Diagnostic TestsDiagnostic TestsByBy

Prof. Unn HidleProf. Unn Hidle

Updated Spring 2010Updated Spring 2010

ULTRASOUNDULTRASOUND

UltrasoundUltrasound

DescriptionDescription Outlines and identifies fetal and maternal structures Outlines and identifies fetal and maternal structures

(uses high frequency sound-waves)(uses high frequency sound-waves) Assists to confirm estimated date of deliveryAssists to confirm estimated date of delivery

ImplementationImplementation Previously, the test used to be done with a full Previously, the test used to be done with a full

bladder (drink 6-8 glasses of water pre-test), but with bladder (drink 6-8 glasses of water pre-test), but with high-tech ultrasound, it is usually no longer high-tech ultrasound, it is usually no longer necessarry. necessarry.

Inform the client that the test presents no known Inform the client that the test presents no known risks to client or fetus risks to client or fetus

AMNIOCENTESISAMNIOCENTESIS

DescriptionDescription Aspiration of amniotic fluid done from 14 Aspiration of amniotic fluid done from 14

weeks of pregnancy and on weeks of pregnancy and on Performed to determine genetic disorders Performed to determine genetic disorders

(after AFP), the sex of the fetus, and fetal (after AFP), the sex of the fetus, and fetal lung maturity (L/S ratio - lung maturity (L/S ratio - this is later in this is later in pregnancypregnancy))

RisksRisks Maternal hemorrhageMaternal hemorrhage Infection Infection Rh isoimmunizationRh isoimmunization Abruptio placentaeAbruptio placentae Amniotic fluid emboliAmniotic fluid emboli

ImplementationImplementation

Instruct client to Instruct client to empty bladderempty bladder before before procedureprocedure

Prepare client for ultrasound, which is Prepare client for ultrasound, which is performed to locate the placentaperformed to locate the placenta

Obtain baseline vital signs and FHR, and Obtain baseline vital signs and FHR, and monitor every 15 minutesmonitor every 15 minutes

Position client supinePosition client supine Instruct client that if chills, fever, leakage of Instruct client that if chills, fever, leakage of

fluid at the needle insertion site, decreased fluid at the needle insertion site, decreased fetal movement, or uterine contractions fetal movement, or uterine contractions occur, to notify the physician or health care occur, to notify the physician or health care providerprovider

CHORIONIC CHORIONIC VILLUS SAMPLINGVILLUS SAMPLING

Chorionic Villus Sampling (CVS)Chorionic Villus Sampling (CVS) DescriptionDescription

Aspiration of a small sample of chorionic villus tissue Aspiration of a small sample of chorionic villus tissue at at 8 to 12 weeks' gestation

Test is performed for the purpose of detecting Test is performed for the purpose of detecting genetic abnormalitiesgenetic abnormalities

ImplementationImplementation Usually, the client is instructed to drink water to fill Usually, the client is instructed to drink water to fill

the bladder before the procedure to aid in the the bladder before the procedure to aid in the position of the uterus for catheter insertionposition of the uterus for catheter insertion

Instruct the client to report bleeding, infection, or Instruct the client to report bleeding, infection, or leakage of fluid at insertion site after procedureleakage of fluid at insertion site after procedure

Rh-negative women may be given RhoGAM for risks Rh-negative women may be given RhoGAM for risks related to the procedurerelated to the procedure

Chorionic Villi SamplingChorionic Villi Sampling

FETOSCOPYFETOSCOPY

Endo-vaginal ultrasound used to Endo-vaginal ultrasound used to locate area to insert catheter into locate area to insert catheter into uterus through the maternal uterus through the maternal abdomen for skin and blood abdomen for skin and blood samples:samples: Percutaneous umbilical blood Percutaneous umbilical blood

sampling (PUBS)sampling (PUBS) Fetal blood is used to help Fetal blood is used to help

diagnose conditions such as diagnose conditions such as hemophilia, congenital rubella, hemophilia, congenital rubella, toxoplasmosis, etc.toxoplasmosis, etc.

COMPUTER AXIAL COMPUTER AXIAL TOMOGRAPHYTOMOGRAPHY

(CAT SCAN or CT SCAN)(CAT SCAN or CT SCAN)

NUCLEAR MAGNETIC NUCLEAR MAGNETIC RESONANCE IMAGINGRESONANCE IMAGING

(NMRI)(NMRI)

FETAL FETAL ECHOCARDIAGRAPHYECHOCARDIAGRAPHY

(EFM & IFM)(EFM & IFM)

NON-STRESS TESTNON-STRESS TEST

(NST)(NST)

Non-stress testNon-stress test

DescriptionDescriptionPerformed to assess placental Performed to assess placental function and oxygenationfunction and oxygenation

Determines Determines fetal well-beingEvaluates fetal heart rate (FHR) Evaluates fetal heart rate (FHR) in response to fetal movementin response to fetal movement

ImplementationImplementation External ultrasound transducer and the External ultrasound transducer and the

tocodynamometer (toco) are applied to the tocodynamometer (toco) are applied to the mother and a tracing of at least 20 minutes’ mother and a tracing of at least 20 minutes’ duration is obtained so that the FHR and the duration is obtained so that the FHR and the uterine activity can be observeduterine activity can be observed

Obtain baseline blood pressure and monitor Obtain baseline blood pressure and monitor BP frequentlyBP frequently

Position mother in the left lateral position to Position mother in the left lateral position to avoid vena cava compression (avoid vena cava compression (reality: reality: SUPINE!!!!)SUPINE!!!!)

Ask mother to press a button every time she Ask mother to press a button every time she feels fetal movementfeels fetal movement

The monitor records a mark at each point of The monitor records a mark at each point of fetal movement, which is used as a fetal movement, which is used as a reference point to assess FHR responsereference point to assess FHR response

Interpretation:Interpretation:

Reactive Nonstress TestReactive Nonstress Test (Normal/Positive) (Normal/Positive) Indicates a healthy fetusIndicates a healthy fetus Two or more fetal heart rate accelerations of at least 15 Two or more fetal heart rate accelerations of at least 15

beats per minute, lasting at least 15 seconds from the beats per minute, lasting at least 15 seconds from the beginning of the acceleration to the end in association beginning of the acceleration to the end in association with fetal movement, during a 20-minute periodwith fetal movement, during a 20-minute period

Nonreactive NonstressNonreactive Nonstress Test Test (Abnormal/Negative)(Abnormal/Negative)

No accelerations or accelerations of less than 15 beats No accelerations or accelerations of less than 15 beats per minute or lasting less than 15 seconds in duration per minute or lasting less than 15 seconds in duration for a 40-minute observationfor a 40-minute observation

UnsatisfactoryUnsatisfactory Cannot be interpreted because of the poor quality of the Cannot be interpreted because of the poor quality of the

FHRFHR

OXYTOSIN OXYTOSIN CHALLENGT TESTCHALLENGT TEST

(OCT)(OCT)

(OST)(OST)

DescriptionDescriptionAssesses placental oxygenation and Assesses placental oxygenation and functionfunction

Determines fetal ability to Determines fetal ability to tolerate tolerate laborlabor and determines fetal well- and determines fetal well-beingbeing

Fetus is exposed to the stressor of Fetus is exposed to the stressor of contractions to assess the adequacy contractions to assess the adequacy of of placental perfusion under placental perfusion under simulated labor conditionssimulated labor conditions

Performed if non-stress test is abnormalPerformed if non-stress test is abnormal *** REALITY: VERY RARELY used anymore since it is so risky!

ImplementationImplementation The external fetal monitor is applied to the The external fetal monitor is applied to the

mother and a 20 to 30-minute baseline strip mother and a 20 to 30-minute baseline strip is recordedis recorded

The uterus is stimulated to contract either The uterus is stimulated to contract either by the administration of a dilute dose of by the administration of a dilute dose of oxytocin (Pitocin) or oxytocin (Pitocin) or by having the mother by having the mother use nipple stimulationuse nipple stimulation (very rare!) until 3 (very rare!) until 3 palpable contractions with a duration of 40 palpable contractions with a duration of 40 seconds or more in a 10-minute period have seconds or more in a 10-minute period have been achievedbeen achieved

Frequent maternal BP readings are done and Frequent maternal BP readings are done and the client is monitored closely while the client is monitored closely while increasing doses of oxytocin are givenincreasing doses of oxytocin are given

InterpretationInterpretation Negative Contraction Stress Test (Normal)Negative Contraction Stress Test (Normal)

Represented by no late or variable decelerations of Represented by no late or variable decelerations of the fetal heart ratethe fetal heart rate

Positive Contraction Stress Test (Abnormal)Positive Contraction Stress Test (Abnormal) Represented by late or variable decelerations with Represented by late or variable decelerations with

50% or more of the contractions in the absence of 50% or more of the contractions in the absence of hyperstimulation of the uterushyperstimulation of the uterus

EquivocalEquivocal Contains decelerations, but with less than 50% of the Contains decelerations, but with less than 50% of the

contractions, or the uterine activity shows a contractions, or the uterine activity shows a hyperstimulated uterushyperstimulated uterus

UnsatisfactoryUnsatisfactory Adequate uterine contractions cannot be achieved, or Adequate uterine contractions cannot be achieved, or

the FHR tracing is not of sufficient quality for the FHR tracing is not of sufficient quality for adequate interpretationadequate interpretation

FETAL BIOPHYSICAL FETAL BIOPHYSICAL PROFILEPROFILE

(FBPP OR BPP)(FBPP OR BPP)

Fetal Biophysical ProfileFetal Biophysical Profile

Overall, evaluates fetal statusOverall, evaluates fetal status Assesses Assesses 5 fetal variables::

FHR with activity = reactive NSTFHR with activity = reactive NST Amniotic fluid volume Amniotic fluid volume Fetal tone (flexion and extension of Fetal tone (flexion and extension of

extremities)extremities) Movements of body or limbsMovements of body or limbs Fetal breathing movements Fetal breathing movements

(oxygenation)(oxygenation)

MATERNAL SERUM STUDIESMATERNAL SERUM STUDIES*** Some of these will be discussed in details throughout

the course

TORCHTORCH ALPHA-FETOPROTEIN (AFP)ALPHA-FETOPROTEIN (AFP) ESTRIOL LEVELESTRIOL LEVEL HCGHCG TRIPEL MARKER SCREENINGTRIPEL MARKER SCREENING QUADRUPLE MARKER SCREENQUADRUPLE MARKER SCREEN

TORCHTORCH

T= Toxoplasmosis = Toxoplasmosis O= Other (HIV, HIB, = Other (HIV, HIB,

Variella, parovirus, syphillis, Variella, parovirus, syphillis, etc)etc)

R= Rubella= RubellaC= Cytomegalovirus (CMV)= Cytomegalovirus (CMV)H= Herpes Virus Type II= Herpes Virus Type II

Alpha-Fetoprotein Screening (AFP)Alpha-Fetoprotein Screening (AFP)

DescriptionDescription Assesses the quantity of fetal serum proteins and if Assesses the quantity of fetal serum proteins and if

elevated is associated with open neural tube and elevated is associated with open neural tube and abdominal wall defectsabdominal wall defects

Can detect spina bifida (elevated) and Down’s Can detect spina bifida (elevated) and Down’s syndrome (decreased)syndrome (decreased)

ImplementationImplementation Explain that the level is determined by a single Explain that the level is determined by a single

maternal blood sample drawn at 15 to 18 weeks' maternal blood sample drawn at 15 to 18 weeks' gestationgestation

If the level is elevated and the gestation is less than If the level is elevated and the gestation is less than 18 weeks, a second sample is drawn18 weeks, a second sample is drawn

An ultrasound is performed when the level is elevated An ultrasound is performed when the level is elevated to rule out fetal abnormalities or multiple gestationto rule out fetal abnormalities or multiple gestation

Estriol LevelEstriol Level

Primary estrogen secreted by the Primary estrogen secreted by the placentaplacenta

Measurements are used to assess Measurements are used to assess placental functioning and fetal viabilityplacental functioning and fetal viability

Not a routine testNot a routine test Done @ 28 weeks and Q week thereafterDone @ 28 weeks and Q week thereafter Low levels = fetoplacental deteriorationLow levels = fetoplacental deterioration

Triple-Marker ScreeningTriple-Marker Screening Includes:Includes:

Human Chorionic Gonadotropin (HCG)Human Chorionic Gonadotropin (HCG) Unconjugated estriolUnconjugated estriol MSAFP (Maternal Serum AFP)MSAFP (Maternal Serum AFP)

Screen for chromosomal abnormalitiesScreen for chromosomal abnormalities Increases detection of Trisomy 18 Increases detection of Trisomy 18

(Edward’s syndrome) and Trisomy 21 (Edward’s syndrome) and Trisomy 21 (Down’s syndrome)(Down’s syndrome)

Test is positive if:Test is positive if: Decreased Estriol and MSAFPDecreased Estriol and MSAFP Increased HCGIncreased HCG

Amniocentesis is offered if positiveAmniocentesis is offered if positive

Now, also a Quadruple screenNow, also a Quadruple screen

Fairly new!Fairly new! Combines the triple screen and a test for Combines the triple screen and a test for

the the hormonehormone inhibin inhibin A A, which is produced , which is produced by the fetus and the placenta by the fetus and the placenta

One large study of over 23,000 women One large study of over 23,000 women has reported that the quadruple screen has reported that the quadruple screen detects almost 86% of all Down syndrome detects almost 86% of all Down syndrome cases. Based on this study, the quadruple cases. Based on this study, the quadruple test is more likely to pick up Down test is more likely to pick up Down syndrome and may be less likely to be syndrome and may be less likely to be false-positive than the triple screen false-positive than the triple screen

Summary findings:

AFP: Increased = Neural Tube Deformity Decreased = Down’s syndrome

HcG: Increased = Down’s syndrome Estriol: Decreased = Down’s syndrome Inhibin A: Increased = Down’s syndrome

All findings, including type and amount of elevated or decreased levels, are evaluated to determine the risk for potential outcomes.

Other tests……Other tests……

Kick Test (Fetal Movement Counting)Kick Test (Fetal Movement Counting) DescriptionDescription

Mother lies down on the left side Mother lies down on the left side for 1 hour after meals and counts for 1 hour after meals and counts fetal kicks for 30 minutesfetal kicks for 30 minutes

Instruct client to notify physician Instruct client to notify physician or health care provider if there or health care provider if there are fewer than 5 kicks in 1 hourare fewer than 5 kicks in 1 hour

THE END!!!!THE END!!!!