CTG: Antepartum

1. Aboubakr Elnashar
Benha university Hospital, Egypt

2. Aboubakr Elnashar

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

4. 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
f. body movements: FH acceleration
Aboubakr Elnashar

5. 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

6. Aboubakr Elnashar

7. 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

8. I. Fetal movements counting (FMC)
II. FHR 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

9. FHR recording
1.CTG
2.NST
3.Contraction stress test
4.Nipple stimulation test
5.Acoustic stimulation test
6.Computerized CTG
Aboubakr Elnashar

10. 1. FHR tracings (CTG)
METHOD
Simultaneous recordings are performed by 2
separate transducers:
1st for FHR
2nd for UC
Aboubakr Elnashar

11. 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

12. 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

13. Aboubakr Elnashar

14. Abnormal/Pathological Trace -
 Baseline FHR: <100 b/m or > 170 b/m
 No area of normal baseline variability
 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
 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

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

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

17. MANAGEMENT:
 Normal/Reassuring Trace –
repeat and/or estimate AFI if considered necessary
acc to the cl situation and indication for testing.
 Suspicious/Equivocal Trace –
 Continue for up to 60 min {determine the
presence of f 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

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

19. 2. The Non-Stress Test (NST)
(Hammacher et al, 1960)
Idea:
• FHR accelerations:
linked closely with f 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

20. 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

21.  In the event of lack of f 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

22. 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

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

24. 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)
Reactive nonstress
reliable screening indicator of f wellbeing in
women presenting with perception of RFM in 3rd T
Abnormal pregnancy outcomes:
more common when initial CTG was non reactive
(Daly et al, 2011)
Aboubakr Elnashar

25. 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

26. 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 f
wellbeing {Ia}
Aboubakr Elnashar

27. 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

28. 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

29. 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

30. 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

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

32. CST: negative
Aboubakr Elnashar

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

34. 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

35. 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

36. 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

37. 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

38. 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

39. 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

40. Aboubakr Elnashar

41. 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

42. 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. F breathing stops (BPP)
4. F movement stops (BPP)
5. F tone absent (BPP)
6. A F 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

43. OBSERVATION CRITERIA FOR
PRESENT
CRITERIA FOR
NEGATIVE
F Tone 1 episode of flexion-
extension-flexion in 30
min
No episodes of flexion-
extension-flexion in 30
minutes
F Movement 3 gross body
movements in 30
min
Less than 3 gross body
movements in 30 minutes
F Breathing 1 episode of
rhythmic breathing
in 30 min
No episodes of rhythmic
breathing in 30 minutes
A FV 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

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

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

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

47. 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

48.  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

49. 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

50.  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

51. 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

52. 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

53. CONCLUSIONS
Aboubakr Elnashar

54. 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

55. Aboubakr Elnashar
Aboubakr Elnashar