Antepartum Fetal Surveillance: Aboubakr Elnashar

Fetal Neurodevelopment
Function Center Week
Tone cortex/subcortex 7.5-8.5
Movement cortex/nucle 9
Breathing i ventral surface of fourth
ventricle
20-21
Fetal heart
rate
reactivity
posterior hypothalamus/
medulla
24
Aboubakr Elnashar

Patterns of foetal activity
1.Fetal breathing movements
2.Gross body movements
3.Fine motor movements
Aboubakr Elnashar

Fetal behavioral states
(Nijhuis et al, 1982):
• F1: quiescent state (quiet sleep)
• F2: Frequent gross body movements
• F3: Continuous eye movement. This state was disputed (Philia & James, 1990)
• F4: Vigorous body movements & FHR
accelerations
Aboubakr Elnashar

During the last 10 w of pregnancy:
F. breathing movements: 30% of the time
Gross body movements: 10% of the time
At term:
Cycling between activity & quiescence occurs
over a time span of 60 min
Activity is highest in late evening
FHR variation increases during fetal activity
Accelerations are associated with f. body
movements.
Aboubakr Elnashar

Adaptations to hypoxia
 Early
1.Reduced FHR reactivity
2.Absence of breathing movements
 Late:
1. Reduced body movements and tone
2. Reduced liquor (renal hypoperfusion)
Aboubakr Elnashar

The ideal test
1. Quick
2. Easy to perform
3. Interpreted results that are
reproducible.
4. Clearly identify the compromised
fetus at a stage at which intervention
will improve the outcome
5. Not give an abnormal result for a
healthy fetus.
 Unfortunately, this ideal test does not
yet exist!
Aboubakr Elnashar

I. Fetal movements counting (FMC)
II. Fetal heart rate recording
1.CTG
2.Non-Stress Test (NST)
3.Contraction StressTest (CST) or Oxytocin Challenge
Test (OCT)
4.Nipple stimulation test
5.Vibroacoustic stimulation (VAS)
6.Computerized CTG
III. Biophysical Profile (BPP)
IV. Doppler
Aboubakr Elnashar

I. Fetal movements counting
(FMC)
Idea:
Sadovsky and Yaffee (1973)
pre-eclamptic patients
noticed decreased
fetal movement prior to fetal demise.
Aboubakr Elnashar

Women perceive
most movement when lying down
fewer when sitting and
least while standing.
Busy pregnant women: not
concentrating on fetal activity: often
report a misperception of RFM.
Aboubakr Elnashar

important clinical sign:
significant reduction or sudden
change in movement
The fetus may be in a state of
sleep or the mother may be too
busy to focus on fetal activity.
Although fetal movements tend
to plateau at 32 w, there is no
reduction in the frequency of fetal
movements in the late 3rd
trimester.
Aboubakr Elnashar

How to perform?.
1.One to Two Hours Method.
The patient is asked to relax on her left side 30 min
after eating.
The patient should record the time that she starts the
test and note each time the baby kicks.
Normal: 3-5 Kicks within 60 min
Normal: 10 within 60-75 minutes.
Aboubakr Elnashar

2. The Cardiff Count-to-Ten
chart:
 The patient records fetal
movements during the course of
usual daily activity.
 warning signal:
12 hours without at least 10
perceived movements: patient
should be evaluated and should
undergo further testing e.g.
NST.
Aboubakr Elnashar

Advantages:
1. Inexpensive & noninvasive
2. An effective screening measure
{reductions in fetal mortality from
8.7 deaths per 1,000 live births to
2.1 deaths per 1,000 live births}.
Some authorities suggest that all
pregnant patients, regardless of risk
factors, be counseled about formal
assessment of fetal movement.
Aboubakr Elnashar

Disadvantages:
1. US studies:
mother can feel up to 80% of
movements seen on scan
after 36 w, a mother may feel
only 15% of movements.
2. No defined number of
movements that must be felt,
nor is it known over what time
frame the testing should occur.
Aboubakr Elnashar

3. Routine daily FMC followed by appropriate action
when movements are reduced offer no advantage
over informal inquiry about movements during
standard antenatal care & selective use of formal
counting in high risk cases{B}
(RCT of 68000 women).
4. Although the study did not rule out a beneficial
effect of FMC, the policy would have to be used by
1250 women to prevent one perinatal death.
Aboubakr Elnashar

Should fetal movements be counted routinely in a
formal manner?
insufficient evidence to recommend formal fetal
movement counting using specified alarm limits
(NICE)
Women should be advised to be aware of their
baby’s individual pattern of movements.
If they are concerned about a reduction in or
cessation of fetal movements after 28+0w, they
should contact their doctor. and should not wait
until the next day for assessment of fetal wellbeing.
Aboubakr Elnashar

The effect of FMC in high-risk pregnancies is not
known
Prudent
pay careful attention to their fetal movements.
reduction or an alteration in the movements of their
fetus should be offered some form of assessment
of fetal well-being [E].
Aboubakr Elnashar

II. Fetal heart rate recording
1.CTG
2.NST
3.Contraction stress test
4.Nipple stimulation test
5.Acoustic stimulation test
6.Computerized CTG
Aboubakr Elnashar

1. Fetal heart rate tracings (CTG)
METHOD
Simultaneous recordings are performed by two
separate transducers,
one for FHR and
second one for UC
Aboubakr Elnashar

INTERPRETATION
1.Normal/Reassuring
Trace
 Baseline FHR: 110-150
b/m
 Baseline variability: 10-25
b/m
 At least 2 accelerations
(>15 beats for> 15 sec in
20 min)
 No decelerations.
Aboubakr Elnashar

2. Suspicious/Equivocal Trace.
 Baseline FHR: 150-170 b/m or 100-110 b/m
 Reduced baseline variability (5-10 b/m for >40 m)
 Absence of accelerations for >40 m
 Sporadic deceleration of any type.
 absence of
accelerations
 diminished variability
 late decelerations with
weak spontaneous
contractions. Aboubakr Elnashar

Abnormal/Pathological Trace -
 Baseline FHR: <100 b/m or > 170 b/m
 Silent Pattern (<5 b/m) for >40 min
 Sinusoidal pattern (oscillation frequency = 2-5
cycles/min, amplitude of 5-15 b/m) for >40 m
 No accelerations
 No area of normal baseline variability
 Repeated
late,
prolonged (> 1 minute)
severe variable* (>40 b/m) decelerations.
 *decelerations vary in depth, vary in duration and vary in
timing relative to the uterine activity
Aboubakr Elnashar

Tachycardia
 Sinusoidal pattern
 Late deceleration
normal baseline rate at 120
bpm,
absent baseline variability,
no accelerations
late decelerations
Aboubakr Elnashar

 variable fetal heart rate decelerations.
Reassuring shoulders (accelerations) are
obvious before and after each
deceleration.
baseline tachycardia
minimal variability.
Aboubakr Elnashar

MANAGEMENT:
 Normal/Reassuring Trace –
repeat and/or estimate AFI if considered necessary
acc to the clinical situation and indication for
testing.
 Suspicious/Equivocal Trace –
 Continue for up to 60 min {determine the presence
of fetal rest/activity cycles}.
 Further evaluation acc to the cl situation e.g. fetal
acoustic stimulation, AFI, BPP, Doppler blood
velocity waveform.
 Abnormal/Pathological Trace –
 deliver if clinically appropriate.
 Further evaluation/monitoring if not appropriate to
deliver. Aboubakr Elnashar

Advantages:
It is the most commonly
performed antenatal test for
fetal wellbeing.
Quick
Simple to perform
Aboubakr Elnashar

2. The Non-Stress Test (NST)
(Hammacher et al, 1960)
Idea:
• FHR accelerations:
linked closely with fetal movements
{increased sympathetic output}.
• The long term variability:
{balance between sympathetic & parasympathetic
tone}
• The short term variability (baseline or bandwidth
variability)
{parasympathetic tone}.
Aboubakr Elnashar

Steps:
1. left lateral recumbent position.
2. Place and adjust the external
tocodynamometer and US
transducer to obtain the best
possible tracing.
3. Instruct the patient to record f
movements on the monitor
tracing using the event marker.
4. Observe the EFM tracing until
the criteria for a reactive test are
met
(minimum of 20 min and maximum
of 60 min). Aboubakr Elnashar

 In the event of lack of fetal movement, apply
stimulation e.g. fetal acoustic stimulator.
 Record any relevant clinical information on the
EFM tracing e.g.
BP
T
P
loss of contact
changes in maternal position.
Aboubakr Elnashar

Interpretation:
 Reactive:
2 accelerations of FHR in 20 min.
Each acceleration 15 beat & lasts 15 sec.
 Non-reactive:
no accelerations in 40 min.
Aboubakr Elnashar

•Reactive:
increase of FHR to >15 beats/min for
> 15 sec following fetal movements
Reactive
Aboubakr Elnashar

Antenatal maternal glucose administration:
not to reduce non-reactive CTG
(Cochrane , 2001)
Manual fetal manipulation:
not to reduce the incidence of non-reactive CTG.
(Cochrane , 2001)
Aboubakr Elnashar

Disadvantages:
1. Interpretation may be difficult &
poor agreement between experts
in assessing CTG
2. The predictive value of an abnormal
NST for perinatal morbidity &
mortality:<40%
(Devoe et al, 1985)
Aboubakr Elnashar

3. No significant effect on perinatal
outcome
(MA of 13 trials)
Trend towards increased perinatal
mortality (SR of 4 RCT)
(Cochrane library, 2001)
NST should not be relied upon as
the sole means of establishing fetal
well-being {Ia}
Aboubakr Elnashar

3. The Contraction Stress Test (CST) or
Oxytocin Challenge Test (OCT)
1972: First introduced by Ray
1975: Freeman introduced the parameters of
contraction number and frequency to standardize
the test.
Aboubakr Elnashar

Idea:
It is a test of the
uteroplacental unit.
If fetal oxygenation is
marginal at rest, it will
transiently worsen with uterine
contractions: hypoxemia: late
decelerations.
If variable decelerations
were seen, one should
suspect oligohydramnios.
Aboubakr Elnashar

Steps:
Semi-fowlers position.
If the patient is not having spontaneous
contractions, pitocin is begun at 0.5-1.0 mU and
increased /15-20 minutes until 3C/10 min.
Aboubakr Elnashar

Interpretation:
Negative:
no decelerations with the 3 contractions in the
10 minute window.
Positive:
late decelerations with 50% or more of the
contractions.
Suspicious:
intermittent late decelerations or severe
variable deceleration.
Unsatisfactory:
<3 contractions or hyperstimulation.
Aboubakr Elnashar

•Non-reactive NST followed by CST:
mild late decelerations.
Aboubakr Elnashar

CST: negative
Aboubakr Elnashar

1. Negative
No deceleration
2. Positive
transient
decelerations
Aboubakr Elnashar

Relative contraindications:
1. Preterm labor or certain patients at
high risk of preterm labor
2. Preterm membrane rupture
3. History of extensive uterine surgery or
classical cesarean delivery
4. Known placenta previa
Aboubakr Elnashar

The role of this technique
has yet to be established
it has been associated with reports of fetal death
in cases of unrecognized severe fetal compromise
[E].
Aboubakr Elnashar

4. Nipple stimulation test
Intermittent nipple massage has the same goals.
How to perform
The women stimulate one breast, through their
clothes, for 2 min and then to rest for 5 min.
This cycle is repeated as necessary, but is interrupted
whenever contractions began.
Advantages
Hyperstimulation is not more frequent than
previously reported with CST.
Average time: 45 min.
Easy and quick method
Aboubakr Elnashar

Sequence Of Events With Placental
Insufficiency or Hypoxia
1. Positive CST= late deceleration in 50% of UC.
2. Non reactive NST= No HR acceleration
3. Cessation of fetal movement
4. Basal line tachycardia > 160 bpm
5. Basal line bradycardia <110 bpm
Aboubakr Elnashar

5. VIBROACOUSTIC STIMULATION (VAS)
Idea:
Vibroacoustic stimulator wakes a sleeping fetus:
changing its behavioral state.
How to perform:
Artificial larynxes that generate sound pressure levels
of approximately 80 to 100 decibels is applied in two
or three one-second bursts to the maternal abdomen
near the fetal head.
Aboubakr Elnashar

Advantages:
1. Easy, relatively inexpensive way to
shorten testing times and reduce the
false-positive rates for NST &
biophysical profiles.
2. Fetuses that respond to VAS with
an acceleration on NST or a startle
response on FBP: very low rates of
death within one week of the test.
3. Decrease the incidence of non-
reactive CTG and reducing the testing
time (The Cochrane Database of Systematic
Review, 2001)
Aboubakr Elnashar

6. Computerized CTG
• To improve the objectivity of antenatal CTG
• The program unlike conventional CTG, allows
measurement of short term variability (STV).
• STV=variation measured in 3.75 s epochs.
• FHRV: better predictor of fetal compromise than the
acceleration or decelerations.
• Likelihood of metabolic acidaemia or IUFD can be
calculated according to the STV.
Aboubakr Elnashar

Conventional Vs computerized CTG
1.Fewer additional fetal tests
2.Less time in testing.
3.The study was not large enough to
demonstrate any effect on perinatal morbidity
or mortality.
Aboubakr Elnashar

III. The Biophysical Profile (BPP)
First described by Manning in 1980.
Idea:
Sequence of fetal deterioration
1. Late decelerations appear (CST)
2. Accelerations disappear (NST, BPP, CST)
3. Fetal breathing stops (BPP)
4. Fetal movement stops (BPP)
5. Fetal tone absent (BPP)
6. Amniotic fluid decreases {chronic hypoxia: redistribution of
cardiac output away from the kidneys toward the brain}: AFV is
a quick evaluation of long term uteroplacental function as in the
late 2nd and all the 3rd trimester {AF is essentially fetal urine}.
Aboubakr Elnashar

OBSERVATION CRITERIA FOR
PRESENT
CRITERIA FOR
NEGATIVE
Fetal Tone 1 episode of flexion-
extension-flexion in 30
min
No episodes of flexion-
extension-flexion in 30
minutes
Fetal
Movement
3 gross body
movements in30
min
Less than 3 gross body
movements in 30 minutes
Fetal
Breathing
1 episode of
rhythmic breathing
in 30 min
No episodes of rhythmic
breathing in 30 minutes
Amniotic Fluid
Volume
One 2 centimeter pocket
measured in two
perpendicular planes
A pocket measuring
less than 2
centimeters
NST Reactive test Non-reactive test
Two points are given if the observation is present and zero points are given if it is
absent.
Aboubakr Elnashar

Interpretation:
8:
reassuring.
6:
equivocal: repeat within 24 h.
4 or less:
positive test: strongly suggests preparing the
patient for delivery.
Aboubakr Elnashar

Modifications
1. BPP Manning (1990)
NST
AFV
Fetal breathing.
less cumbersome
results are just as predictive.
Aboubakr Elnashar

2. Placental grading
has been incorporated in the BPP to give an
overall score out of 12 rather than 10.
Aboubakr Elnashar

3. The most powerful components:
•AFI: indicator of long term uteroplacental function
•NST: short term indicator of fetal acid-base status.
assessment of fetal well-being using these two
tools alone may well be as effective as formal BPP
Aboubakr Elnashar

 Advantages:
1. In high-risk:
 observational studies: effective
 {good negative predictive value
(99.9%) i.e. fetal death is rare in
women with a normal FBP
 rarely abnormal when Doppler
findings were normal}.
Aboubakr Elnashar

2. In pre-labour rupture of the
membranes
{fetal breathing movements is
reduced in the presence of
chorioamnionitis}
But sensitivity for abnormal BPP in
the presence of chorioamnionitis is
25%[B]: value of BPP is limited
Aboubakr Elnashar

 Disadvantages:
1. Difficult and time-consuming
2. False-positive rate: 70%: increased
rates of unnecessary intervention.
3. Systematic review of five RCTs:
failed to demonstrate any significant
benefit of BPP on pregnancy
outcome when compared to NST
Aboubakr Elnashar

4. In low risk: cannot be recommended
for routine monitoring
5. In high Risk: positive predictive
value of 35% (observational study)
No enough evidence from RCTs
(Cochrane Systematic Review, 2000).: cannot be
recommended for routine monitoring
for primary surveillance in SGA
Aboubakr Elnashar

Statistical Characteristics of Selected
Antepartum Fetal Tests
Characteristic NST CST BPP
Specificity Poor Average High
Specificity High High High
False-positive rate High High High
False-negative rate Low Low Average
Aboubakr Elnashar

V. Doppler
A. Umbilical artery Doppler
Idea:
Umbilical Arterial Flow is normally of low resistance.
In hypoxic states:
relative placental hypoxia:
reactive VC of umbilical artery:
higher resistance:
decrease in diastolic flow
Aboubakr Elnashar

Doppler indices
Aboubakr Elnashar

 Interpretation:
 Resistance index
 Enddiastolic flow
 Systolic/diastolic ratio
 Pulsatility index
 Diastolic average ratio
Aboubakr Elnashar

•Resistance index:
Best ability to predict abnormal outcomes
(RCOG,2002 Evidence level II)
 Normal pregnancy:
{progressive increase in end-diastolic velocity
{growth& dilatation of the umbilical circulation}:
Resistance index falls.
Fetal growth restriction and/or PET:
> 0.72 is outside the normal limits from 26 w.
Aboubakr Elnashar

•End Diastolic flow
In fetal growth restriction and/or preeclampsia:
reduced, then
absent (AED) or
reversed (RED) in severe cases
Absent or reversed:
Fetal distress is almost certain:
Immediate BPP or NST or
Delivery may be indicated.
Aboubakr Elnashar

•S/D
Should be <3.
Small increases in S/D= 3-5:
chronic intrauterine disease manifest by
IUGR.
Not strictly useful:
{1. low sensitivity.
2. Gestation age dependent}.
Aboubakr Elnashar

Normal
Absent
Reversed
Aboubakr Elnashar

Absent
Reversed
Aboubakr Elnashar

Advantages:
1. In low risk
No benefit on mother or baby
(The Cochrane Library, 2003)
Aboubakr Elnashar

2. In high risk:
 Reduction of
perinatal morbidity and mortality
number of antenatal admissions
inductions of labor
resources compared with CTG
(Grade A RCOG, 2002; The Cochrane Library, 2003)
 Comparing FHR monitoring, FBP and umbilical
artery Doppler:
only umbilical artery Doppler had value in predicting
poor perinatal outcomes in SGA
Aboubakr Elnashar

 Frequency of monitoring in SGA fetuses with
normal Doppler:
 A 4-week U/S measurement interval was shown to
be superior to a 2-week interval, in terms of reducing
the false –positive rate (Owen et al, 2001).
 Once/2w (Fortnightly) scans should be undertaken
where
1. linear growth velocity is not maintained or
2. AC is below the third centile (IV)
Aboubakr Elnashar

B. Middle cerebral artery peak systolic velocity
(MCA-PSV)
The most significant breakthrough in the
surveillance of the potentially anemic fetus
Based on:
In fetal anemia:
Enhanced fetal cardiac output and
Decrease in blood viscosity:
Increased blood flow velocity
preferentially shunt blood to brain faster
most pronounced MCA PSV
Aboubakr Elnashar

Frequency
•Initiated: 18 w
•Repeated: every 1–2 w as the clinical situation
MCA waveforms in an anemic fetus
requiring serial transfusions for severe Rh
(D) disease.
The peak systolic velocities of 62, 50, and
61 cm per second (top to bottom)
corresponded to fetal hematocrits of 19%,
44%, and 32%, before, at the time of, and a
week after the first intravascular
transfusion, respectively.
Aboubakr Elnashar

Advantage
More sensitive for predicting
f anemia than the ΔOD450
(Recent studies)
Alternative to serial
amniocenteses
Excellent noninvasive tool
for the monitoring of f anemia.
Aboubakr Elnashar

c. Uterine artery Doppler
 limited use in predicting FGR and perinatal
death (Grade A, RCOG,2002).
 Abnormal uterine artery suggest:
maternal cause for the growth restriction
 Normal uterine artery Doppler suggest:
fetal cause
Aboubakr Elnashar

UAD: Normal
UAD: notch,
decreased diastolic
flow
Aboubakr Elnashar

Prediction of preeclampsia
(Uterine Doppler velocimetry)
 Persistence of a
Diastolic Notch in
uterine artery
waveform after 24 w
 Systolic/diastolic ratio
>2.6
 RI > 0.58 after 24
weeks.
Systole
Diastole
Aboubakr Elnashar

1. CTG, must not form the sole basis for the
assessment of the fetus.
2. Computerized CTG may well be more effective
than standard CTG.
3. Formal assessment of the BPP does not
appear to hold any advantage over
assessment of liquor volume alone.
4. Where fetal growth restriction is suspected,
fetal biometry and assessment of umbilical
artery waveforms by Doppler ultrasonography
should be incorporated.
Aboubakr Elnashar

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Antepartum Fetal Surveillance: Aboubakr Elnashar

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