#3 amniotic fluid

acetylcholinesterase

(ACHE).

hemolytic disease of the newborn

(HDN)

30 mL

A maximum of ___________of amniotic fluid is collected in sterile syringes

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After the first trimester, fetal urine is the major contributor to the amniotic fluid volume. (In the second trimester, the fetal urine formation begins to contribute the volume and is a major contributor for the remainder of the pregnancy). :-)

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All fluid for chemical testing should be separated from cellular elements and debris as soon as possible to prevent distortion of chemical constituents by cellular metabolism or disintegrations This can be performed using centrifugation or filtration. However, u don't to centrifuge for fetal lung maturity test because it can cause loss of phospholipids!!!

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Amniotic fluid bilirubin is measured by spectrophotometric analysis using serial dilutions. :-)

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In general, amniocentesis is a safe procedure, particularly when performed after the 14th week of gestation. Fluid for chromosome analysis is usually collected at approximately 16 weeks' gestation and tests for intrauterine growth retardation are performed near the end of the second trimester, whereas tests for fetal distress and maturity are performed later in the third trimester. :-)

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Increased levels are found in the maternal serum and amniotic fluid when the skin fails to close over the neural tissue, fas occurs in anencephaly and spina bifida. ;-)

alpha-fetoprotein (AFP)

Increased levels of ___________in both the maternal circulation and the amniotic fluid can be indicative of fetal neural tube defects,

anencephaly and spina bifida.

Increased levels of alpha-fetoprotein (AFP) in both the maternal circulation and the amniotic fluid can be indicative of fetal neural tube defects, such as _________and _________

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Initial exposure to for- eign red cell antigens occurs during gestation, delivery of the placenta, or a previous pregnancy when fetal red blood cells enter into the maternal circulation and stimulate the mothet to produce antibodies to the antigen. :-)

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Intramembranous flow is the absorption of amniotic fluid water and solutes into the fetal vascular system. :-)

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It is found in the maternal serum due to the combined fetal-maternal circulations and in the amniotic fluid from diffusion and excretion of fetal urine. ;-)

Fetal lung maturity, fetal distress(HDFN), infection

LATER in pregnancy we want to do amniocentesis to detect what?

type II pneumocytes

Lamellar Bodies are secreted by the ________________of the fetal lung at about 24 weeks of gestation/and are absorbed into the alveolar spaces to provide surfactant.

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Mature lung will show an OD of 0.150 has been shown to correlate well with an L/S ratio of greater than or equal to 2.0 and the presence of phosphatidyl glycerol. :-)

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Measurement of amniotic fluid AFP levels is indicated when maternal serum levels are elevated or a family history of previous neural tube defects exists.

dark green,

Meconium, -> what color?

fetal distress.

Meconium, dark green, mucus-like material. may be present in the amniotic fluid as a result of___________

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Mother forms the antibody to foreign substance or antigen. The antibody has the ability to cross the placenta and attach to baby's RBCs. Then, antibody will bind to the RBCs and destroy them by hemolysis. :-) lead to an increase in unconjugated bilirubin which is detectable in amniotic fluid.

Alpha-fetoprotein and acetylcholinesterase

Neural tube defects allow fetal cerebrospinal fluid to enter the amniotic fluid directly. Results in an increase in _____________,_____________

colorless

Normal amniotic fluid is ____________________and may exhibit slight to moderate turbidity from cellular debris, particularly in later stages of fetal development.

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Normal values are based on the week of gesta- tional age, as the fetus produces maximal AFP between 12 and 15 weeks' gestation, after which levels in amniotic fluid begin to decline.

Phosphatidyl Glycerol (PG),

Presence of another lung surface lipid, ____________ is also essential for adequate lung maturity and can be detected after 35 weeks' gestation.

less than 1.6

Prior to 35 weeks' gestation, the L/S ratio is usually _______________because large amounts of lecithin are not being produced at this time.

Creatinine >2.0 mg/dL

Prior to 36 weeks' gestation, the amniotic fluid creatinine level ranges between 1.5 and 2.0 mg/dL. It then rises to ________________ providing a means of determining fetal age greater than 36 weeks

Provide information about metabolic process, provide information of fetal maturation, provide information about fetal distress

Purpose of analyzing amniotic fluid

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SPECIMEN COLLECTION reasons for amniocentesis > early in pregnancy •mom > 35 years of age • history of chromosomal abnormalities in the family or parents know to be a carrier of metabolic disorder • previous child with birth defect • increased maternal serum alpha fetoprotein or triple marker screening • previous child with spina bifida • 3 or more miscarriages

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Specimen Handling and Processing Handling and processing of amniotic fluid vary with the tests enter requested and with the methodology used by the laboratory performing the teşt. However, in all circumstances, special han- dling procedures should be performed immediately and the fetal specimen delivered promptly to the laboratory. :-)

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Specimens for bilirubin testing must be immediately protected from light. This can be/ accomplished by placing the specimens in amber-colored tubes, wrapping the collection tube in foil, or by use of a black plastic cover for the specimen container

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Specimens for cytogenetic studies or microbial studies must be processed aseptically and maintained at room temperature or body temperature (37°C incubation) prior to analysis to prolong the life of the cells needed for analysis.

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Surfactant keeps the alveoli from collapsing by decreasing surface tension and allows them inflate with air more easily. If the surfactant concentrations are too low, the alveoli will collapse, causing RDS. :-)

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Surfactant normally appears in mature lungs and allows the alveoli (air sacs of the lung) to remain open throughout the normal cycle of inhalation and exhalation.

Hemolytic Disease of the Newborn, neural tube defects

Tests for Fetal Distress

Fetal lung maturity, lecithin-sphingomyelin ratio, Lamellar Bodies, Phosphatidyl Glycerol, Foam Stability Index,

Tests for Fetal Maturity

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Tests for Fetal Maturity Fetal distress, whether caused by HDN or other conditions, forces the obstetrician to consider a preterm delivery. At this point, fetal maturity must be assessed. :-)

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The Foam Stability Index -The test cannot be used with contaminated amniotic fluid because blood and meconium also reduce surface tension, yielding a falsely mature index result.

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The L/S ratio will rise to 2.0 or higher as the lecithin production increases to prevent alveolar collapse. Therefore, when the L/S ratio reaches 2.0, a pretern delivery is usually considered to be a relatively safe procedure.

450 nm

The difference between the OD of the theoretic baseline and the OD at ___________represents the amniotic fluid bilirubin concentration.

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The first 2 or 3 mL collected can be contaminated by maternal blood, tissue fluid, and cells and are discarded. Specimens should be transferred to sterile plastic containers and taken immediately to the laboratory. ;-)

bilirubin, lipids, enzymes, electrolytes, urea, creatinine, uric acid, proteins, and hormones

The fluid contains that are produced by the fetus, such as _______,________,_________,________,_______,_________,________, _________, ________, (give 9)that can be tested to determine the health or maturity of the fetus.

yellow color

The presence of bilirubin gives the fluid a ________________and is indicative of red blood cell destruction resulting from HDN.

HDN.

The presence of bilirubin gives the fluid a yellow color and is indicative of red blood cell destruction resulting from___________

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The presence of lamellar bodies increases the OD ofe the amniotic fluid. Specimens are centrifuged at 2000 g for 10 minutes and examined using a wavelength of 650 nm

Transabdominal

The procedure is usually a _____________amniocentesis using a guidance from the ultrasound.

maternal diabetés.

The production of PG can be delayed in cases of________________

Kleihauer-Betke test

The source of the blood (maternal or fetal) can be determined using the _____________________for fetal hemoglobin

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This difference in OD, is then plotted on a Liley graph to determine the severity of the hemolytic disease :-)

Respiratory distress syndrome (RDS)

This disease is caused by an insufficiency of lung surfactant production and structural immaturity of the fetal lungs.

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Using continuous ultrasound for guidance! the physician locates the fetus and placenta to safely perform the procedure. A thin, hollow needle is inserted through the mother's abdomen into the mother's uterus and into the amniotic sac to aspirate the amniotic fluid. :-)

infection

Vaginal amniocentesis may also be performed; however, this method carries a greater risk of___________

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We can collect amniotic fluid to perform cytogenetic analysis :-)

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When these antibodies present in the maternal circulation cross the placenta into the fetal circulation and bind to the antigen on the fetal cells, the cells are destroyed. :-)

optical density (OD) of the fluid

________________ of the fluid is measured in intervals between 365 nm and 550 nm and the readings plotted on semilogarithmic graph paper

Respiratory distress syndrome (RDS)

_____________________________is the most frequent complication of early delivery and is the seventh most common cause of morbidity and mortality in the premature infant.

Sphingomyelin

___________________can serve as a control on which to base the rise in lecithin Both lecithin and sphingomyelin appear in the am niotic fluid in amounts proportional to their concentrations in the fetus.

very dark red-brown fluid

_______________is associated with fetal death

AFP

_____________is the major protein produced by the fetal liver during early gestation (prior to 18 weeks).

Amniotic fluid

___________present in the amnion a membranous sac that surrounds the fetus

Sphingomyelin

__________is a lipid that is produced at a constant rate after about 26 weeks' gestation

800 to 1200 mL

amount of amniotic fluid increases in quantity throughout pregnancy, reaching a peak of approximately ___________________during the third trimester, and then gradually decreases prior to delivery.

Lamellar Bodies

are densely packed layers of phospholipids that represent a storage form of pulmonary surfactant.

Neural tube defects (NTD)

are one of the most common birth defects in the United States. It can be detected by maternal serum alpha-fetoprotein (MSAFP) blood test, high-resolution ultrasound, and amniocentesis.

Lamellar Body Count

can be obtained using the platelet channel of automated hematology analyzers using either optical or impedance methods for counting.

Foam Stability Index

can be performed at thel bedside or in the laboratory,

oligohydramnios

decreased amniotic fluid

Lamellar Bodies

enter the amniotic fluid at about weeks of gestation and increase in concentration from 50,000 to 200,000 per microliter by the end of the third trimester.

polyhydramnios

excessive accumulation of amniotic fluid

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fetal swallowing of the amniotic fluid begins and regulates the increase in fluid from the fetal urine. The fetus swallows amniotic fluid, which is absorbed through the gastrointestinal tract and reexcreted by the kidneys from the blood into fetal urine and back into amniotic fluid. :-)

between the production of fetal urine and lung fluid and the absorption from fetal swallowing and intramembranous flow.

Amniotic fluid volume is regulated by a balance between what?

creatinine, urea, and uric acid

As would be expected, the chemical composition of the amniotic fluid changes when fetal urine production begins. The concentrations of __________,_________,___________ increase)

traumatic tap, abdominal trauma, or intraamniotic hemorrhage.

Blood-streaked fluid may be present as the result of a_____________,_____________ or ______________

Hemolytic disease of the newborn (HDN)

Caused by mother exposure to antigen

amniocentesis

Collected by needle aspiration into the amniotic sac.

:-)

Differentiating Maternal Urine From Amniotic Fluid Differentiation between amniotic fluid and maternal urine may be necessary to determine possible premature membrane rupture of the maternal bladder during or accidental puncture specimen collection. Levels of creatinine are much lower in amniotic fluid than in urine. :-)

lecithin, sphingomyelin, and phosphatidyl glycerol

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_______________ into the amniotic fluid surrounding the fetus. These lung surfactants serve as an index of fetal lung maturity.

Mom's (maternal)

During the first trimester, the amniotic fluid is derived primarily from the _____________circulation.

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During the latter third to half of pregnancy, the fetus secretes a volume of lung liquid necessary to expand the lungs with growth. ;-)

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Elevated amniotic fluid AFP levels are followed by measurement of amniotic acetylcholinesterase (ACHE). The test is more specific for neural tube disorders than AFP, provided it is not performed on a bloody specimen, because blood contains ACHE. :-)

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Failure of the fetus to begin swallowing results in excessive/ accumulation of amniotic fluid (polyhydramnios) and is an indication of fetal distress, often associated with neural tube disorders) ;-)

Blood or meconium

Falsely elevated results are encountered in fluid contaminated with _________or__________because both these substances contain lecithin and sphingomyelin.

:-$

Fetal aspiration of meconium during fetal swallowing is a concern when increased amounts are present in the fluid. ;-)

fetal lung maturity (FLM)

Fluid for ____________________tests should be placed in ice for delivery to the laboratory and kept refrigerated.

bubbles

Foam Stability Index -Amniotic fluid is mixed with 95% ethanol, shaken for 15 seconds, and allowed to sit undisturbed for 15 minutes the surface of the fluid is observed for the presence of a continuous line of ____________around the outside edge.

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Hemolytic Disease of the Newborn (HDN) caused by mother exposure to antigen • found on baby's RBCs

Foam Stability Index

has shown good correlation with the L/S ratio and tests for phosphatidyl glycerol.

amnion

is metabolically active and is involved in the exchanges of water and chemicals between the fluid, the fetus, and the maternal circulation and produces peptides, growth factors, and cytokines.

Lecithin

is produced at a relatively low and constant rate until the 35th week of gestation, at which time a noticeable increase in its production occurs, resulting in the stabilization of the fetal lung alveoli.

phospholipids

lecithin-sphingomyelin (L/S) ratio measure the ____________ that are present in amniotic fluid.

<800 mL

oligohydramnios-> amniotic fluid ____________how much?

>1200mL

polyhydramnios-> amniotic fluid _____________how much?

Increased fetal swallowing, urinary tract deformities, and membrane leakage

possible causes of decreased amniotic fluid (oligohydramnios) give 3

➡️to provide a protective cushion for the fetus, ➡️allow fetal movement, ➡️stabilize the temperature to protect the fetus from extreme temperature changes, and ➡️permit proper lung development.

primary functions of the amniotic fluid -give 4

lecithin-sphingomyelin (L/S) ratio

reference method to which tests of FLM are compared

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respiratory distress occurs in the presence of an L/S ratio of 2.0. Therefore, a thin-layer chromatography lung profile must include lecithin, sphingomyelin, and PG to provide an accurate measurement of FLM.

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specimens must be protected from light at all times. Specimens should be immediately centrifuged to remove particulate interference. Specimens contaminated with meconium will cause falsely low values and are not acceptable for spectrophotometric analysis :-)

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the number of lamellar bodies present in the amniotic fluid correlates with the amount of phospholipid present in the fetal lungs. :-)

Lecithin

the primary component of the surfactants (phospholipids, neutral lipids, and proteins) that make up the alveolar lining and account for alveolar stability.

Protein and glucose

when fetal urine production begins, the con- centrations of creatinine, urea, and uric acid increase whereas ________ and ____________ concentration decrease.

Meconium,

which is usually defined as newborn's first bowel movement, formed in the intestine from fetal intestinal secretions and swallowed amniotic fluid. It is a dark green,