FETAL MONITORING
ANTE AND INTRAPARTUM
DR. OSHINOWO
M.B;B.S, FRCOG
OBSTETRICIAN/GYNAECOLOGIST
INTRODUCTION
• The aim of ANC
– Ensure maternal well being
– Ensure Fetal well being
• Identifying risks factors
• Monitoring of certain parameters ie
Weight, BP, Urinalysis, Blood sugar (if
necessary)
ANTEPARTUM
• PHYSICAL
• BIOCHEMICAL
• ELECTRONIC
PHYSICAL
FUNDAL HEIGHT
– SMALL FOR DATE
• OLIGOHYDRAMNIOS
• IUGR
• IUD
– LARGE FOR DATE
• MULTIPLE GESTATION
• POLYHYDRAMNIOS
• FIBROIDS
ULTRASONOGRAPHY
• Comes in 2D, 3D and recently 4D modes
• Demonstrates features like Fetal
anatomy, fetal weight, fetal movement,
placental location, amniotic fluid volume
• Helpful in specialized procedures like
amniocentesis, Chorionic villus sampling,
Biophysical profile, Fetal doppler, Fetal
echocardiogram etc
GROWTH ULTRASOUND
• Performed every 3 to 4 weeks
• Fetus at risk of fetal growth
restrictions secondary to medical
conditions of pregnancy or fetal
abnormalities
FETAL MOVEMENT ASSESSMENT
• Normal: 10 movements/fetal kicks in 12
hours (Cardiff count to ten)
• Decreased fetal movement may
precede fetal death by days
• Mothers should be encouraged to keep
a FKC especially in high risks patients
NON STRESS TEST (NST)
• Assesses fetal movements with FHR
acceleration
• Reactive/Reassuring NST: 2 or more FHR
accelerations at least 15 bpm above the
baseline lasting at least 15 secs in a 20
mins period
• Non reassuring NST may suggest fetal
acidosis
– What to do depends on gestational age
BIOPHYSICAL PROFILE (BPP)
• Composes of 5 components
1. Non stress test (NST)
2. Amniotic Fluid Volume (vertical pocket of 2cm or more)
3. Fetal breathing movements (30 secs or more in 30
mins)
4. Fetal movements (3 or more in 30 mins)
5. Fetal tone (Extension/Flexion of an extremity)
• Each carry a score of 2 points, a total of 8 or 10 is
Normal, 6 is Equivocal, and 4 or less is abnormal
MODIFIED BIOPHYSICAL PROFILE
• Combines Non stress Test + Amniotic Fluid
Index (AFI)
• AFI is measured by dividing the uterus into 4
quadrants and measuring the largest vertical
pocket in each quadrant; the result summed
up in millimeters
• A nonreactive NST + AFI less than 50mm
requires further intervention
CONTRACTION STRESS TEST (CST)
• Rarely used today
• Measures the response of Fetal HR to
contractions
• The test requires 3 contractions in 10 mins
• A positive or Abnormal test results in
decelerations in more than half of the
contractions
• Negative result: no deceleration with the
contractions
• Contraindication : Any case where labour not
allowed
DOPPLER STUDIES
• Assesses multi-vessel evaluation of fetal
status
• Can be used to assess a compromised fetus
i.e growth restriction
• Functions as a diagnostic tool that alerts the
clinician
INTRAPARTUM FETAL MONITORING
Baseline Fetal Heart Rate (FHR)
– Is the mean level of the FHR when this is
stable, excluding accelerations and
decelerations
– It is determined over a time period of 5-10
minutes, expressed as beats per minute
(bpm)
NOTE: Preterm fetuses tend to have values towards
the upper end of the normal range
14
Basic Features of FH Trace
15
Baseline Variability
– Is the minor fluctuation in baseline FHR
– It is assessed by estimating the difference
in bpm between the highest peak and
lowest trough of fluctuation in one minute
segments of the trace
• Uterine activity Normal variability is reassuring Sign that
fetus nervous system is intact
16
Baseline variability CTG
Baseline variability
17
2 types of Variability
Short- Term variability or Beat to Beat
variability
• Is the difference between successive
heartbeats or the moment
Long Term Variability
• Is wider fluctuations
• Over one (1) minute that causes wavy
appearance in the monitor
• Absent - No fluctuation Minimal - 5 bpm or less
Moderate/Normal – 5bpm to 25
18
Accelerations
 Are transient increases in FHR of
15bpm or more above the baseline and
lasting 15 seconds.
 Accelerations in preterm fetuses may
be of lesser amplitude and shorter
duration.
19
Decelerations
 Are transient episodes of decrease of FHR
below the baseline of more than 15 bpm
lasting at least 15 seconds, which are:
 Early, Variable and Delayed
 Time relationships with contraction cycle
may be variable but most commonly occur
simultaneously with contractions.
20
EFM Decelerations
• Decelerationstransient slowing of
FHR below the
baseline level of
more than 15 bpm
and lasting for 15 sec.
Or more.
21
Early Deceleration
Uniform,
repetitive decrease of FHR with
slow onset early in the contraction
and
slow return to baseline by the end of
the contraction
22
Fig 3 Early Decelerations
23
Late decelerations
Uniform, repetitive decreasing of FHR
with, usually,
slow onset mid to end of the contraction
and
nadir more than 20 seconds after the
peak of the contraction and ending after
the contraction
24
Fig 4 Late Decelerations
25
Variable Deceleration
Repetitive or intermittent
decreasing of FHR with rapid onset
and recovery
• Variable onset
26
Fig 5 Variable Decelerations
27
Prolonged Decelerations
 Decrease of FHR below the baseline of more
than 15 bpm for longer than 90 seconds but
less than 5 minutes
 Is pathological when crosses 2 contractions
i.e 3 mins
 Reduction in Oxygen transfer to placenta
 Associated with poor neonatal outcome
28
Fig 6 Prolonged Deceleration
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Prolonged Decelerations
CAUSES
•
•
•
•
Cord prolapse.
Maternal hypertension
Uterine Hypertonia
Followed by a VE or ARM or SROM with High
presenting part
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Normal antenatal CTG trace
 The normal antenatal CTG is associated with a low
probability of fetal compromise and has the
following features:
 Baseline fetal heart rate (FHR) is between 110-160
bpm
 Variability of FHR is between 5-25 bpm
 Decelerations are absent or early
 Accelerations x2 within 20 minutes
31
Non-reassuring CTG trace
Is where any of the following is present:
 The presence of two or more features is
considered abnormal as these may be associated
with fetal compromise and require further action
 Baseline FHR is between 100-109 bpm or between
161-170 bpm
 Variability of FHR is reduced (3-5 bpm for >40
minutes)
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Abnormal CTG trace
The following features are very likely to be associated
with significant fetal compromise and require further
action– Two of the features described in non-reassuring
CTG trace are present, OR
– Baseline FHR is <100 bpm or >170 bpm
– Variability is absent or <3 bpm
– Variability is sinusoidal
– Decelerations are prolonged for >3 minutes / late / have
complicated variables
33
Process Preparation
– Determine indication for fetal monitoring
– Discuss fetal monitoring with the woman and
obtain permission to commence
– Perform abdominal examination to determine lie
and presentation
– Give the woman the opportunity to empty her
bladder
– The woman should be in an upright or lateral
position (not supine)
34
Process Preparation
• Check the accurate date and time has been set on
the CTG machine, and paper speed is set at 1cm per
minute
• CTGs must be labelled with the mother’s name, her
number and date / time of commencement
• Maternal heart rate must be recorded on the CTG at
commencement of the CTG in order to differentiate
between maternal and fetal heart rates
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ASSESSING THE CTG USING DR C M
BRAVADO
• Determine risk if the woman is a high or low obstetric risk. This sets
the background for the interpretation
• C Assess the frequency and quality of Contractions per 10 minutes.
• M Assess fetal Movements, presence of Meconium and Maternal
observations
• Bra Determine Baseline Rate and compare with earlier rate if possible.
• V Assess baseline Variability, is it normal, increased or reduced.
• A Are Accelerations present in response to fetal movements or
contractions
• D If Decelerations are present, what are their characteristics.
• O Give an overall classification for the CTG
•
•
•
Normal
Suspicious
Pathological
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FETAL SCALP BLOOD SAMPLING
• Useful in the presence of a non reassuring CTG
• A scalp blood sample for pH or lactate
determination
• Specificity is high ( A normal value rules out
asphyxia)
• The sensitivity and positive predictive value of
a low scalp pH in identifying a newborn with
Hypoxic-ischaemic encephalopathy is low
FETAL PULSE OXIMETRY
• Measures fetal oxygenation during labour
• It is performed using a sensor placed
transcervically against the fetal cheek
• Normal values btw 35% and 65%
• Metabolic acidosis develops when the value
falls below 30% for at least 10-15 mins
CONCLUSION
• The well being of any pregnancy begins preconception with adequate counselling of
mothers with medical conditions
• Pregnancy monitoring begins early in the
gestation
• Early and frequent prenatal care allows the
care provider to screen the population to
identify pregnancies at risk, afterall
“A NORMAL DELIVERY IS ONE
IN WHICH THE MOTHER AND
THE BABY ARE IN GOOD
CONDITION REGARDLESS OF
THE MODE OF DELIVERY”
THANK YOU FOR LISTENING