly & spina bifida.
major CHON produced by the fetal liver during early gestation (prior to 18 weeks)
Alpha-fetoprotein (AFP)
more specific for neural tube disorders than AFP, provided it is not performed on a bloody specimen because blood contains AChE.
Amniotic acetylcholinesterase (AChE) test
Most frequent complication of early delivery & cause of
morbidity & mortality in the premature infant.
Respiratory Distress Syndrome (RDS)
Caused by a lack of lung surfactant, a substance that normally appears in mature lungs & allows the alveoli to remain open throughout the normal cycle of inhalation & exhalation.
Respiratory Distress Syndrome (RDS)
keeps the alveoli from collapsing by decreasing
surface tension & allows them to inflate w/ air more easily.
Surfactant
The reference method to which tests of FLM are compared is the __________ ratio
Lecithin-spingomyelin
primary component of the surfactants
Lecithin
Quantitative measurement of lecithin and sphingomyelin is
performed using _____________.
thin-layer chromatography
uses anti-sera specific for phosphatidyl glycerol and is not affected by specimen contamination with blood and meconium.
Amniostat-FLM
The presence of _________ decreases the micro viscosity of amniotic fluid.
Phospholipids
measure the polarization of a fluorescent dye that combines w/ both surfactants & albumin.
Fluorescence Polarization Assay
Low polarization, longer fluorescence lifetime =
dye bound to surfactant
(↑) High polarization, (↓) fluorescence lifetime =
dye bound to albumin
used as an internal standard in the same manner as sphingomyelin because it remains at a constant level throughout gestation.
Albumin
lamellated phospholipids that represent a storage form of surfactants.
Lamellar bodies
The surfactants responsible for FLM are produced & secreted by the _________ of the fetal lung & stored in the form of structures termed lamellas bodies of about ________.
type II pneumocytes ; 20 weeks of gestation
The lamellar bodies enter the _____ spaces to provide ______ & also enter the _________ at about __________.
alveolar ; surfactant ; amniotic fluid ; 26 weeks of gestation
As the fetal lung matures, ↑ lamellar body production is reflected by an ↑ in ______ & the ______.
AF phospholipids ; L/S ratio
The # of lamellar bodies present in the AF correlates w/ the amount of _______ present in the _______.
phospholipid ; fetal lungs
The presence of lamellar bodies increases the ______ of the AF
OD = optical density
A confirmatory procedure in testing for urinary CHON.
Sulfosalicylic Acid Test (SSA)
Sulfosalicylic Acid Test (SSA) is able to detect not only albumin but also _______, __________ & ___________.
globulin, mucoprotein & Bence Jones protein
A rapid screening method w/c is more sensitive to the presence of albumin than globin, mucoprotein & Bence Jones protein.
Reagent Strip Test
