Fetal Health assessment

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Fetal Health assessment

• Piyawadee Wuttikonsammakit, M.D.

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Fetal surveillance

• ???????????????????????? ??????????? 2 ????
• ???????????? (antepartum fetal surveillance)
• ???????? (intrapartum fetal surveillance)

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Intrapartum fetal monitoring
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Intrapartum fetal monitoring

• Aims To identify the fetus at elevated risk for
  labor-related hypoxic injury so that clinicians
  can intervene to prevent or lessen that injury

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Factors that may affect fetal oxygenation in
labor
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Factors that may affect fetal oxygenation in
labor
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Fetal surveillance during labor

• Labour Support
• Intermittent Auscultation
• Admission Cardiotocography
• Electronic Fetal Monitoring
• Fetal Stimulation
• Fetal Scalp Blood Sampling
• Umbilicial Cord Blood Gases

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New technologies

• Fetal Pulse Oximetry
• Fetal Electrocardiogram Analysis
• Near-infrared spectroscopy
• Intrapartum Scalp Lactate Testing

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Labor support

• Emotional support (continuous presence,
  reassurance, and praise)
• Comfort measures (touch, massage, warm
  baths/showers, encouraging fluid intake and
  output)
• Advocacy (communicating the womans wishes)
• Provision of information (coping methods, update
  on progress of labor)

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Continuous support for women during childbirth

• 16 trials 13,391 women
• slightly shorter labor
• more likely to have a spontaneous vaginal birth
• less likely to have intrapartum analgesia
• less likely to report dissatisfaction with their
  childbirth experiences
• Conclusion All women should have support
  throughout labor and birth.

Cochrane Database of Systematic Reviews 2007,
Issue 3
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Intermittent auscultation
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Recommendation frequency of auscultation
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Admission cardiotocography

• Labor admission tests EFM vs. IA
• 4 RCTs including more than 13,000 women
• Admission EFM more likely to have
• increase in incidence of caesarean section
  relative risk (RR) 1.2, 95 CI 1.01.44,
  continuous EFM (RR 1.3 95 CI 1.41.48) and
  fetal blood sampling (RR 1.28 95 CI 1.131.45)
• no significant differences in instrumental
  vaginal birth and fetal and neonatal death

Davane D, et al. Cardiotocography versus
intermittent auscultation of fetal heart on
admission to labour ward for assessment of fetal
wellbeing. Cochrane Database Syst Rev 2012 Feb
152CD005122.
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Admission cardiotocography

• ???? ???????? admission cardiotocography
  ????????????????????????????????? (low risk)
  ???????????????????????????????????????
  ??????????????????????????????????????????????????
  ????????????????????????????????????????
  (recommendation grade B)

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Electronic fetal monitoring
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Continuous CTG as a form of EFM for fetal
assessment during labor

• 12 trials were included (over 37,000 women)
• Results compared to IA, continuous EFM showed
• no significant difference in overall perinatal
  death rate (RR 0.85, 95 CI 0.59 to 1.23)
• a halving of neonatal seizures (RR 0.50, 95 CI
  0.31 to 0.80)
• no significant difference in cerebral palsy (RR
  1.74, 95 CI 0.97 to 3.11)
• a significant increase in C/S (RR 1.66, 95 CI
  1.30 to 2.13)
• more likely to have an instrumental vaginal birth
  (RR 1.16, 95 CI 1.01 to 1.32)

Alfirevic Z. Continuous cardiotocography (CTG) as
a form of electronic fetal monitoring (EFM) for
fetal assessment during labour. Cochrane Database
of Systematic Reviews 2006, Issue 3. Art. No.
CD006066
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Conclusion

• Continuous cardiotocography during labor is
  associated with a reduction in neonatal seizures,
  but no significant differences in cerebral palsy,
  infant mortality or other standard measures of
  neonatal well-being.
• However, continuous cardiotocography was
  associated with an increase in C/S and
  instrumental vaginal births

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EFM recommendation

• ???? ?????????????????????????????????????? (low
  risk) ?????????????????????????????????????
  (intermittent auscultation) ????????????? ??????
  continuous EFM ???????????????????????????????????
  ??????????????????????????????????????????????????
  ????????????????? (recommendation grade B)

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EFM recommendation

• 1. EFM is recommended for pregnancies at risk of
  adverse perinatal outcome.
• 2. Normal EFM during the first stage of labor.
  When a normal tracing is identified, it may be
  appropriate to interrupt the EFM for up to 30 min
  to facilitate periods of ambulation, bathing, or
  position change, providing that (1) the
  maternal-fetal condition is stable and (2) if
  oxytocin is being administered, the infusion rate
  is not increased.

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Pregnancy risk ? continuous EFM

• Antepartum risk
• PIH
• GDM
• Obesity
• APH
• Previous C/S
• Twin
• Breech presentation
• Medical disease
• Fetal risk

• Intrapartum risk
• APH
• Prolonged PROM
• Chorioamnionitis
• Epidural block
• Induction/augmentation of labor
• Preterm labor
• Postterm
• Meconium stained ????????????????
• ??????????????????????????????????????????????????
  ???

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Fetal stimulation

• Digital fetal scalp stimulation
• Vibroacoustic stimulation

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Digital scalp stimulation

• An acceleration of 15 bpm amplitude with a
  duration of 15 sec has been shown to have a very
  high NPV (i.e., normal tracing) and very high
  sensitivity with regard to the absence of fetal
  acidosis.
• It has been generally accepted that an
  acceleratory response is associated with a scalp
  pH of greater than 7.20

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Recommendation

• 1. Digital fetal scalp stimulation is recommended
  in response to atypical FHR tracings.
• 2. In the absence of a positive acceleratory
  response with digital fetal scalp stimulation,
• - fetal scalp blood sampling is recommended
  when available.
• - if fetal scalp blood sampling is not
  available, consideration should be given to
  prompt delivery, depending upon the overall
  clinical situation.

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Vibroacoustic stimulation for fetal assessment in
labor in the presence of a nonreassuring FHR

• There are currently no RCTs that address the
  safety and efficacy of vibroacoustic stimulation
  used to assess fetal well-being in labor in the
  presence of a non-reassuring FHR.
• Although vibroacoustic stimulation has been
  proposed as a simple, non-invasive tool for
  assessment of fetal well-being, there is
  insufficient evidence from RCTs on which to base
  recommendations for use of vibroacoustic
  stimulation in the evaluation of fetal well-being
  in labor in the presence of a non-reassuring FHR

East CE. Vibroacoustic stimulation for fetal
assessment in labour in the presence of a
nonreassuring fetal heart rate trace. Cochrane
Database of Systematic Reviews 2005, Issue 2.
Art. No. CD004664.
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Fetal scalp blood sampling

• If the pH is 7.20 or less, delivery is indicated
  because of the risk of fetal acidemia

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Fetal scalp blood sampling
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Recommendation

• Where facilities and expertise exist, fetal
  scalp blood sampling for assessment of fetal
  acidbase status is recommended in women with
  atypical/abnormal fetal heart tracings at
  gestations gt 34 weeks when delivery is not
  imminent, or if digital fetal scalp stimulation
  does not result in an acceleratory fetal heart
  rate response.

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Electronic fetal heart rate monitoring

• NICHHD FHR interpretation guide

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Electronic fetal heart rate monitoring

• External (indirect) monitoring
• Internal (direct) monitoring

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External (indirect) monitoring

• Doppler ultrasound for fetal heart rate
• Tocodynamometer for uterine contractions

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Internal (direct) monitoring

• Direct application of fetal scalp electrode
• Intrauterine catheter for pressure sensor

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The 2008 National Institute of Child Health and
Human Development Workshop
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Uterine contractions

• Frequency every 3- 5 min, averaged over 30 min.
• Duration optimal 30- 60 sec.
• Other factors such as intensity, relaxation time
  between contractions

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Terminology to describe uterine activity

• Normal 5 contractions in 10 min, over 30 min
  window
• Tachysystole 5 contractions in 10 min, over 30
  min window
• Tachysystole presence or absence of associated
  FHR decelerations
• The terms HYPERSTIMULATION/ HYPERCONTRACTILITY
  are not defined and should be abandoned

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Abnormal uterine contractions

• Dysfunctional labor
• - Irregular contractions
• - Low Fq, low duration/ low amplitude
• Contractions threaten fetal well- being
• - Tachysystole, prolonged contractions
• Contractions threaten maternal well- being
• - Extremely high amplitude- ut rupture
• - High, sustained ut tone- abruptio placenta

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FHR tracing
Full description requires

1. Baseline rate
2. Baseline FHR variability
3. Presence of accelerations
4. Periodic or episodic decelerations
5. Changes or trends of FHR patterns overtime

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Definitions of FHR patterns
Baseline FHR

• Mean FHR rounded to increments of 5 beat/min
  during a 10-minute segment excluding
• Periodic of episodic changes
• Periods of marked FHR variability
• Segments of the baseline that differ by gt 25
  beats/min
• In any 10-minute window the minimum baseline
  duration must be at least 2 minutes

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Definitions of FHR patterns
Baseline FHR

• Normal 110-160 beats/min
• Bradycardia lt 110 beats/min
• Tachycardia gt 160 beats/min

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Baseline FHR
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Bradycardia
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Tachycardia
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CAUSES

• Fetal bradycardia
• Severe/ acute fetal hypoxemia
• Fetal arrhythmia
• Drug effect

• Fetal tachycardia
• Mild/chronic fetal hypoxemia
• Maternal fever
• Maternal hyperthyroidism
• Fetal anemia/ heart failure
• Fetal tachyarrhythmia
• Drugs effect
• Chorioamnionitis

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Baseline FHR variability

• Fluctuations in the baseline FHR of 2 cycles per
  minute or greater
• Irregular in amplitude and frequency
• Visually quatitated as the amplitude of the
  peak-to-trough in beats per minute

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Baseline FHR variability
FHR variability Amplitude range (beats/min)
Absent Undetectable
Minimal lt 5
Moderate 6-25
Marked gt 25
Sinusoidal pattern smooth, sine wave-like
pattern of regular frequency and amplitude
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Variability
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Factors decreased FHR variability

• Fetal behavior states inactive/ sleep
• Medications narcotics, analgesics,
  tranquilizers, parasympatholytics
• Abnormal CNS development extreme premature,
  anencephaly, severe hydrocephalus
• Fetal hypoxia/ tachycardia

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Accelerations

• Visually apparent abrupt increase (defined as
  onset of acceleration to peak in lt 30 sec) in FHR
  above the baseline
• gt 15 beats/min above the baseline, duration gt 15
  seconds and lt 2 minutes from the onset to return
  to baseline (GAgt32 wk)
• gt 10 beats/min above the baseline, duration gt 10
  seconds

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Acceleration
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Prolonged acceleration Duration 2-10
min Acceleration Duration gt 10 min
Tachycardia
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FHR deceleration

• Late deceleration
• Early deceleration
• Variable deceleration
• Prolonged deceleration
• Recurrent deceleration occur 50 of uterine
  contractions in 20 min
• Intermittent deceleration occur lt 50 of uterine
  contractions in 20 min

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Late deceleration

• Visually apparent gradual (defined as onset of
  deceleration to nadir gt 30 seconds) decrease and
  return to baseline FHR associated with a uterine
  contraction.
• The nadir of the deceleration occurring after the
  peak of the contraction.
• In most cases the onset, nadir, and recovery of
  the deceleration occur after the beginning, peak,
  and ending of the contraction, respectively.

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Late deceleration
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Early deceleration

• Visually apparent gradual decrease (defined as
  onset of deceleration to nadir gt 30 seconds) and
  return to baseline FHR associated with a uterine
  contraction.
• The nadir of the deceleration occurring at the
  same time as the peak of the contraction.
• In most cases the onset, nadir, and recovery of
  the deceleration are coincident with the
  beginning, peak, and ending of the contraction,
  respectively.

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Early deceleration
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Variable deceleration

• Visually apparent abrupt decrease (defined as
  onset of deceleration to nadir lt 30 seconds) in
  FHR below the baseline.
• The FHR decrease from the baseline is gt 15
  beats/min, lasting gt 15 seconds, and lt 2 minutes
  from onset to return to baseline.
• When variable decelerations are associated with
  uterine contractions, their onset, depth, and
  duration commonly vary with successive uterine
  contractions.

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Variable deceleration
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Variable deceleration

• Typical variable deceleration
• Transient pre and postacceleratory phase)
  shouldering
• ?????????????????
• ?????????????????????????????????????????

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Variable deceleration

• 1 normal shouldering
• 2 overshoot
• 3 loss of shouldering
• 4 loss of variability
• 5 late recovery
• 6 biphasic deceleration

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Variable deceleration
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Prolonged deceleration

• Visually apparent decrease in FHR below the
  baseline.
• The decrease from the baseline is gt 15 beats/min,
  lasting gt 2 minutes, but lt 10 minutes from onset
  to return to baseline.
• Prolonged deceleration of gt 10 minutes is
  bradycardia

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Prolonged deceleration
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Prolonged deceleration
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Other patterns

• Sinusoidal FHR pattern
• Smooth sine wave- like with cycle Fq of 3- 5/min
  persists for 20 min

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Quantification

1. Any deceleration is quantitated by the depth of
   the nadir in beast per minute below the baseline
   (excluding transient spikes or electronic
   artifact). The duration is quantitated in minutes
   and seconds from the beginning to the end of the
   deceleration. Accelerations are quantitated
   similarly.
2. Decelerations are tentatively defined as
   recurrent if they occur with gt 50 of uterine
   contractions in any 20- minute segment.
3. Bradycardia and tachycardia are quantitated by
   the actual FHR in beats per minute, or the
   visually determined range if the FHR is not
   stable at one rate.

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Three-Tier Fetal Heart Rate Interpretation System

• Category I
• Category I fetal heart rate (FHR) tracings
  include all of the following
• Baseline rate 110160 beats per minute (bpm)
• Baseline FHR variability moderate
• Late or variable decelerations absent
• Early decelerations present or absent
• Accelerations present or absent

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Three-Tier Fetal Heart Rate Interpretation System

• Category II
• Category II FHR tracings include all FHR tracings
  not categorized as Category I or Category III.
• Category II tracings may represent an appreciable
  fraction of those encountered in clinical care.

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Category II

• FHR tracings include any of the following
• Baseline rate
• Bradycardia not accompanied by absent baseline
  variability
• Tachycardia
• Baseline FHR variability
• Minimal baseline variability
• Absent baseline variability not accompanied by
  recurrent decelerations
• Marked baseline variability
• Absence of induced accelerations after fetal
  stimulation

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• Periodic or episodic decelerations
• Recurrent variable decelerations accompanied by
  minimal or moderate baseline variability
• Prolonged deceleration 2 minutes but 10 minutes
• Recurrent late decelerations with moderate
  baseline variability
• Variable decelerations with other
  characteristics, such as slow return to baseline,
  overshoots, or shoulders

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Three-Tier Fetal Heart Rate Interpretation System

• Category III
• Category III FHR tracings include either
• Absent baseline FHR variability and any of the
  following
• - Recurrent late decelerations
• - Recurrent variable decelerations
• - Bradycardia
• Sinusoidal pattern

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Category I (normal)

• ??????????????????????????????????
• Continue monitoring

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Category II (indeterminate)

• ????????????????? ???????????????
  ????????????????????? ???????????
  ?????????????????? ?????????????????????
  ???????????????????????????????????? (fetal pH)
  ????????????? acoustic stimulation
  ????????????????????????
• ???????????? oxytocin
• ??????????????????????????????????????????????????
  ????? ???? ???????????????????? ?????????????????

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Category III

• ??????????uteroplacental insufficiency
  ????????????????????????????? (fetal hypoxia)
  ?????????????????????? (acidemia)
• ????????????????? ???????????????
  ????????????????????? ???????????
  ?????????????????? ?????????????????????
  ???????????????????????????????????? (fetal pH)
  ????????????? acoustic stimulation
  ????????????????????????
• ???????????? oxytocin
• ?????????????????????????? ????
  ???????????????????? ?????????????????

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Quiz 1
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Quiz 2
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Quiz 3
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Quiz 4
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Quiz 5
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Quiz 6
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Quiz 7
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Thank you