Flashcards in 12. Lab Testing and Antepartal Fetal Surveillance Deck (83):
Purpose of test: Blood Grouping
To determine blood type and Rh
Purpose of test: Hemoglobin or Hematocrit
To detect anemia. (Often checked several times during pregnancy)
Purpose of test: CBC
Complete Blood Count:
To detect infection, anemia, or cell abnormalities
Purpose of test: Rh Factor and Antibody Screen
To screen for possible maternal-fetal blood incompatibility
Purpose of test: VDRL or RPR
To screen for syphillis
(Venereal Disease Research Laboratory, Rapid Plasma Reagin)
Purpose of test: Rubella Titer
To determine immunity
Purpose of test: Tuberculin Skin Test
To screen for tuberculosis
Purpose of test: Hemoglobin Electrophoresis
To screen for sickle-cell trait (if client is African-American
Purpose of test: Hepatitis B
To detect presence of antigens in Maternal Blood
Purpose of test: HIV screen
Voluntary test encouraged to detect HIV antibodies
Purpose of test: Urinalysis
To detect renal disease or infection
Purpose of test: Papanicolau Test
To screen for cervical neoplasia
Purpose of test: Cervical Culture
To detect group B strep and STDs
Purpose of test: Triple Screen
To screen for fetal anomalies
What three tests comprise a "Triple Screen"
• Maternal serum alpha-fetorotein
• Human Chorionic Gonadotropin
Purpose of test: Maternal Blood Glucose
To screen for gestational diabetes
Test Significance / Course of Action: Blood Grouping
Identifies possible causes of incompatibility with the blood of the fetus that may cause jaundice
Test Significance / Course of Action: Hemoglobin or Hematocrit
Hgb < 11 g/dL or Hct < 33% may indicate a need for iron supplementation
Test Significance / Course of Action: CBC
12,000 mm3 or more white blood cells or decreased platelets require follow-up
Test Significance / Course of Action: Rh Factor and antibody screen
If mother is Rh (-) and Father is Rh (+) or antibodies are present, additional testing and treatment are required.
(If mom is negative, RhoGAM will be given at 26-28 weeks)
Test Significance / Course of Action: VDRL and RPR
Treat if positive; retest at 36 weeks
Test Significance / Course of Action: Rubella Titer
If titer is 1:8 or less, mother is not immune. Immunize post-partum if not immune.
Test Significance / Course of Action: Hemoglobin Electrophoresis
If mother is positive, check partner. Infant is at risk only if both parents are positive.
Test Significance / Course of Action: Hepatitis B
If present, infants should be given hepatitis immune globulin and vaccine soon after birth.
Positive results require retesting, counseling, and treatment to lower infant infection
Test Significance / Course of Action: Urinalysis
Requires further assessment if positive for more than trace:
• Protein (renal damage, preeclampsia, or normal)
• Glucose (diabetes or normal)
• Ketones (Fasting or dehydration)
• Bacteria (Infection)
Test Significance / Course of Action: Pap Test
Treat and refer ib abnormal cells are present
Test Significance / Course of Action: Cervical Culture
• Treat and retest as necessary.
• Treat GBS during labor.
Test Significance / Course of Action: Triple Screen
Abnormal results may indicate Down Syndrome or neural tube defects.
Test Significance / Course of Action: Maternal Blood Glucose
If elevated, a 3-hour glucose tolerance test is recommended.
Test to be done in the 1st trimester
nuchal translucency screening +PAPP-A
When should the MSAFP Triple / Quad Screen be administered?
When should an ultrasound to check fetal anatomy be administered?
What five tests should be done at the 28 week visit?
• Antibody screen
• RPR (Rapid plasma regain)
What four tests should be done at the 36 week visit?
• RPR (Rapid plasma regain)
• GBS vaginal culture
What does MSAFP stand for
Maternal screen for Alpha-Fetoprotein
What is AFP?
Alpha-Fetoprotein: the main protein in fetal plasma
Where is AFP?
• Diffuses from fetal plasma into fetal urine and is excreted into the amniotic fluid.
• Some AFP crosses placental membranes into the maternal circulation. Therefore, AFP can be measured both in maternal serum (MSAFP) and amniotic fluid (AFAPFP)
Abnormal concentrations of AFP -- implications
Associated with serious fetal anomalies, requiring additional testing to determine the reason for the abnormal concentration.
Levels associated with neural tube defects
Elevated AFP indicates NFP
Levels associated with down's syndrome (3)
• Low AFP
• Low Estriol
• Elevated hCG
Recommendations: Abnormal triple screen (3)
• Genetic counseling
TRIPLE SCREEN IS NOT DIAGNOSTIC
Aspiration of amniotic fluid, wihch contains fetal cells
When is an amniocentesis typically performed?
After 14 weeks, in 3rd trimester
Purpose of amniocentesis (3)
DIAGNOSIS of prenatal anomalies
• Genetic disorders / anomalies
• Pulmonary maturity (3rd trimester)
• Fetal hemolytic disease
Indications of amniocentesis (5)
• Maternal age >35
• History of child with chromosomal abnormality
• Family history of chromosomal abnormalities
• Inherited disorders of metabolism
• Abnormal triple screen
Complications involved with an amniocentesis: Prevalence
• Occur in <1% of cases
Complications involved with an amniocentesis: Maternal
Complications involved with an amniocentesis: Fetal (6)
Fetal death secondary to...
• Direct injury from needle
• Leakage of fluid
Chorionic villus sampling: Purpose
• Used to diagnose fetal chromosome or metabolic abnormalities
Chorionic Villus sampling: What can it NOT diagnose?
• Cannot diagnose anomalies for which amniotic fluid is essential (eg open neural tube defects, which require measuring AFP levels)
Chorionic Villus sampling: Method
• Removal of small tissue specimen from fetal portion of the placenta
• Performed transcervically or transabdominally
Chorionic Villus sampling: Benefit
• Allows for early diagnosis and rapid results
Chorionic Villus sampling:When performed
Chorionic Villus sampling: Complications (6)
• Vaginal spotting or bleeding
• Miscarriage (0.3%)
• Rupture of membranes (0.1%)
• Chorioamnioitis (0.5%)
• Maternal-fetal hemorrhage
• Limb deformities
Fetal movement counts (def)
Movements by the fetus, as assessed by the mother: “Kick counts”
Fetal movement counts -- Reason
Fetal movement is associated with fetal condition. Daily evaluation of these movements provides a way for evaluating the fetus.
Fetal movement counts -- Timing
Begins at 28 weeks; recommended daily.
Fetal movement counts-- Advantages (3)
• Convenient for client, encourages participation in care
Fetal movement counts-- Disadvantages (4)
• Fetal resting state normally decreases movements
• Maternal perception of fetal movement varies widely; even in the same woman at different times.
• Time of day may affect movement (less in the morning, greater in evening)
• Maternal use of drugs (sedative drugs, methadone, heroine, cocaine, alcohol, tobacco) may affect fetal activity.
Non-Stress Test: Purpose
To assess fetal well-being:
• Evaluation of fetal response (fetal heart rate) to natural contractile uterine activity or an increase in fetal activity
• Fetus will produce characteristic heart rate patterns in response to fetal movement
What causes a diminished fetal response? (4)
• Fetal sleep cycle
Benefits of Non-Stress Test (2)
• No contraindications
NST: Interpreting Results (3)
• Reactive: Two accelerations in 20 minutes
• Non-reactive: Doesn’t meet criteria for reactive
• Unsatisfactory: Cannot identify baseline (marked variability) or technical problems / poor tracing
Contraction Stress Test: Function (2)
• Identifies the fetus who is compromised, under stress
• Used to identify the jeopardized fetus that was stable at rest, but showed evidence of compromise after stress
Contraction Stress Test: What to identify (3)
o Must identify fetal baseline, moderate variability, and the possible occurrence of spontaneous contractions.
Contraction Stress Test: Methodology
• Uterine contractions are stimulated
• When adequate contractions or hyperstimulation occurs, stimulation is stopped
Contraction Stress Test: What would indicate fetal distress?
o Uterine contraction decreases uterine blood flow and placental perfusion
• If the decrease is sufficient to produce hypoxia in the fetus, a deceleration in FHR will result, beginning at the peak of the contraction and persisting after its conclusion (late deceleration).
Contraction Stress Test: Interpreting Results
• Negative CST: No decelerations with contractions
• Positive CST: Repetitive decelerations with contractions
Contraction Stress Test: How are uterine contractions stimulated? (2)
• Nipple stimulation: Warm cloth applied to both breasts for 10 minutes, then massage the nipples for ten minutes
• Oxytocin: Given IV to stimulate contractions
Contractions lasting more than 90 seconds or five or more contractions in 10 minutes.
Biophysical Profile: Methods (2 components)
• Ultrasound – uses real-time ultrasound that enables monitoring of fetal biophysical responses to stimuli
• External fetal monitoring
What is the fetal response to central hypoxia? (BPP)
Alteration in movement, tone, breathing, HR
Biophysical Profile: Five components measured
• Fetal breathing movements
• Gross body movements
• Fetal tone
• Fetal heart rate
• Amniotic fluid volume
Biophysical Profile: Results (3)
• Normal: 8-10 if AFV is WNL
Indicates CNS if functional, fetus is not hypoxemic
• Equivocal: 6
• Abnormal: <4 with abnormal AFV. Induction indicated.
What tool is used to measure amniotic fluid?
What does the AFI measure?
Depth in cm of amniotic fluid in all four quadrants
AFI: Normal / Abnormal (3)
• Normal range: Between 5cm and 20 cm
• Oligohydraminos: 20cms
Ultrasounds: 2 types
Abdominal ultrasound (2 characteristics)
• More effective after 1st trimester
• Must have a full bladder
Transvaginal ultrasound (2 characteristics)
• Optimal during 1st trimester
• Bladder can be empty
What does a first trimester sonogram indicate? (5)
o Number, size, location of gestational sacs
o Presence or absence of fetal cardiac and body movements
o Uterine abnormalities or adenexal masses
o Estimated gestational age (EGA)
o Presence and location of IUD