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ANTEPARTUM FETALANTEPARTUM FETAL
MONITORINGMONITORING
Tevfik Yoldemir MD, BBA
Marmara University
Department of Obstetrics and Gynecology
Division of Reproductive Endocrinology and Infertility
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Two thirds of fetal deathsTwo thirds of fetal deaths occur before theoccur before the
onset of labor.onset of labor.
β’β’ ManyMany antepartumantepartum deaths occur in womendeaths occur in women
at risk forat risk for uteroplacentaluteroplacental insufficiency.insufficiency.
β’β’ Ideal test: allows intervention before fetalIdeal test: allows intervention before fetal
death or damage from asphyxia.death or damage from asphyxia.
β’β’ Preferable: treat disease process andPreferable: treat disease process and
allow fetus to go to term.allow fetus to go to term.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Methods forMethods for antepartumantepartum fetal assessmentfetal assessment
ββ Fetal movement countingFetal movement counting
ββ Assessment of uterine growthAssessment of uterine growth
ββ AntepartumAntepartum fetal heart rate testingfetal heart rate testing
ββ Biophysical profileBiophysical profile
ββ DopplerDoppler velocimetryvelocimetry
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Uteroplacental insufficiencyUteroplacental insufficiency
ββ Inadequate delivery of nutritive or respiratoryInadequate delivery of nutritive or respiratory
substances to appropriate fetal tissues.substances to appropriate fetal tissues.
ββ Inadequate exchange within the placenta dueInadequate exchange within the placenta due
to decreased blood flow, decreased surfaceto decreased blood flow, decreased surface
area or increased membrane thickness.area or increased membrane thickness.
ββ Inadequate maternal delivery of nutrients orInadequate maternal delivery of nutrients or
oxygen to the placenta or to problems ofoxygen to the placenta or to problems of
inadequate fetal uptake.inadequate fetal uptake.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Theoretical scheme of fetal deteriorationTheoretical scheme of fetal deterioration
ββ Fetal well being (Nutritional compromise)Fetal well being (Nutritional compromise)
ββ Fetal growth retardation (Marginal placentalFetal growth retardation (Marginal placental
respiratory function)respiratory function)
ββ Fetal hypoxia with stress (Decreasing respiratoryFetal hypoxia with stress (Decreasing respiratory
function)function)
ββ Some residual effects of intermittent hypoxiaSome residual effects of intermittent hypoxia
(profound respiratory compromise)(profound respiratory compromise)
ββ AsphyxiaAsphyxia
ββ DeathDeath
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Conditions placing the fetus at risk for UPIConditions placing the fetus at risk for UPI
ββ Preeclampsia, chronic hypertension,Preeclampsia, chronic hypertension,
ββ Collagen vascular disease, diabetes mellitus, renalCollagen vascular disease, diabetes mellitus, renal
disease,disease,
ββ Fetal or maternal anemia, blood group sensitization,Fetal or maternal anemia, blood group sensitization,
ββ Hyperthyroidism, thrombophilia, cyanotic heartHyperthyroidism, thrombophilia, cyanotic heart
disease,disease,
ββ Postdate pregnancy,Postdate pregnancy,
ββ Fetal growth restrictionFetal growth restriction
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Fetal movement countingFetal movement counting
ββ Maternal perception of a decrease in fetalMaternal perception of a decrease in fetal
movements may be a sign of impending fetalmovements may be a sign of impending fetal
death.death.
ββ It costs nothing.It costs nothing.
ββ In a systematic fashion, especially in low riskIn a systematic fashion, especially in low risk
populations, may detect unsuspected fetalpopulations, may detect unsuspected fetal
jeopardy.jeopardy.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Fetal movement countingFetal movement counting
ββ 3 movements in 30 minutes (Sadovsky).3 movements in 30 minutes (Sadovsky).
ββ Elapsed time to register 10 fetal movementsElapsed time to register 10 fetal movements
(Moore and Piacquadio).(Moore and Piacquadio).
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Assessment of uterine growthAssessment of uterine growth
ββ General rule: fundal height in centimeters will equalGeneral rule: fundal height in centimeters will equal
the weeks of gestation.the weeks of gestation.
ββ Exceptions: maternal obesity, multiple gestation,Exceptions: maternal obesity, multiple gestation,
polyhydramnios, abnormal fetal lie, oligohydramnios,polyhydramnios, abnormal fetal lie, oligohydramnios,
low fetal station, and fetal growth restriction.low fetal station, and fetal growth restriction.
ββ Abnormalities of fundal height should lead to furtherAbnormalities of fundal height should lead to further
investigation.investigation.
ββ Accuracy: poor?Accuracy: poor?
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ When to begin testingWhen to begin testing
ββ Single factors with minimal to moderateSingle factors with minimal to moderate
increased risk forincreased risk for antepartumantepartum fetal death:fetal death: 3232
weeksweeks..
ββ Highest maternal risk factors: 26 weeks.Highest maternal risk factors: 26 weeks.
ββ When estimated fetal maturity is sufficient toWhen estimated fetal maturity is sufficient to
expect a reasonable chance of survival shouldexpect a reasonable chance of survival should
intervention be necessary.intervention be necessary.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Which test to use?Which test to use?
ββ Contraction stress testContraction stress test
β’β’ Low incidence of unexpected fetal deathLow incidence of unexpected fetal death
β’β’ Increase in time, cost and inconvenienceIncrease in time, cost and inconvenience
ββ Nonstress testNonstress test
ββ Biophysical profile, modified biophysicalBiophysical profile, modified biophysical
profileprofile
ββ Doppler velocimetryDoppler velocimetry
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Nonstress test (NST)Nonstress test (NST)
ββ Healthy fetuses display normal oscillations andHealthy fetuses display normal oscillations and
fluctuations of the baseline FHR (Hammacher, 1966;fluctuations of the baseline FHR (Hammacher, 1966;
Kubli, 1969).Kubli, 1969).
ββ Absence of these patterns was associated withAbsence of these patterns was associated with
increase in neonatal depression and perinatalincrease in neonatal depression and perinatal
mortality.mortality.
ββ Accelerations of the FHR during stress testingAccelerations of the FHR during stress testing
correlated with fetal well being (Trierweiler, 1976).correlated with fetal well being (Trierweiler, 1976).
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Nonstress test (NST)Nonstress test (NST)
ββ Accelerations of the FHR occur with fetalAccelerations of the FHR occur with fetal
movement, uterine contractions, or inmovement, uterine contractions, or in
response to external stimuli.response to external stimuli.
ββ FHR accelerations appear to be a reflection ofFHR accelerations appear to be a reflection of
CNS alertness and activity.CNS alertness and activity.
ββ Absence of FHR accelerations seems to depictAbsence of FHR accelerations seems to depict
CNS depression caused by hypoxia, drugs,CNS depression caused by hypoxia, drugs,
fetal sleep, or congenital anomalies.fetal sleep, or congenital anomalies.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Nonstress test (NST)Nonstress test (NST)
ββ The endpoint of the NST is the presence or absenceThe endpoint of the NST is the presence or absence
of FHR accelerations within a specified period of time.of FHR accelerations within a specified period of time.
ββ Most clinicians use 2 accelerations of 15 beats perMost clinicians use 2 accelerations of 15 beats per
minute (BPM) for 15 seconds in a 20minute (BPM) for 15 seconds in a 20--minute period.minute period.
ββ A healthy fetus < 32 weeksβ gestation may not haveA healthy fetus < 32 weeksβ gestation may not have
the reactivity or the accelerations that meet thethe reactivity or the accelerations that meet the
criteria of 15 BPM for 15 seconds.criteria of 15 BPM for 15 seconds.
ββ The more remote from term, the more likely thatThe more remote from term, the more likely that
nonreactivity will be due to fetal prematurity.nonreactivity will be due to fetal prematurity.
Basic Features of FH TraceBasic Features of FH Trace
Baseline variability CTGBaseline variability CTG
Baseline variabilityBaseline variability
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Performing the NSTPerforming the NST
ββ External monitors for contraction and FHRExternal monitors for contraction and FHR
measurement applied.measurement applied.
ββ Patient in semiPatient in semi--fowler position or left lateralfowler position or left lateral
tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).
ββ Fetal movement is recorded.Fetal movement is recorded.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Interpreting the NSTInterpreting the NST
ββ Reactive: 2 or more accelerations in 20Reactive: 2 or more accelerations in 20
minutes.minutes.
β’β’ Accelerations: an increase of at least 15 BPMAccelerations: an increase of at least 15 BPM
above the baseline lasting at least 15 seconds.above the baseline lasting at least 15 seconds.
ββ Fetal sound stimulation may be used to elicitFetal sound stimulation may be used to elicit
a response.a response.
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Interpreting the NSTInterpreting the NST
ββ Non reactive: Less than 2 accelerations in a 20Non reactive: Less than 2 accelerations in a 20--
minute period.minute period.
β’β’ May extend the testing period to 40 minutes or perform aMay extend the testing period to 40 minutes or perform a
backback--up test.up test.
ββ There is no universal agreement on the number ofThere is no universal agreement on the number of
accelerations required to consider the test reactive.accelerations required to consider the test reactive.
ββ Reactive/Nonreactive with decelerations: individualizeReactive/Nonreactive with decelerations: individualize
managementmanagement
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Nonstress testNonstress test
ββ Perinatal mortality: 6.2/1000Perinatal mortality: 6.2/1000
ββ False positive rate: 50%False positive rate: 50%
ββ False negative rate: 3.2 / 1000False negative rate: 3.2 / 1000
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Contraction stress test (CST)Contraction stress test (CST)
ββ Uterine contractions producing an intraUterine contractions producing an intra--amnioticamniotic
pressure in excess of 30 mm Hg create an intrapressure in excess of 30 mm Hg create an intra--
myometrialmyometrial pressure that exceeds mean intrapressure that exceeds mean intra--arterialarterial
pressure, therefore temporarily halting uterine bloodpressure, therefore temporarily halting uterine blood
flow.flow.
ββ A hypoxic fetus will manifestA hypoxic fetus will manifest late decelerationslate decelerations..
ββ Late decelerations correlate with stillbirth, IUGR, andLate decelerations correlate with stillbirth, IUGR, and
lowlow ApgarApgar scores.scores.
ββ OxytocinOxytocin challenge test (OCT)challenge test (OCT)
ββ Breast (nipple) stimulationBreast (nipple) stimulation
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ How to perform the CSTHow to perform the CST
ββ External monitors for contraction and FHRExternal monitors for contraction and FHR
measurement applied.measurement applied.
ββ Patient inPatient in semisemi--fowler position or left lateralfowler position or left lateral
tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).
ββ Protocol forProtocol for oxytocinoxytocin infusion or breastinfusion or breast
stimulation.stimulation.
ββ Goal:Goal: three contractions in ten minutesthree contractions in ten minutes..
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Interpretation of the CSTInterpretation of the CST
ββ Negative:Negative: no late decelerationsno late decelerations and adequateand adequate
FHR recordingFHR recording
ββ Positive: Late decelerations present with thePositive: Late decelerations present with the
majority of contractions (without excessivemajority of contractions (without excessive
uterine activity)uterine activity)
ββ Equivocal test results: Suspicious,Equivocal test results: Suspicious,
hyperstimulationhyperstimulation, unsatisfactory., unsatisfactory.
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Early Decelerations
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Late Decelerations
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Interpretation of the CSTInterpretation of the CST
ββ Suspicious: Late decelerations are present with lessSuspicious: Late decelerations are present with less
than half of the contractions.than half of the contractions.
ββ Hyperstimulation: Decelerations after contractionsHyperstimulation: Decelerations after contractions
lasting more than 90 seconds, or with contractionlasting more than 90 seconds, or with contraction
frequency greater than every 2 minutes.frequency greater than every 2 minutes.
ββ Unsatisfactory: Cannot induce adequate contractionsUnsatisfactory: Cannot induce adequate contractions
or FHR recording is of poor quality.or FHR recording is of poor quality.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Other patternsOther patterns
ββ Variable decelerations: considerVariable decelerations: consider
oligohydramnios or cord entrapment.oligohydramnios or cord entrapment.
ββ Loss of variability and blunting ofLoss of variability and blunting of
decelerations: ominous sign.decelerations: ominous sign.
ββ Sinusoidal pattern: ominous pattern. FetalSinusoidal pattern: ominous pattern. Fetal
anemia or fetalanemia or fetal--maternal hemorrhage.maternal hemorrhage.
ββ Nonreactive negative CST: should not occur,Nonreactive negative CST: should not occur,
preexisting CNS abnormality?preexisting CNS abnormality?
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Variable Decelerations
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Management of CSTManagement of CST
ββ Negative test: repeated weeklyNegative test: repeated weekly
ββ Positive test: acted on according to clinicalPositive test: acted on according to clinical
conditioncondition
ββ Equivocal test: repeat test the next dayEquivocal test: repeat test the next day
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ When to shorten the interval betweenWhen to shorten the interval between
testingtesting
ββ Deterioration in diabetic controlDeterioration in diabetic control
ββ Worsening hypertensionWorsening hypertension
ββ Need to introduce antihypertensiveNeed to introduce antihypertensive
medicationmedication
ββ Decreased fetal movementDecreased fetal movement
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Contraindications to CSTContraindications to CST
ββ PROMPROM
ββ Previous classical cesarean deliveryPrevious classical cesarean delivery
ββ Placenta previaPlacenta previa
ββ Incompetent cervixIncompetent cervix
ββ History of premature labor in this pregnancyHistory of premature labor in this pregnancy
ββ Multiple gestationMultiple gestation
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ Described by Manning (1980)Described by Manning (1980)
ββ The number of biophysical activities thatThe number of biophysical activities that
could be recorded increased with real timecould be recorded increased with real time
ultrasound:ultrasound:
β’β’ Fetal movement (FM)Fetal movement (FM)
β’β’ Fetal tone (FT)Fetal tone (FT)
β’β’ Fetal breathing movements (FB)Fetal breathing movements (FB)
β’β’ Amniotic fluid volume (AFV)Amniotic fluid volume (AFV)
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP) ββ variablesvariables
ββ NST: reactiveNST: reactive ββ as described earlier.as described earlier.
ββ FBM: presentFBM: present -- at least 1 episode of at least 30at least 1 episode of at least 30
seconds duration (within a 30 minute period).seconds duration (within a 30 minute period).
ββ FM: presentFM: present -- at least 3 discrete episodes.at least 3 discrete episodes.
ββ FT: normalFT: normal -- at least 1 episode of extension ofat least 1 episode of extension of
extremities or spine with return to flexion.extremities or spine with return to flexion.
ββ AFV: normalAFV: normal ββ largest pocket of fluid greater than 1largest pocket of fluid greater than 1
cm in vertical diameter.cm in vertical diameter.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ Each variableEach variable
β’β’ When normal: 2When normal: 2
β’β’ When abnormal: 0When abnormal: 0
ββ Highest Score: 10, Lowest Score: 0Highest Score: 10, Lowest Score: 0
ββ Accuracy improved by increasing the numberAccuracy improved by increasing the number
of variables assessed.of variables assessed.
ββ Overall false negative rate: 0.6/1000Overall false negative rate: 0.6/1000
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ Acute markers of fetal compromise: NST, FT,Acute markers of fetal compromise: NST, FT,
FBM, FMFBM, FM
ββ Chronic marker of fetal compromise: AFVChronic marker of fetal compromise: AFV
ββ Nervous impulses that initiate fetal biophysicalNervous impulses that initiate fetal biophysical
activities arise from different anatomic sitesactivities arise from different anatomic sites
within the brain.within the brain.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ Activities that become active first in fetalActivities that become active first in fetal
development (development (FTFT,, FMFM) are the last to) are the last to
disappear when asphyxia arrests all activities.disappear when asphyxia arrests all activities.
ββ Activities that become active later in gestationActivities that become active later in gestation
((NSTNST,,FBMFBM) will be abolished 1) will be abolished 1stst in cases ofin cases of
hypoxia and acidosis.hypoxia and acidosis.
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ Fetal tone: 7.5 to 8.5 weeksFetal tone: 7.5 to 8.5 weeks
ββ Fetal movement: 9 weeksFetal movement: 9 weeks
ββ Fetal breathing: 20 to 21 weeksFetal breathing: 20 to 21 weeks
ββ NST: 24 to 28 weeksNST: 24 to 28 weeks
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ When hypoxia and acidosisWhen hypoxia and acidosis
β’β’ Late decelerations appear (CST)Late decelerations appear (CST)
β’β’ Accelerations disappear (CST, NST, BPP)Accelerations disappear (CST, NST, BPP)
β’β’ Fetal breathing stops (BPP)Fetal breathing stops (BPP)
β’β’ Fetal movement ceases (BPP, FMC)Fetal movement ceases (BPP, FMC)
β’β’ Fetal tone absent (BPP)Fetal tone absent (BPP)
ββ Assessment of fetal wellAssessment of fetal well--being in high riskbeing in high risk
pregnanciespregnancies
β’β’ Reduced perinatal mortality rate from 65/1000 to 5/1000Reduced perinatal mortality rate from 65/1000 to 5/1000
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ BPP and perinatal mortality (PNMR)BPP and perinatal mortality (PNMR)
ββ 12,000 pregnancies (Manning, 1985)12,000 pregnancies (Manning, 1985)
ββ BPP Score Corrected PNMRBPP Score Corrected PNMR
β’β’ 88--10 0.610 0.6
β’β’ 6 0.06 0.0
β’β’ 4 22.04 22.0
β’β’ 2 42.62 42.6
β’β’ 0 187.00 187.0
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Biophysical profile (BPP)Biophysical profile (BPP)
ββ When the FHR accelerates, there is virtuallyWhen the FHR accelerates, there is virtually
always fetal movement (FM)always fetal movement (FM)
ββ If the NST is reactive, there is fetal movementIf the NST is reactive, there is fetal movement
(FM) and tone (FT)(FM) and tone (FT)
ββ If the NST is reactive, do not need theIf the NST is reactive, do not need the
ultrasound parameters of the BPPultrasound parameters of the BPP
ββ Only the AFV would add additionalOnly the AFV would add additional
informationinformation
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Modified biophysical profile (BPP)Modified biophysical profile (BPP)
ββ A standard NST is combined with an amniotic fluidA standard NST is combined with an amniotic fluid
index (AFI)index (AFI)
ββ Negative: Reactive NST / AFI > 5.0 cmNegative: Reactive NST / AFI > 5.0 cm
ββ If NST is nonreactive or has decelerations, or if theIf NST is nonreactive or has decelerations, or if the
AFI isAFI is << 5.0 cm, then a BPP is performed.5.0 cm, then a BPP is performed.
ββ Negative results are repeated every 3 to 4 days.Negative results are repeated every 3 to 4 days.
ββ If the AFI > 5.0 cm, a repeat AFI may be done in oneIf the AFI > 5.0 cm, a repeat AFI may be done in one
week.week.
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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Primary fetal surveillancePrimary fetal surveillance
ββ There have been no adequate prospectiveThere have been no adequate prospective
randomized studies comparing the various testingrandomized studies comparing the various testing
modalities.modalities.
ββ The final decision regarding choice of fetalThe final decision regarding choice of fetal
surveillance test is most often determined bysurveillance test is most often determined by
institutional preference and experience.institutional preference and experience.
ββ All forms of fetal testing are valuable and need to beAll forms of fetal testing are valuable and need to be
interpreted cautiously with full knowledge of theinterpreted cautiously with full knowledge of the
specific test limitations.specific test limitations.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Primary fetal surveillancePrimary fetal surveillance
ββ NST: The most popular methodNST: The most popular method
β’β’ Easy to perform, easy to interpret, has fewerEasy to perform, easy to interpret, has fewer
equivocal results, has excellent patient andequivocal results, has excellent patient and
physician acceptance.physician acceptance.
β’β’ BPP as a back up test.BPP as a back up test.
ββ BPP:BPP:
β’β’ Can identify oligohydramnios and anomalousCan identify oligohydramnios and anomalous
babies.babies.
β’β’ Antepartum death rate is less than with the NST.Antepartum death rate is less than with the NST.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Doppler velocimetry of the umbilical arteriesDoppler velocimetry of the umbilical arteries
ββ 40% of combined ventricular output is directed to the40% of combined ventricular output is directed to the
placenta by umbilical arteries.placenta by umbilical arteries.
ββ Assessment of umbilical blood flow providesAssessment of umbilical blood flow provides
information on blood perfusion of the fetoplacentalinformation on blood perfusion of the fetoplacental
unit.unit.
ββ Volume of flow increases and vascular impedanceVolume of flow increases and vascular impedance
decreases with advancing gestational age.decreases with advancing gestational age.
ββ Low vascular impedance allows a continuous forwardLow vascular impedance allows a continuous forward
blood flow throughout the cardiac cycle.blood flow throughout the cardiac cycle.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Doppler velocimetryDoppler velocimetry
ββ An increase in the vascular resistance of theAn increase in the vascular resistance of the
fetoplacental unit leads to a decrease in end diastolicfetoplacental unit leads to a decrease in end diastolic
flow velocity or its absence in the flow velocityflow velocity or its absence in the flow velocity
waveform.waveform.
ββ Abnormal waveforms reflect the presence of aAbnormal waveforms reflect the presence of a
structural placental lesion.structural placental lesion.
ββ Abnormal Doppler results require specificAbnormal Doppler results require specific
management protocols and intensive fetalmanagement protocols and intensive fetal
surveillance.surveillance.
ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING
β’β’ Doppler velocimetryDoppler velocimetry
ββ A poor indicator of fetal compromise orA poor indicator of fetal compromise or
adaptation to the placental abnormality butadaptation to the placental abnormality but
does identify patients at risk for increaseddoes identify patients at risk for increased
perinatal mortality.perinatal mortality.
ββ Strong association between high systolic toStrong association between high systolic to
diastolic ratios and IUGR.diastolic ratios and IUGR.
ThankThank youyou forfor youryour attentionattention..