Body fluids—Maternal-fetal Flashcards
functions of amniotic fluid
- Provides protective cushion for fetus
- Allows fetal movement
- Stabilizes fetal temperature exposure
- Permits proper lung development
- Exchanges water and chemicals among the fluid, fetus, and maternal circulation
Thin white waxy coating that covers newborn babies’ skin
vernix
sources of amniotic fluid production
fetal urine
lung fluid
maternal circulation
During the first trimester, the approximately —— mL of amniotic fluid is derived primarily from the maternal circulation
35
Increased amniotic fluid peak at ——- mL in the third trimester is the result of fetal urine
800-1200
Lung fluid adds lung ———– to amniotic fluid; used as a measure of lung maturity
surfactants
Excess amniotic fluid from failure of fetus to swallow
>1200 mL
polyhydramnios
Decreased amniotic fluid from increased fetal swallowing, urinary tract deformities, and membrane leakage
<800 mL
Oligohydramnios
used for fetal cytogenetic analysis
sloughed fetal cells in amniotic fluid
Presence of CSF in amniotic fluid indicates…
neural tube defects
fetal age estimation
creatinine
<36 weeks = 1.5 to 2.0 mg/dL
>36 weeks = >2.0 mg/dL
Needed to determine premature membrane rupture or accidental puncture of maternal bladder from amniocentesis
find out if fluid is amniotic or maternal urine
distinguish amniotic fluid from maternal urine
Amniotic fluid has <3.5 mg/dL creatinine and <30 mg/dL urea
Values as high as 10 mg/dL for creatinine and 300 mg/dL for urea may be found in urine
fern test
specimen air dries on glass slide; examined microscopically for “fern-like” amniotic fluid crystals
distinguishes amniotic fluid from urine
indications for amniocentesis at 15-18 weeks
- Mother’s age of 35 or older at delivery
- Family history of genetic diseases
- Earlier pregnancy or child with birth defects
- Parent is a carrier of a metabolic disorder
- Elevated maternal serum alpha-fetoprotein
- Abnormal triple marker screening test
- Previous child with a neural tube disorder
- Three or more miscarriages
indications for amniocentesis at 20-42 weeks
- Fetal lung maturity
- Fetal distress
- HDN caused by Rh blood type incompatibility
- Infection
max —- mL amniotic fluid collected
discard…
30
first 2-3 mL
Protect amniotic specimens from light for bilirubin analysis for ——– at all times
HDFN
Deliver ———- amniotic fluid tests on ice; refrigerate or freeze up to 72 hours if needed
FLM
———- amniotic fluid specimens kept at room temperature or 37°C to prolong cell life
cytogenetic
normal amniotic fluid appearance
colorless, with slight to moderate turbidity from cells
dark green, mucus-like material in amniotic fluid
meconium
fetal distress
dark red-brown amniotic fluid
fetal death
measured in amniotic fluid to determine extent of hemolysis taking place in HDFN
unconjugated bilirubin
Bilirubin causes OD rise at its maximum absorbance level of ——– nm; difference between baseline and this peak is the ——–
450
ΔA450
used to evaluate bilirubin in amniotic fluid
Plots ΔA450 against gestational age
Liley graph
Consists of three zones based on hemolytic severity
Liley graph
liley graph zone I
mildly affected fetus
liley graph zone II
requires careful monitoring
liley graph zone III
severely affected fetus, may require induction of labor or intrauterine exchange transfusion
produced by the fetal liver prior to 18 weeks’ gestation
alpha-fetoprotein (AFP)
Increased ——- levels in maternal blood or amniotic fluid indicate possible anencephaly or spinal bifida
AFP
normal AFP values are based on ———– and the lab uses…… to evaluate
gestational age
multiples of the median (MoM)
abnormal AFP
more than 2x MoM
Follow abnormal AFP with —————-; more specific for neural disorders
fluid amniotic acetylcholinesterase (AChE)
most common complication of early delivery
respiratory distress syndrome (lack of lung surfactant)
FLM reference method
lecithin-sphingomyelin ratio (L/S)
the primary component of the lung surfactants
increases at a slow and steady rate until the 35th week of gestation, when there is a noticeable increase, resulting in the stabilization of the fetal lung alveoli
lecithin
increases at a slow rate until around the 26th week where it can level out and eventually decreases around week 32-35
sphingomyelin
L/S ratio is —— prior to week 35 and rises to —— or greater for alveolar stability after week 35
1.6
2.0
preterm delivery is considered safe with an L/S ratio of —— or higher
2.0
method of measuring L/S ratio
thin-layer chromatography
Lung surface lipid detected after 35 weeks gestation
phosphatidyl glycerol (PG)
PG normally parallels lecithin, except in ————– (delayed), so must be included in L/S ratio
diabetics
————– is an immunologic agglutination test for PG that can replace the L/S ratio
Amniostat-FLM
Blood and meconium do not interfere with…
amniostat-FLM
simple bedside test used for FLM
foam stability
Foam stability
Amniotic fluid is mixed with ————, shaken for ————, and allowed to sit undisturbed for ————
95% ethanol
15 seconds
15 minutes
foam test result indicating good FLM
A continuous line of bubbles around the outside edge
alcohol is antifoaming agent; fluid overcomes it
foam stability index indicating FLM
> 47
semiquantitative modification of foam test
0.5 mL amniotic fluid added to increasing amounts of 95% ethanol
storage form of surfactant
lamellar bodies
lamellar bodies enter amniotic fluid at —– weeks
26
The number of lamellar bodies correlates with the…
amount of phospholipid present in the fetal lungs
lamellar body OD of ——- at 650 nm correlates with L/S ratio of 2.0 and the presence of PG
150
lamellar body count can be obtained using the …
platelet channel of automated hematology analyzers
cannot perform ——- count if fluid is contaminated with blood, meconium or mucus
lamellar body
lamellar body count indicating FLM
> 32,000/uL
Detects fetal fibronectin in cervical swabs to assess the risk of preterm labor for individuals
Rapid fFN
Detects if the amniotic fluid membranes have ruptured
Monoclonal
amnisure
Detects if the amniotic fluid membranes have ruptured
Monoclonal and polyclonal
ROM plus+
Preterm delivery is <—- weeks gestation
37
preterm delivery symptoms
uterine contractions, change in discharge, vaginal bleeding, backache, abdominal discomfort, pelvic pressure, and cramping
preeclampsia triad
Hypertension
Proteinuria
Edema
If mother develops ———, the conditions is called eclampsia
convulsions
cause and cure of preeclampsia
diseased placenta
delivery
Detects PAMG-1 protein marker of the amniotic fluid
amnisure
Sample must be tested within 30 minutes of collection
Blood & fecal matter creates false positive
amnisure
Sample must be run within 6 hours of collection
Up to 10% blood is ok
ROM Plus+
Detects…
- Alpha-fetoprotein (AFP)
- Insulin-like growth factor-binding protein-1 (IGFBP-1)
- Placental protein 12 (PP12)
ROM plus+
Positive test without PROM indicates risk for delivery within 48 hours
ROM plus+
Detection of fetal fibronectin in cervicovaginal secretions
rapid FFN
Risk of preterm delivery in 7-14 days from the time of swab if positive
rapid FFN
patient must have intact amniotic membranes and be less than 3 cm dilated to use
rapid FFN
Singleton pregnancy
22-30 weeks + 6 days gestation
isoform of fibronectin and is a complex adhesive glycoprotein
FFN
confined to the extracellular matrix of the region defining the junction of the maternal decidua (uterine lining) and the chorion (fetal sac) within the uterus
FFN
elevated in cervical secretions during the first 24 weeks of a normal pregnancy
Not understood why (growth of the placenta?)
FFN
Detection between 24-34 weeks is associated with preterm delivery in symptomatic and asymptomatic pregnancies
FFN
functional layer of the endometrium of the pregnant mom’s uterus
decidua
