This document discusses fetal heart rate monitoring techniques and patterns. It describes intermittent auscultation using a fetoscope or Doppler ultrasound, and continuous electronic fetal monitoring using cardiotocography. Normal fetal heart rate is between 120-160 bpm; patterns like late decelerations, variable decelerations, or a sinusoidal pattern are non-reassuring. The document outlines how to interpret and manage different fetal heart rate patterns.
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FHR monitoring in real sense is fetal brain monitoring because
fetal brain responds to hypoxia by altering FHR.
Methods of fetal heart rate monitoring styles .
Intermittent auscultation
Fetoscope.
Doppler US device.
Continuous electrical FHR monitoring (EFM).
Cardiotocography (CTG).
FHRM…
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Intermittent auscultation
Advantages
widely available, easy inexpensive.
Effective if done in consistent manner at appropriate
interval for the stage of labor.
Limitation
Sometimes difficult in obesity & polyhydramnios .
Can’t detect early fetal heart beat abnormality.
FHRM…
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Advantages of EFM over clinical monitoring.
Can detect hypoxia early and can explain the mechanism of
hypoxia and its specific treatment.
It is an important record for medico legal purpose.
FHRM…
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Drawbacks:
Due to error of interpretation C/S rate may be high.
Instruments are expensive and trained personnel are required to
interpret a trace.
Mother has to be confined in bed.
FHRM…
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Indications for electronic fetal monitoring
Previous history of stillbirth.
Induction of Labor.
Preterm labor.
Non- reassuring fetal status; decreased fetal mov’t
Meconium staining of amniotic fluid.
FHRM…
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Base line rate.
Average fetal heart rate of a ten minutes recording.
Draw a horizontal line by excluding acceleration and deceleration.
Normal = 120 to 160 bpm
Bradycardia <120 bpm
Tachycardia >160 bpm
FHRM…
9. Periodic changes…
Acceleration
An abrupt increase in the FHR above the baseline. Before 32
weeks of gestation, accelerations should last 10 sec and peak 10
bpm above baseline.
After of 32 weeks gestation, accelerations should last 15 sec and
peak 15 bpm above baseline.
A prolonged acceleration is lasting 2 minutes above the base
line but less than 10 minutes.
An acceleration of 10 minutes or more is considered a change in
baseline.
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Periodic changes…
11. Periodic changes…
Except those associated with variable deceleration, accelerations are
physiologic response to fetal movement.
Presence of acceleration –reassuring.
Absence of acceleration-fetus is not moving (doesn’t necessarily mean
hypoxia).
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Periodic changes…
12. Deceleration; Four principal type based on timing, relationships to
contractions, duration and shape.
Early deceleration
Gradual decrease in FHR and return to base line associated with
a uterine contraction.
The onset, nadir and recovery of decelerations are coincident
with the beginning , peak and ending of contraction
respectively.
Caused by compression of fetal head by the uterine cervix (it
stimulates vagal nerve).
Not associated with fetal hypoxia, acidemia or low APGAR
scores.
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Periodic changes…
13. Late deceleration
Gradual decrease and return to baseline FHR associated with
uterine contraction.
The onset of deceleration occur at or after the pick of uterine
contraction and returning to baseline only after the
contraction has ended.
Causes
• Excessive Ux contraction (oxytocin).
• Feto-placental insufficiency .
• Maternal hypotension (epidural ).
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Periodic changes…
14. Variable deceleration
Abrupt decrease in FHR below the base line, onset, depth and
duration have no relation with contractions.
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Periodic changes…
17. • Prolonged deceleration
Decrease in FHR below the baseline ≥15bpm, lasting ≥2min
but <10min from the onset to return to baseline.
May be caused by any of the mechanisms mentioned so far,
but are of a profound and sustained nature.
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Periodic changes…
19. Sinusoid pattern…
Criteria for identifying sinusoidal FHR pattern
A stable baseline FHR of 120-160bpm with regular sine
wave-like oscillations.
An amplitude of 5-15bpm.
Oscillation of sine wave above and below the baseline
and absence of accelerations.
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Periodic changes…
21. Interpretation of FHR patterns
The FHR pattern recorded by an electronic FHR monitor is typically
interpreted as Reassuring FHRP or Non reassuring FHRP.
Reassuring fetal heart rate pattern includes
A baseline fetal heart rate of 120 to 160 bpm.
Absence of late or variable FHR decelerations .
Moderate FHR variability (6 to 25 bpm).
Early decelerations may or may not be present.
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Periodic changes…
22. Interpretation of FHR patterns…
Nonreassuring FHRP
Replaces the term fetal distress.
Non reassuring FHRP includes
Late decelerations (>50% of contraction).
Variable deceleration.
Sinusoidal tracing
Prolonged decelerations./recurrent/*
Bradycardia / tachycardia.
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Periodic changes…