Antepartum fetal monitoring

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09.04.2015 1 ANTEPARTUM FETAL ANTEPARTUM FETAL MONITORING MONITORING Tevfik Yoldemir MD, BBA Marmara University Department of Obstetrics and Gynecology Division of Reproductive Endocrinology and Infertility ANTEPARTUM FETAL MONITORING ANTEPARTUM FETAL MONITORING Two thirds of fetal deaths Two thirds of fetal deaths occur before the occur before the onset of labor. onset of labor. Many Many antepartum antepartum deaths occur in women deaths occur in women at risk for at risk for uteroplacental uteroplacental insufficiency. insufficiency. Ideal test: allows intervention before fetal Ideal test: allows intervention before fetal death or damage from asphyxia. death or damage from asphyxia. Preferable: treat disease process and Preferable: treat disease process and allow fetus to go to term. allow fetus to go to term. ANTEPARTUM FETAL MONITORING ANTEPARTUM FETAL MONITORING Methods for Methods for antepartum antepartum fetal assessment fetal assessment – Fetal movement counting Fetal movement counting – Assessment of uterine growth Assessment of uterine growth – Antepartum Antepartum fetal heart rate testing fetal heart rate testing – Biophysical profile Biophysical profile – Doppler Doppler velocimetry velocimetry ANTEPARTUM FETAL MONITORING ANTEPARTUM FETAL MONITORING Uteroplacental insufficiency Uteroplacental insufficiency – Inadequate delivery of nutritive or respiratory Inadequate delivery of nutritive or respiratory substances to appropriate fetal tissues. substances to appropriate fetal tissues. – Inadequate exchange within the placenta due Inadequate exchange within the placenta due to decreased blood flow, decreased surface to decreased blood flow, decreased surface area or increased membrane thickness. area or increased membrane thickness. – Inadequate maternal delivery of nutrients or Inadequate maternal delivery of nutrients or oxygen to the placenta or to problems of oxygen to the placenta or to problems of inadequate fetal uptake. inadequate fetal uptake. ANTEPARTUM FETAL MONITORING ANTEPARTUM FETAL MONITORING Theoretical scheme of fetal deterioration Theoretical scheme of fetal deterioration Fetal well being (Nutritional compromise) Fetal well being (Nutritional compromise) Fetal growth retardation (Marginal placental Fetal growth retardation (Marginal placental respiratory function) respiratory function) – Fetal hypoxia with stress (Decreasing respiratory Fetal hypoxia with stress (Decreasing respiratory function) function) Some residual effects of intermittent hypoxia Some residual effects of intermittent hypoxia (profound respiratory compromise) (profound respiratory compromise) – Asphyxia Asphyxia – Death Death ANTEPARTUM FETAL MONITORING ANTEPARTUM FETAL MONITORING Conditions placing the fetus at risk for UPI Conditions placing the fetus at risk for UPI Preeclampsia, chronic hypertension, Preeclampsia, chronic hypertension, – Collagen vascular disease, diabetes mellitus, renal Collagen vascular disease, diabetes mellitus, renal disease, disease, Fetal or maternal anemia, blood group sensitization, Fetal or maternal anemia, blood group sensitization, Hyperthyroidism, thrombophilia, cyanotic heart Hyperthyroidism, thrombophilia, cyanotic heart disease, disease, Postdate pregnancy, Postdate pregnancy, Fetal growth restriction Fetal growth restriction

Transcript of Antepartum fetal monitoring

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ANTEPARTUM FETAL ANTEPARTUM FETAL MONITORINGMONITORING

Tevfik Yoldemir MD, BBA

Marmara UniversityDepartment of Obstetrics and Gynecology

Division of Reproductive Endocrinology and Infertility

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Two thirds of fetal deaths Two thirds of fetal deaths occur before the occur before the onset of labor.onset of labor.

•• Many Many antepartumantepartum deaths occur in women deaths occur in women at risk for at risk for uteroplacentaluteroplacental insufficiency.insufficiency.

•• Ideal test: allows intervention before fetal Ideal test: allows intervention before fetal death or damage from asphyxia.death or damage from asphyxia.

•• Preferable: treat disease process and Preferable: treat disease process and allow fetus to go to term.allow fetus to go to term.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Methods for Methods for antepartumantepartum fetal assessmentfetal assessment

–– Fetal movement countingFetal movement counting

–– Assessment of uterine growthAssessment of uterine growth

–– AntepartumAntepartum fetal heart rate testingfetal heart rate testing

–– Biophysical profileBiophysical profile

–– Doppler Doppler velocimetryvelocimetry

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Uteroplacental insufficiencyUteroplacental insufficiency–– Inadequate delivery of nutritive or respiratory Inadequate delivery of nutritive or respiratory substances to appropriate fetal tissues.substances to appropriate fetal tissues.

–– Inadequate exchange within the placenta due Inadequate exchange within the placenta due to decreased blood flow, decreased surface to decreased blood flow, decreased surface area or increased membrane thickness.area or increased membrane thickness.

–– Inadequate maternal delivery of nutrients or Inadequate maternal delivery of nutrients or oxygen to the placenta or to problems of oxygen to the placenta or to problems of inadequate fetal uptake.inadequate fetal uptake.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

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

–– Fetal growth retardation (Marginal placental Fetal growth retardation (Marginal placental respiratory function)respiratory function)

–– Fetal hypoxia with stress (Decreasing respiratory Fetal hypoxia with stress (Decreasing respiratory function)function)

–– Some residual effects of intermittent hypoxia Some residual effects of intermittent hypoxia (profound respiratory compromise)(profound respiratory compromise)

–– AsphyxiaAsphyxia

–– DeathDeath

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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, renal Collagen vascular disease, diabetes mellitus, renal disease,disease,

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

–– Hyperthyroidism, thrombophilia, cyanotic heart Hyperthyroidism, thrombophilia, cyanotic heart disease,disease,

–– Postdate pregnancy,Postdate pregnancy,

–– Fetal growth restrictionFetal growth restriction

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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Fetal movement countingFetal movement counting

–– Maternal perception of a decrease in fetal Maternal perception of a decrease in fetal

movements may be a sign of impending fetal movements may be a sign of impending fetal death.death.

–– It costs nothing.It costs nothing.

–– In a systematic fashion, especially in low risk In a systematic fashion, especially in low risk populations, may detect unsuspected fetal populations, may detect unsuspected fetal jeopardy.jeopardy.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Fetal movement countingFetal movement counting

–– 3 movements in 30 minutes (Sadovsky).3 movements in 30 minutes (Sadovsky).

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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Assessment of uterine growthAssessment of uterine growth

–– General rule: fundal height in centimeters will equal General 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 further Abnormalities of fundal height should lead to further investigation.investigation.

–– Accuracy: poor?Accuracy: poor?

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• When to begin testingWhen to begin testing

–– Single factors with minimal to moderate Single factors with minimal to moderate

increased risk for increased risk for antepartumantepartum fetal death: fetal death: 32 32 weeksweeks..

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

–– When estimated fetal maturity is sufficient to When estimated fetal maturity is sufficient to expect a reasonable chance of survival should expect a reasonable chance of survival should intervention be necessary.intervention be necessary.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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 biophysical Biophysical profile, modified biophysical

profileprofile

–– Doppler velocimetryDoppler velocimetry

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Nonstress test (NST)Nonstress test (NST)

–– Healthy fetuses display normal oscillations and Healthy 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 with Absence of these patterns was associated with increase in neonatal depression and perinatal increase in neonatal depression and perinatal mortality.mortality.

–– Accelerations of the FHR during stress testing Accelerations 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

•• Nonstress test (NST)Nonstress test (NST)–– Accelerations of the FHR occur with fetal Accelerations of the FHR occur with fetal movement, uterine contractions, or in movement, uterine contractions, or in response to external stimuli.response to external stimuli.

–– FHR accelerations appear to be a reflection of FHR accelerations appear to be a reflection of CNS alertness and activity.CNS alertness and activity.

–– Absence of FHR accelerations seems to depict Absence 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

•• Nonstress test (NST)Nonstress test (NST)

–– The endpoint of the NST is the presence or absence The 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 per Most 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 have A healthy fetus < 32 weeks’ gestation may not have the reactivity or the accelerations that meet the the reactivity or the accelerations that meet the criteria of 15 BPM for 15 seconds.criteria of 15 BPM for 15 seconds.

–– The more remote from term, the more likely that The 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 TraceBaseline variability CTGBaseline variability CTG

Baseline variabilityBaseline variability

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Performing the NSTPerforming the NST

–– External monitors for contraction and FHR External monitors for contraction and FHR

measurement applied.measurement applied.

–– Patient in semiPatient in semi--fowler position or left lateral fowler position or left lateral tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).

–– Fetal movement is recorded.Fetal movement is recorded.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Interpreting the NSTInterpreting the NST

–– Reactive: 2 or more accelerations in 20 Reactive: 2 or more accelerations in 20

minutes.minutes.

•• Accelerations: an increase of at least 15 BPM Accelerations: 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 elicit Fetal sound stimulation may be used to elicit a response.a response.

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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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 a May extend the testing period to 40 minutes or perform a backback--up test.up test.

–– There is no universal agreement on the number of There is no universal agreement on the number of accelerations required to consider the test reactive.accelerations required to consider the test reactive.

–– Reactive/Nonreactive with decelerations: individualize Reactive/Nonreactive with decelerations: individualize managementmanagement

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Contraction stress test (CST)Contraction stress test (CST)–– Uterine contractions producing an intraUterine contractions producing an intra--amniotic amniotic 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--arterial arterial pressure, therefore temporarily halting uterine blood pressure, therefore temporarily halting uterine blood flow.flow.

–– A hypoxic fetus will manifest A hypoxic fetus will manifest late decelerationslate decelerations..–– Late decelerations correlate with stillbirth, IUGR, and Late decelerations correlate with stillbirth, IUGR, and low low ApgarApgar scores.scores.

–– OxytocinOxytocin challenge test (OCT)challenge test (OCT)–– Breast (nipple) stimulationBreast (nipple) stimulation

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• How to perform the CSTHow to perform the CST

–– External monitors for contraction and FHR External monitors for contraction and FHR

measurement applied.measurement applied.

–– Patient in Patient in semisemi--fowler position or left lateral fowler position or left lateral tilt (to minimize supine hypotension).tilt (to minimize supine hypotension).

–– Protocol for Protocol for oxytocinoxytocin infusion or breast infusion or breast stimulation.stimulation.

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

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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Interpretation of the CSTInterpretation of the CST

–– Negative: Negative: no late decelerations no late decelerations and adequate and adequate

FHR recordingFHR recording

–– Positive: Late decelerations present with the Positive: Late decelerations present with the majority of contractions (without excessive majority of contractions (without excessive uterine activity)uterine activity)

–– 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

•• Interpretation of the CSTInterpretation of the CST

–– Suspicious: Late decelerations are present with less Suspicious: Late decelerations are present with less than half of the contractions.than half of the contractions.

–– Hyperstimulation: Decelerations after contractions Hyperstimulation: Decelerations after contractions lasting more than 90 seconds, or with contraction lasting more than 90 seconds, or with contraction frequency greater than every 2 minutes.frequency greater than every 2 minutes.

–– Unsatisfactory: Cannot induce adequate contractions Unsatisfactory: Cannot induce adequate contractions or FHR recording is of poor quality.or FHR recording is of poor quality.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Other patternsOther patterns–– Variable decelerations: consider Variable decelerations: consider oligohydramnios or cord entrapment.oligohydramnios or cord entrapment.

–– Loss of variability and blunting of Loss of variability and blunting of decelerations: ominous sign.decelerations: ominous sign.

–– Sinusoidal pattern: ominous pattern. Fetal Sinusoidal 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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Variable Decelerations

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Management of CSTManagement of CST

–– Negative test: repeated weeklyNegative test: repeated weekly

–– Positive test: acted on according to clinical Positive test: acted on according to clinical conditioncondition

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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• When to shorten the interval between When to shorten the interval between testingtesting

–– Deterioration in diabetic controlDeterioration in diabetic control

–– Worsening hypertensionWorsening hypertension

–– Need to introduce antihypertensive Need to introduce antihypertensive medicationmedication

–– Decreased fetal movementDecreased fetal movement

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Biophysical profile (BPP)Biophysical profile (BPP)–– Described by Manning (1980)Described by Manning (1980)

–– The number of biophysical activities that The number of biophysical activities that could be recorded increased with real time could be recorded increased with real time ultrasound: ultrasound: •• Fetal movement (FM)Fetal movement (FM)

•• Fetal tone (FT)Fetal tone (FT)

•• Fetal breathing movements (FB)Fetal breathing movements (FB)

•• Amniotic fluid volume (AFV)Amniotic fluid volume (AFV)

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Biophysical profile (BPP) Biophysical profile (BPP) –– variablesvariables

–– NST: reactive NST: reactive –– as described earlier.as described earlier.

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

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

–– FT: normal FT: normal -- at least 1 episode of extension of at least 1 episode of extension of extremities or spine with return to flexion.extremities or spine with return to flexion.

–– AFV: normal AFV: normal –– largest pocket of fluid greater than 1 largest pocket of fluid greater than 1 cm in vertical diameter.cm in vertical diameter.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Biophysical profile (BPP)Biophysical profile (BPP)

–– Each variable Each 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 number Accuracy improved by increasing the number

of variables assessed.of variables assessed.

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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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 biophysical Nervous impulses that initiate fetal biophysical activities arise from different anatomic sites activities arise from different anatomic sites within the brain.within the brain.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Biophysical profile (BPP)Biophysical profile (BPP)

–– Activities that become active first in fetal Activities 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.

–– Activities that become active later in gestation Activities that become active later in gestation ((NSTNST,,FBMFBM) will be abolished 1) will be abolished 1stst in cases of in cases of hypoxia and acidosis.hypoxia and acidosis.

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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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 risk being in high risk pregnanciespregnancies

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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• 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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Biophysical profile (BPP)Biophysical profile (BPP)–– When the FHR accelerates, there is virtually When the FHR accelerates, there is virtually always fetal movement (FM)always fetal movement (FM)

–– If the NST is reactive, there is fetal movement If the NST is reactive, there is fetal movement (FM) and tone (FT)(FM) and tone (FT)

–– If the NST is reactive, do not need the If the NST is reactive, do not need the ultrasound parameters of the BPPultrasound parameters of the BPP

–– Only the AFV would add additional Only the AFV would add additional information information

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Modified biophysical profile (BPP)Modified biophysical profile (BPP)

–– A standard NST is combined with an amniotic fluid A 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 the If NST is nonreactive or has decelerations, or if the AFI is AFI is << 5.0 cm, then a BPP is performed.5.0 cm, then a BPP is performed.

–– Negative results are repeated every 3 to 4 days.Negative results are repeated every 3 to 4 days.

–– If the AFI > 5.0 cm, a repeat AFI may be done in one If the AFI > 5.0 cm, a repeat AFI may be done in one week. week.

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ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Primary fetal surveillancePrimary fetal surveillance

–– There have been no adequate prospective There have been no adequate prospective randomized studies comparing the various testing randomized studies comparing the various testing modalities.modalities.

–– The final decision regarding choice of fetal The final decision regarding choice of fetal surveillance test is most often determined by surveillance test is most often determined by institutional preference and experience.institutional preference and experience.

–– All forms of fetal testing are valuable and need to be All forms of fetal testing are valuable and need to be interpreted cautiously with full knowledge of the interpreted cautiously with full knowledge of the specific test limitations.specific test limitations.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Primary fetal surveillancePrimary fetal surveillance–– NST: The most popular method NST: The most popular method

•• Easy to perform, easy to interpret, has fewer Easy to perform, easy to interpret, has fewer equivocal results, has excellent patient and equivocal results, has excellent patient and physician acceptance.physician acceptance.

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

–– BPP: BPP: •• Can identify oligohydramnios and anomalous Can identify oligohydramnios and anomalous babies. babies.

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

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Doppler velocimetry of the umbilical arteriesDoppler velocimetry of the umbilical arteries

–– 40% of combined ventricular output is directed to the 40% of combined ventricular output is directed to the placenta by umbilical arteries.placenta by umbilical arteries.

–– Assessment of umbilical blood flow provides Assessment of umbilical blood flow provides information on blood perfusion of the fetoplacental information on blood perfusion of the fetoplacental unit.unit.

–– Volume of flow increases and vascular impedance Volume of flow increases and vascular impedance decreases with advancing gestational age.decreases with advancing gestational age.

–– Low vascular impedance allows a continuous forward Low vascular impedance allows a continuous forward blood flow throughout the cardiac cycle.blood flow throughout the cardiac cycle.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Doppler velocimetryDoppler velocimetry

–– An increase in the vascular resistance of the An increase in the vascular resistance of the fetoplacental unit leads to a decrease in end diastolic fetoplacental unit leads to a decrease in end diastolic flow velocity or its absence in the flow velocity flow velocity or its absence in the flow velocity waveform.waveform.

–– Abnormal waveforms reflect the presence of a Abnormal waveforms reflect the presence of a structural placental lesion.structural placental lesion.

–– Abnormal Doppler results require specific Abnormal Doppler results require specific management protocols and intensive fetal management protocols and intensive fetal surveillance.surveillance.

ANTEPARTUM FETAL MONITORINGANTEPARTUM FETAL MONITORING

•• Doppler velocimetryDoppler velocimetry

–– A poor indicator of fetal compromise or A poor indicator of fetal compromise or

adaptation to the placental abnormality but adaptation to the placental abnormality but does identify patients at risk for increased does identify patients at risk for increased perinatal mortality.perinatal mortality.

–– Strong association between high systolic to Strong association between high systolic to diastolic ratios and IUGR.diastolic ratios and IUGR.

ThankThank youyou forfor youryour attentionattention..