figueroa - ante part um fetal monitoring

8/8/2019 Figueroa - Ante Part Um Fetal Monitoring

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ANTEPARTUM FETALANTEPARTUM FETAL

MONITORINGMONITORING

Reinaldo Figueroa, MDReinaldo Figueroa, MD

WinthropWinthrop--University HospitalUniversity Hospital


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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

Two thirds of fetal deaths occur before theTwo thirds of fetal deaths occur before theonset of labor.onset of labor.

Many antepartum deaths occur in womenMany antepartum deaths occur in womenat risk for uteroplacental insufficiency.at risk for uteroplacental insufficiency.

Ideal test: allows intervention before fetalIdeal test: allows intervention before fetal

death or damage from asphyxia.death or damage from asphyxia. Preferable: treat disease process andPreferable: treat disease process andallow fetus to go to term.allow fetus to go to term.


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Methods for antepartum fetal assessmentMethods for antepartum fetal assessment Fetal movement countingFetal movement counting

Assessment of uterine growthAssessment of uterine growth

Antepartum fetal heart rate testingAntepartum fetal heart rate testing

Biophysical profileBiophysical profile

Doppler velocimetryDoppler velocimetry


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Uteroplacental insufficiencyUteroplacental insufficiency Inadequate delivery of nutritive or respiratoryInadequate delivery of nutritive or respiratory

substances to appropriate fetal tissues.substances to appropriate fetal tissues. Inadequate exchange within the placenta dueInadequate exchange within the placenta due

to decreased blood flow, decreased surfaceto decreased blood flow, decreased surfacearea or increased membrane thickness.area or increased membrane thickness.

Inadequate maternal delivery of nutrients orInadequate maternal delivery of nutrients oroxygen to the placenta or to problems ofoxygen to the placenta or to problems ofinadequate fetal uptake.inadequate fetal uptake.


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Theoretical scheme of fetal deteriorationTheoretical scheme of fetal deterioration Fetal well being (Nutritional compromise)Fetal well being (Nutritional compromise)

Fetal growth retardation (Marginal placentalFetal growth retardation (Marginal placentalrespiratory function)respiratory function)

Fetal hypoxia with stress (Decreasing respiratoryFetal hypoxia with stress (Decreasing respiratoryfunction)function)

Some residual effects of intermittent hypoxiaSome residual effects of intermittent hypoxia

(profound respiratory compromise)(profound respiratory compromise) AsphyxiaAsphyxia

DeathDeath


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Conditions placing the fetus at risk for UPIConditions placing the fetus at risk for UPI Preeclampsia, chronic hypertension,Preeclampsia, chronic hypertension,

Collagen vascular disease, diabetes mellitus, renalCollagen vascular disease, diabetes mellitus, renaldisease,disease,

Fetal or maternal anemia, blood group sensitization,Fetal or maternal anemia, blood group sensitization,

Hyperthyroidism, thrombophilia, cyanotic heartHyperthyroidism, thrombophilia, cyanotic heart

disease,disease, Postdate pregnancy,Postdate pregnancy,

Fetal growth restrictionFetal growth restriction


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Fetal movement countingFetal movement counting 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 fetaldeath.death.

It costs nothing.It costs nothing.

In a systematic fashion, especially in low riskIn a systematic fashion, especially in low riskpopulations, may detect unsuspected fetalpopulations, may detect unsuspected fetaljeopardy.jeopardy.


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Fetal movement countingFetal movement counting 3 movements in 30 minutes (Sadovsky).3 movements in 30 minutes (Sadovsky).

Elapsed time to register 10 fetal movementsElapsed time to register 10 fetal movements(Moore and Piacquadio).(Moore and Piacquadio).


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Assessment of uterine growthAssessment of uterine growth General rule: fundal height in centimeters will equalGeneral rule: fundal height in centimeters will equal

the weeks of gestation.the weeks of gestation. 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.

Abnormalities of fundal height should lead to furtherAbnormalities of fundal height should lead to furtherinvestigation.investigation.

Accuracy: poor?Accuracy: poor?


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When to begin testingWhen to begin testing Single factors with minimal to moderateSingle factors with minimal to moderate

increased risk for antepartum fetal death: 32increased risk for antepartum fetal death: 32weeks.weeks.

Highest maternal risk factors: 26 weeks.Highest maternal risk factors: 26 weeks.

When estimated fetal maturity is sufficient toWhen estimated fetal maturity is sufficient toexpect a reasonable chance of survival shouldexpect a reasonable chance of survival shouldintervention be necessary.intervention be necessary.


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Which test to use?Which test to use? Contraction stress testContraction stress test

Low incidence of unexpected fetal deathLow incidence of unexpected fetal death Increase in time, cost and inconvenienceIncrease in time, cost and inconvenience

Nonstress testNonstress test

Biophysical profile, modified biophysicalBiophysical profile, modified biophysicalprofileprofile

Doppler velocimetryDoppler velocimetry


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Contraction stress test (CST)Contraction stress test (CST) 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--

myometrial pressure that exceeds mean intramyometrial pressure that exceeds mean intra--arterialarterialpressure, therefore temporarily halting uterine bloodpressure, therefore temporarily halting uterine bloodflow.flow.

A hypoxic fetus will manifest late decelerations.A hypoxic fetus will manifest late decelerations. Late decelerations correlate with stillbirth, IUGR, andLate decelerations correlate with stillbirth, IUGR, and

low Apgar scores.low Apgar scores. Oxytocin challenge test (OCT) (Ray 1972)Oxytocin challenge test (OCT) (Ray 1972) Breast (nipple) stimulationBreast (nipple) stimulation


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How to perform the CSTHow to perform the CST External monitors for contraction and FHRExternal monitors for contraction and FHR

measurement applied.measurement applied. Patient in semiPatient in semi--fowler position or left lateralfowler position or left lateral

tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).

Protocol for oxytocin infusion or breastProtocol for oxytocin infusion or breaststimulation.stimulation.

Goal: three contractions in ten minutes.Goal: three contractions in ten minutes.


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Interpretation of the CSTInterpretation of the CST Negative: no late decelerations and adequateNegative: no late decelerations and adequate

FHR recordingFHR recording Positive: Late decelerations present with thePositive: Late decelerations present with the

majority of contractions (without excessivemajority of contractions (without excessiveuterine activity)uterine activity)

Equivocal test results: Suspicious,Equivocal test results: Suspicious,hyperstimulation, unsatisfactory.hyperstimulation, unsatisfactory.


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Interpretation of the CSTInterpretation of the CST Suspicious: Late decelerations are present with lessSuspicious: Late decelerations are present with less

than half of the contractions.than half of the contractions. Hyperstimulation: Decelerations after contractionsHyperstimulation: Decelerations after contractions

lasting more than 90 seconds, or with contractionlasting more than 90 seconds, or with contractionfrequency greater than every 2 minutes.frequency greater than every 2 minutes.

Unsatisfactory: Cannot induce adequate contractionsUnsatisfactory: Cannot induce adequate contractionsor FHR recording is of poor quality.or FHR recording is of poor quality.


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Other patternsOther patterns Variable decelerations: considerVariable decelerations: consider

oligohydramnios or cord entrapment.oligohydramnios or cord entrapment. Loss of variability and blunting ofLoss of variability and blunting of

decelerations: ominous sign.decelerations: ominous sign.

Sinusoidal pattern: ominous pattern. FetalSinusoidal pattern: ominous pattern. Fetal

anemia or fetalanemia or fetal--maternal hemorrhage.maternal hemorrhage. Nonreactive negative CST: should not occur,Nonreactive negative CST: should not occur,

preexisting CNS abnormality?preexisting CNS abnormality?


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Management of CSTManagement of CST Negative test: repeated weeklyNegative test: repeated weekly

Positive test: acted on according to clinicalPositive test: acted on according to clinicalconditioncondition

Equivocal test: repeat test the next dayEquivocal test: repeat test the next day


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When to shorten the interval betweenWhen to shorten the interval betweentestingtesting

Deterioration in diabetic controlDeterioration in diabetic control

Worsening hypertensionWorsening hypertension

Need to introduce antihypertensiveNeed to introduce antihypertensive

medicationmedication Decreased fetal movementDecreased fetal movement


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Contraindications to CSTContraindications to CST PROMPROM

Previous classical cesarean deliveryPrevious classical cesarean delivery

Placenta previaPlacenta previa

Incompetent cervixIncompetent cervix

History of premature labor in this pregnancyHistory of premature labor in this pregnancy Multiple gestationMultiple gestation


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Contraction stress testContraction stress test Corrected perinatal mortality rate: 1.2 / 1000Corrected perinatal mortality rate: 1.2 / 1000

High equivocal rateHigh equivocal rate

False positive rate: 8 to 57%False positive rate: 8 to 57%

False negative rate: 0.4 / 1000False negative rate: 0.4 / 1000


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Nonstress test (NST)Nonstress test (NST) 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).

Absence of these patterns was associated withAbsence of these patterns was associated withincrease in neonatal depression and perinatalincrease in neonatal depression and perinatalmortality.mortality.

Accelerations of the FHR during stress testingAccelerations of the FHR during stress testingcorrelated with fetal well being (Trierweiler, 1976).correlated with fetal well being (Trierweiler, 1976).


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Nonstress test (NST)Nonstress test (NST) Accelerations of the FHR occur with fetalAccelerations of the FHR occur with fetal

movement, uterine contractions, or inmovement, uterine contractions, or inresponse to external stimuli.response to external stimuli.

FHR accelerations appear to be a reflection ofFHR accelerations appear to be a reflection ofCNS alertness and activity.CNS alertness and activity.

Absence of FHR accelerations seems to depictAbsence of FHR accelerations seems to depictCNS depression caused by hypoxia, drugs,CNS depression caused by hypoxia, drugs,fetal sleep, or congenital anomalies.fetal sleep, or congenital anomalies.


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Nonstress test (NST)Nonstress test (NST) 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. 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.

A healthy fetus < 32 weeks gestation may not haveA healthy fetus < 32 weeks gestation may not havethe reactivity or the accelerations that meet thethe reactivity or the accelerations that meet thecriteria of 15 BPM for 15 seconds.criteria of 15 BPM for 15 seconds.

The more remote from term, the more likely thatThe more remote from term, the more likely thatnonreactivity will be due to fetal prematurity.nonreactivity will be due to fetal prematurity.


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Performing the NSTPerforming the NST External monitors for contraction and FHRExternal monitors for contraction and FHR

measurement applied.measurement applied. Patient in semiPatient in semi--fowler position or left lateralfowler position or left lateral

tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).

Fetal movement is recorded.Fetal movement is recorded.


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Interpreting the NSTInterpreting the NST Reactive: 2 or more accelerations in 20Reactive: 2 or more accelerations in 20

minutes.minutes.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.

Fetal sound stimulation may be used to elicitFetal sound stimulation may be used to elicit

a response.a response.


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Interpreting the NSTInterpreting the NST Non reactive: Less than 2 accelerations in a 20Non reactive: Less than 2 accelerations in a 20--

minute period.minute period. May extend the testing period to 40 minutes or perform aMay extend the testing period to 40 minutes or perform abackback--up test.up test.

There is no universal agreement on the number ofThere is no universal agreement on the number ofaccelerations required to consider the test reactive.accelerations required to consider the test reactive.

Reactive/Nonreactive with decelerations: individualizeReactive/Nonreactive with decelerations: individualizemanagementmanagement


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Nonstress testNonstress test Perinatal mortality: 6.2/1000Perinatal mortality: 6.2/1000

False positive rate: 50%False positive rate: 50%

False negative rate: 3.2 / 1000False negative rate: 3.2 / 1000


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Biophysical profile (BPP)Biophysical profile (BPP) variablesvariables NST: reactiveNST: reactive as described earlier.as described earlier.

FBM: presentFBM: present -- at least 1 episode of at least 30at least 1 episode of at least 30seconds duration (within a 30 minute period).seconds duration (within a 30 minute period).

FM: presentFM: present -- at least 3 discrete episodes.at least 3 discrete episodes.

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. AFV: normalAFV: normal largest pocket of fluid greater than 1largest pocket of fluid greater than 1

cm in vertical diameter.cm in vertical diameter.


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Biophysical profile (BPP)Biophysical profile (BPP) Each variableEach variable

When normal: 2When normal: 2 When abnormal: 0When abnormal: 0

Highest Score: 10, Lowest Score: 0Highest Score: 10, Lowest Score: 0

Accuracy improved by increasing the numberAccuracy improved by increasing the numberof variables assessed.of variables assessed.

Overall false negative rate: 0.6/1000Overall false negative rate: 0.6/1000


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Biophysical profile (BPP)Biophysical profile (BPP) Acute markers of fetal compromise: NST, FT,Acute markers of fetal compromise: NST, FT,

FBM, FMFBM, FM Chronic marker of fetal compromise: AFVChronic marker of fetal compromise: AFV

Nervous impulses that initiate fetal biophysicalNervous impulses that initiate fetal biophysicalactivities arise from different anatomic sitesactivities arise from different anatomic siteswithin the brain.within the brain.


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Biophysical profile (BPP)Biophysical profile (BPP) Fetal tone: 7.5 to 8.5 weeksFetal tone: 7.5 to 8.5 weeks

Fetal movement: 9 weeksFetal movement: 9 weeks

Fetal breathing: 20 to 21 weeksFetal breathing: 20 to 21 weeks

NST: 24 to 28 weeksNST: 24 to 28 weeks


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Biophysical profile (BPP)Biophysical profile (BPP) When hypoxia and acidosisWhen hypoxia and acidosis

Late decelerations appear (CST)Late decelerations appear (CST)Accelerations disappear (CST, NST, BPP)Accelerations disappear (CST, NST, BPP) Fetal breathing stops (BPP)Fetal breathing stops (BPP) Fetal movement ceases (BPP, FMC)Fetal movement ceases (BPP, FMC) Fetal tone absent (BPP)Fetal tone absent (BPP)

Assessment of fetal wellAssessment of fetal well--being in high riskbeing in high riskpregnanciespregnancies

Reduced perinatal mortality rate from 65/1000 to 5/1000Reduced perinatal mortality rate from 65/1000 to 5/1000


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BPP and perinatal mortality (PNMR)BPP and perinatal mortality (PNMR) 12,000 pregnancies (Manning, 1985)12,000 pregnancies (Manning, 1985)

BPP Score Corrected PNMRBPP Score Corrected PNMR 88--10 0.610 0.6 6 0.06 0.0 4 22.04 22.0 2 42.62 42.6 0 187.00 187.0


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BPP and perinatal morbidityBPP and perinatal morbidity Significant inverse linear correlation (Manning,Significant inverse linear correlation (Manning,

1990)1990) Fetal distressFetal distress NICU admissionNICU admission IUGRIUGR

5 min Apgar


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BPP without NSTBPP without NST When the FM, FBM, FT, and AFV were normal (BPPWhen the FM, FBM, FT, and AFV were normal (BPP

8/8), the probability of a nonreactive NST was8/8), the probability of a nonreactive NST was

exceedingly small (Manning, 1987)exceedingly small (Manning, 1987) The addition of NST did not improve prediction ofThe addition of NST did not improve prediction of

outcome.outcome.

BPP corrected PNMR false negative rateBPP corrected PNMR false negative rate

8/8 1.43 / 1000 0.73 / 10008/8 1.43 / 1000 0.73 / 1000 10/10 1.9 / 1000 0.65 / 100010/10 1.9 / 1000 0.65 / 1000

Selective use of NST saves time: only 2.7% patientsSelective use of NST saves time: only 2.7% patientsneed itneed it


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Biophysical profile (BPP)Biophysical profile (BPP) Normal variables are highly predictive of a goodNormal variables are highly predictive of a good

neonatal outcome (Vintzileos, 1983).neonatal outcome (Vintzileos, 1983). Each abnormal variable was associated with a highEach abnormal variable was associated with a high

false positive ratefalse positive rate

Variables Best predictor of Variables Best predictor of

Absence of FM abnormal FHR in labor (80%) Absence of FM abnormal FHR in labor (80%) NR NST meconium (33%)NR NST meconium (33%) Decreased AFV fetal distress (37.5%)Decreased AFV fetal distress (37.5%) Poor FT perinatal death (42.8%)Poor FT perinatal death (42.8%)


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Biophysical profile (BPP)Biophysical profile (BPP) Combinations of variables increase theCombinations of variables increase the

specificity of the testing, and increase thespecificity of the testing, and increase theability to predict the fetus in jeopardyability to predict the fetus in jeopardy(Vintzileos, 1983)(Vintzileos, 1983)

NR NST, BPP 6NR NST, BPP 6--7: fetal distress (20%)7: fetal distress (20%)

NR NST, BPP 4: fetal distress (100%), deaths (0)NR NST, BPP 4: fetal distress (100%), deaths (0) BPP 1BPP 1--3: perinatal deaths (57%)3: perinatal deaths (57%)


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BPP and NST in relation to fetal outcomeBPP and NST in relation to fetal outcome(Vintzileos, 1983)(Vintzileos, 1983)

If reactive NST, then BPPIf reactive NST, then BPP >> 8 in 95% of cases.8 in 95% of cases. If BPP < 5, then no instances of reactive NST.If BPP < 5, then no instances of reactive NST.

If nonreactive NST, then BPPIf nonreactive NST, then BPP >> 8 in 39% of cases.8 in 39% of cases.

All hypoxic fetuses had nonreactive NST and absentAll hypoxic fetuses had nonreactive NST and absent

fetal breathing.fetal breathing. A reactive NST was associated with good outcome inA reactive NST was associated with good outcome in

all cases.all cases.


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Errors associated with the BPPErrors associated with the BPP Management decisions based on the score only.Management decisions based on the score only.

Intervention based on a false positive low scoreIntervention based on a false positive low score

No intervention based on a false negative normal scoreNo intervention based on a false negative normal score

Management based on BPP without consideringManagement based on BPP without consideringoverall clinical findings.overall clinical findings.

Poor timing of testing.Poor timing of testing.

Not including the NST.Not including the NST. Inexperience operators, poor technique, poorInexperience operators, poor technique, poor

equipment.equipment.


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Biophysical profile (BPP)Biophysical profile (BPP) When the FHR accelerates, there is virtuallyWhen the FHR accelerates, there is virtually

always fetal movement (FM)always fetal movement (FM) 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)

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 Only the AFV would add additionalOnly the AFV would add additional

informationinformation


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Modified biophysical profile (BPP)Modified biophysical profile (BPP) A standard NST is combined with an amniotic fluidA standard NST is combined with an amniotic fluid

index (AFI)index (AFI) Negative: Reactive NST / AFI > 5.0 cmNegative: Reactive NST / AFI > 5.0 cm

If NST is nonreactive or has decelerations, or if theIf NST is nonreactive or has decelerations, or if theAFI isAFI is 5.0 cm, a repeat AFI may be done in oneIf the AFI > 5.0 cm, a repeat AFI may be done in oneweek.week.


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Primary fetal surveillancePrimary fetal surveillance There have been no adequate prospectiveThere have been no adequate prospective

randomized studies comparing the various testingrandomized studies comparing the various testingmodalities.modalities.

The final decision regarding choice of fetalThe final decision regarding choice of fetalsurveillance test is most often determined bysurveillance test is most often determined byinstitutional preference and experience.institutional preference and experience.

All forms of fetal testing are valuable and need to beAll forms of fetal testing are valuable and need to beinterpreted cautiously with full knowledge of theinterpreted cautiously with full knowledge of thespecific test limitations.specific test limitations.


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Primary fetal surveillancePrimary fetal surveillance NST: The most popular methodNST: The most popular method

Easy to perform, easy to interpret, has fewerEasy to perform, easy to interpret, has fewerequivocal results, has excellent patient andequivocal results, has excellent patient andphysician acceptance.physician acceptance.

BPP as a back up test.BPP as a back up test.

BPP:BPP: Can identify oligohydramnios and anomalousCan identify oligohydramnios and anomalous

babies.babies.

Antepartum death rate is less than with the NST.Antepartum death rate is less than with the NST.


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Doppler velocimetry of the umbilical arteriesDoppler velocimetry of the umbilical arteries 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. Assessment of umbilical blood flow providesAssessment of umbilical blood flow providesinformation on blood perfusion of the fetoplacentalinformation on blood perfusion of the fetoplacentalunit.unit.

Volume of flow increases and vascular impedanceVolume of flow increases and vascular impedancedecreases with advancing gestational age.decreases with advancing gestational age.

Low vascular impedance allows a continuous forwardLow vascular impedance allows a continuous forwardblood flow throughout the cardiac cycle.blood flow throughout the cardiac cycle.


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Doppler velocimetryDoppler velocimetry A poor indicator of fetal compromise orA poor indicator of fetal compromise or

adaptation to the placental abnormality butadaptation to the placental abnormality butdoes identify patients at risk for increaseddoes identify patients at risk for increasedperinatal mortality.perinatal mortality.

Strong association between high systolic toStrong association between high systolic to

diastolic ratios and IUGR.diastolic ratios and IUGR.


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THANK YOUTHANK YOU

Freeman RK, Garite TJ, Nageotte MP.Freeman RK, Garite TJ, Nageotte MP.Fetal heart rate monitoring. 3Fetal heart rate monitoring. 3rdrd edition,edition,

2003.2003. Manning FA. Fetal medicine: principles andManning FA. Fetal medicine: principles and

practice. 1995.practice. 1995.

Parer JT. Handbook of fetal heart rateParer JT. Handbook of fetal heart ratemonitoring. 2monitoring. 2ndnd edition, 1997.edition, 1997.

figueroa - ante part um fetal monitoring

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