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95 Cards in this Set
- Front
- Back
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How is the amniotic sac formed? |
fusion of amniotic and chorionic membranes |
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What does the amniotic sac do? |
brings nutrients to the baby and acts as a cushion, maintains an even temperature |
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How is amniotic fluid made at first? |
transduction across fetal skin- sweat, mucous |
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How is amniotic fluid made in the last 3rd of the pregnancy? |
fetal urine |
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How is the level of amniotic fluid maintained? |
balance between fetal swallowing and fluid production |
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Normal amount of amniotic fluid at birth? |
800 mL |
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Oligofluid/oligohydroamnios |
lower than the normal amount of fluid |
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Critical oligofluid/oligohydroamnios? |
<200 mL |
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Causes of oligofluid/oligohydroamnios? |
baby is taking in too much fluid or premature rupture of a membrane |
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Polyamnios |
Increased amount of amniotic fluid
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Critically high amniotic fluid? |
>2000 mL |
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Causes of high amount of amniotic fluid? |
nervous system or GI disorder, diabetic mother |
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What is used in genetic testing of amniotic fluid? |
hair/skin cells retrieved by amniocentesis |
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How is an amniocentesis done? |
through amniotic sac guided by ultrasound |
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What is a major risk of amnio? |
introducing bacteria, higher risk if you do it transvaginally |
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1 in 100 amniocentesis procedures will result in? |
premature birth or spontaneous abortion |
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At how many weeks are amnio procedures allowed? |
after 14 weeks |
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How much amniotic fluid should be drawn? |
<30 mL |
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Reasons for amnocentesis |
1) genetic disorders 2) previous miscarriages 3) detection of HDN 4) fetal age: usually for lung development |
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How quickly should amniotic fluid be run for analytes? |
30 minutes |
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How should lung development samples be kept? |
on wet ice in the refrigerator because lecithin levels decrease quickly after being drawn |
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How should a bilirubin sample be kept? |
out of the light |
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Normal color of amniotic fluid |
clear to pale yellow |
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How to see if RBC in amniotic fluid are maternal or fetal? |
kleihauer betke stain: fetal cells (HbF) resist acid and stain pink while adult cells look like ghost cells |
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What does dark red/brown in amniotic fluid indicate? |
hemorrhaging- associated with cell death |
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What does green amniotic fluid indicate? |
meconium- baby can suffocate on it |
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When are genetic testings done on amniotic fluid? |
miscarriages, genetic conditions |
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When is Karyotyping done on amniotic fluid? |
do at 20 weeks gestation |
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WHat bilirubin is seen in amniotic fluid for HDN and how? |
seen on a spec- unconjugated |
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Wavelength bilirubin spikes at |
450 nm |
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Lilley zone definition |
direct correlation between gestational age, amount of bilirubin, and likeliness of HDFN |
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3 Lilley zones |
1) no distress 2) hemolytic anemia, may need early delivery 3) high risk of infant death |
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What can interfere with bilirubin measurements? |
oxyhemoglobin (peaks at 410 nm) |
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How do you differentiate a bilirubin an oxyhemoglobin spike? |
spin and remove RBCs |
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Why shouldn't bilirubin be run on a baby older than 1 month? |
carotene is developed and may interfere |
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Does erythropoietin increase or decrease with fetal distress? |
increase |
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Most common neural tube defect? |
spina bifida |
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WHen in spinal cord development done? |
by the 4th week gestation |
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What can happen if neural tube doesnt close properly? |
spina bifida, microencephaly, ancephaly, hydroencephaly |
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How are neural tube defects commonly looked at? |
ultrasound |
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What levels may indicate a neural tube defect? |
increase in alphafetoprotein increase in isoenzyme acetylcholinesterase |
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When is alphafetoprotein made? |
produced in fetal yolk sac, released into circulation vid transduction, normal in pregnant mothers |
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What can effect alphafetoprotein? |
gestational age and health, weight and nutritional status and habits of mother |
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WHat do high and low alphafetoprotein levels indicate? |
high: neural tube defect low: down syndrome |
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WHat enzyme may also be elevated with a spinal tube defect that is normally not seen in measureable amounts? |
isoenzyme acetylcholinesterase |
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WHat sample cant be used to test for isoenzyme acetylcholinesterase? |
hemolyzed |
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What toxins can be released that can effect a baby? |
high BP, diabetic, or other problems may release creatinine, ammonia, urea etc. that can effect the baby |
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Preeclampsia |
uterine wall can tear away from placenta, can be caused by high protein, edema, diabetes |
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Why is it important to test gestational age? |
if the baby is in distress you need to know if the baby is old enough to deliver early |
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How can creatinine measure gestational age? |
increased later in pregnancy, 2 mg/dL associated with a mature infant |
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WHat does urea testing indicate? |
7 mg/dL: normal too high: kidney distress too low: respiratory distress |
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#1 complication with premature birth |
fetal lung maturity |
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Other terms for CRIB death |
respiratory distress syndrome, hyalin membrane disease |
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What makes lung surfactants? |
alveolar cells of the lung |
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Main job of lung surfactants |
make sure lung doesnt collapse at birth |
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3 surfactants that measure fetal lung maturity |
1) lecithin 2) spingomyelin 3) phosphatidyl glycerol |
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What is the L/S ratio and what is normal? |
lecithin:spingomyelin, 2:1 means lungs are mature |
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When does lecithin start to rise quickly? |
35th week gestation |
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Immature L/S ratio |
<1.6:1 |
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When is 2:1 not a mature L/S ratio? |
diabetic mothers, need 3.5-3:1 |
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What else is looked at in addition to L/S ratio? |
presence of phosphatidyl glycerol |
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How were L/S ratios done that isnt done much now? |
thin layer chromatography |
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How do you handle a lecithin sample? |
keep on ice and refrigerated, cant be contaminated with meconium or blood, centrifuge asap and use supernatant |
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What does the foam test do? |
screens for surfactant maturity |
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What specimen cant be used for the foam test? |
meconium or blood contaminated |
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Foam test procedure |
1) mix amniotic fluid w/ 75% ethanol 2) shake vigorously for 15 sec 3) let sit 15 minutes 4) bubbles and foam = enough surfactant |
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What sample is acceptable for phosphatidyl glycerol agglutination? |
meconium and blood WONT interfere! |
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Phosphatidyl glycerol agglutination procedure |
use polyclonal IgG and mix with fluid, agglutination = positive |
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When is phosphatidyl glycerol often delayed? |
diabetic mothers |
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What are lamellar bodies? |
when alveolar cells make surfactants, they are stored in cytoplasmic granules called lamellar bodies |
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What do lamellar bodies indicate? |
the more lamellar bodies in amniotic fluid, the more mature the baby 35,000 /microliter = mature |
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Why is lamellar bodies a good test? |
sensitive, can be done on heme analyzers in platelet counting chamber |
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How does the platelet counting chamber work? |
resistance pulse counting |
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What wont interfere with lamellar body test? |
meconium *blood will! |
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What is fluorescent polarization looking for? |
capture of light |
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In fluorescent polarization, more capture of light = |
increased polarization |
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What happens when tracer molecules are unbound? |
they spin and scatter light, decreasing polarization |
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Why is fluorescent polarization competitive? |
tracer competes with analyte for binding site |
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If there are less tracers than analytes... |
tracers will be unbound and will scatter light and decrease polarization |
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If there are less analytes than tracers... |
tracers will bind and capture more light, increasing polarization |
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How does an increase in surfactant effect viscosity? |
decreased viscosity |
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What is measured in fluorescent polarization for surfactants? |
albumin vs. lecithin |
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Albumin vs lecithin levels in pregnancy |
albumin stays similar, lecithin increases quickly at 35 weeks |
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How does the albumin lecithin FP work? |
add a tracer molecule with fluorescent dye to bind to albumin or lecithin, albumin and lecithin compete to bind to tracer molecule |
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If albumin lecithin polarization is increased, how does the tracer move and which is more abundant? |
slowly because of the weight of albumin, so albumin is increased |
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If albumin lecithin polarization in decreased, how is the tracer moving and which is more abundant? |
quickly because lecithin is lighter, so lecithin is increased |
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Is a decreased or increased polarization indicative of maturity? |
decreased, more lecithin |
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WHat sample is not acceptable for lecithin albumin FP? |
meconium or blood, centrifuged |
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Why isnt albumin lecithin FP done much? |
phosphatidyl glycerol agglutination |
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What is fibrinolectin? |
glycoproteins that crosslinkk cells together by binding collagen |
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Where is fibrinolectin found? |
cell surfaces, plasma, amniotic fluid |
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When are fetal fibrinolectins made? |
pregnancy |
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When is FDC-6 , fetal fibrinolectin detected? |
not detected until right before birth |
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Where is fetalfibrinolectin sampled from? |
cervical, vaginal fluid |
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What value of fetal fibrinolectin indicates preterm delivery? |
>50 ng/mL do 3 times to make sure it isnt false labor |
