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1. Antepartum Fetal Surveillance

2. Introduction
• 80% fetal death occurs in the antepartum
period and many of the fetal deaths occur in
woman at risk for uteroplacental insufficiency
• Goals antepartum fetal surveillance
– Prevention of fetal death
– Avoidance of unnecessary interventions
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By: Natnael A.

3. Indications
• Woman at high risk for uteroplacental
insufficiency
• Maternal chronic medical disorders
» DM, chronic HTN,chronic lung dx, renal/cardic dx etc
• Pregnancy related conditions: Postterm pregnancy, PIH,
multiple gestations, unexplainable previous perinatal death,
IUGR, Rh sensitized pregnancy, PROM,etc
• When other tests suggest fetal compromise:
decreased maternal perception of fetal
movement, suspected IUGR, oligohydramnios…
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By: Natnael A.

4. Methods of antepartum fetal
surveillance
1) Fetal movement count
2) Assesment of uterine growth
3) Antepartum FHR testing
 NST, CST
4) BPP
5) Doppler velocimetry
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By: Natnael A.

5. Fetal movement
• Begins as early as 7th wk but becomes more
sophisticated and coordinated near term
• Usually 1st percieved by mother at 17-20wks
(quickening)
• mother can appreciate 50% of isolated limb
movements and 80% of trunk and limb movements
when correlated with U/S
• Fetal sleep-awake cycles are important determinants of
fetal activity; varies from 20-75 min
• Peaks b/n 9pm and 1am;a time when maternal glucose
levels are falling
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By: Natnael A.

6. • Methods to quantify fetal movements
–Maternal subjective perception
–Visualization with u/s
–tocodynamometer
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By: Natnael A.

7. • Maternal fetal movement count
Methods
Sadovsky et al.
• Fetal movement count for 30-60min ,2-3x daily
if <3movements/60min or no movement for >12hrs
further evaluation is indicated
Rayburn et al
• Count for at least 60min/day
<3 mov’ts /60min for two consecutive days may be a sign
of fetal compromise
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By: Natnael A.

8. Cont’d
Cardiff count to ten (pearson and weaver)
at least 10 movements should be perceived in 12hrs
disadvantage: poor sensitivity
Factors that affect perception of fetal
movements:
• Maternal , placental ,fetal
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By: Natnael A.

9. FH measurement
• Techniques
1) finger method
2) Tape measure techniques("McDonald measurement“)
– SFH in cm equals the GA best between 18 and 34
wks.
– Discrepancy of >2-3wks is considered abnormal Ix
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By: Natnael A.

10. Antepartum FHR assessment
Two types FHR patterns
Reassuring
Nonreassuring
Regulation of FHR
 FHR and its conduction systems develop b/n 3 and
6wks
 Factors that regulate FHR become functional in
later GA
 NS ( parasympathetic (PNS) and sympathetic
(SNS)) regulates the FHR patterns
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By: Natnael A.

11. Cont’d
 FHR changes result from moment to moment
autonomic modulations from medullary
cardiorespiratory centers in response to inputs
from
Chemoreceptor
Baroreceptor
Hormonal regulations
Blood volume controls
CNS activities ,such as arousal and sleeping
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By: Natnael A.

12. Effects of GA on FHR
– The PNS exerts greater influence on FHR as GA advances (i.e
Slowing of FHR with advancing GA)
– FHR variability is rare before 24wks but its absence after 28
wks is abnormal
• Advancing GA is also associated with increased frequency and
amplitude of FHR acceleration, w/c are modulated by PNS
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By: Natnael A.

13. Cardiovascular response to hypoxia
• Fetal oxygenation depends upon:
oAdequate maternal oxygenation
oUteroplacental blood flow and
oDistribution of oxygenated blood to fetal tissues
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By: Natnael A.

14. Interpretation of FHR tracing
• Always needs to be interpreted in the context of:
the GA
Prior results of fetal assessment
Maternal conditions(including medications)
Fetal conditions(e.g IUGR, anaemia ,
arrhythmia)
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By: Natnael A.

15. Antepartum FHR assessment…
• Currently, it’s generally performed in
pregnancies in which the risk of fetal death is
known to be ed:
Pregnancies at risk uteroplacental insufficiencies
Fetal disorders, or any other condition potentially
associated with increased risk of fetal death
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By: Natnael A.

16. Nonstress test (NST)
• A short term indicator of fetal acid-base status
• It’s the most widely used primary testing
method of fetal well being assessment
• FHR accelerations occur during fetal
movement
• Can be initiated when the fetal neurological
maturity enables FHR accelerations to
occur(typically at 26-28wks)  the fetus is
believed to be at ed risk of death
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By: Natnael A.

17.  Advantage:
Cheap, simple, and can be performed in any
setting
No direct maternal or fetal risks
 disadv.: high FP rate( 50-60%)
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By: Natnael A.

18. How to do NST
• Patient in lateral tilt position
• FHR tracing is observed for 40min;using
Doppler or CTG
• Healthy fetuses display normal oscillations
and fluctuations of the baseline FHR
• Absence of FHR accelerations seems to depict
CNS depression caused by hypoxia, drugs
,fetal sleep or congenital anomalies
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By: Natnael A.

19. Interpretation
A. Reactive NST:
If there is ≥2 FHR acceleration that peak at least
by 15bpm above baseline ,each lasting ≥15 sec,
and all occurring within 20min of beginning of the
test
Prior to 32wks >2 accelerations of atleast 10bpm,
lasting ≥10sec over 20min interval
Fetal death within 1wk of reactive NST =3-5/1000
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By: Natnael A.

20. Cont’d
B. Non-reactive NST
If criteria for reactivity are not met over 40min
Can be sign of fetal hypoxemia or acidosis
Other causes:(benign and temporary)
 Maternal drugs(e.g smoking,…)
 Fetal sleep or
 Fetal congenital anomalies or fetal
immaturity
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By: Natnael A.

21. Management of nonreactive NST
Options
Performing additional tests(eg. BPP, Doppler
velocimetry)
Modifying factors responsible for abnormal
test results if possible(eg. Correction of
maternal hypotension,…)
Delivery if term -fetal hypoxemia cannot be
definitively excluded
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By: Natnael A.

22. Contraction stress test
• A test of uteroplacental function
• FHR  uterine contractions are recorded
simultaneously with external monitor
• Contraction is induced either with oxytocin or
nipple stimulation ( at least 3/10’/40’’ )
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By: Natnael A.

23. Interpretation
Negative: no late/significant variable deceleration
Positive: late deceleration following ≥50% of
cont.(even if inadequate cont.)
Equivocal-suspicious: intermittent late dece. or
significant variable dece.
 equivocal- hyperstimulatory : FHR dece. that
occur in the presence of cont. more frequent
than every 2min. Or lasting >90sec
Unsatisfactory: fewer than 3cont.in 10min
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By: Natnael A.

24. Cont’d
 +ve CST may indicate ed fetal reserve  correlates with 20-
40% incidence of abn. FHR patterns during labor
 Equivocal-suspicious test with repetitive variable dece. is also
associated with abn.FHR patterns in labor
 If result is suspicious, suggests hyperstimulation or
unsatisfactory repeat after 24hrs
 b/c of high FP rate, +ve CST should be supported by BPP
 -Ve CST ,repeat weekly
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By: Natnael A.

25. Contraindication for CST
• PROM
• Cervical incompetence
• Multiple preg.
• Classical c/s
• Non- reactve NST etc
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By: Natnael A.

26. cont’d
Advantages:
Not affected by maternal drug ingestion
Not GA dependent
Disadv.
Expensive
Time consuming
Invasive(needs iv line)
Potentially risky b/c cont. is induced
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By: Natnael A.

27. FETAL BIOPHYSICAL PROFILE (BPP)
• Refers to the sonographic assessment of 5
discrete biophysical variables:
Fetal tone
Fetal movement
Fetal breathing movement
Results of NST 
AF volumes
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By: Natnael A.

28. Cont’d
• Activities that 1st appear in fetal development
(FT, FM) are the last to disappear and activities
that appear last (NST, FBM) are the 1st to
disappear in case of hypoxia  acidosis.
– FT=7.5-8.5wks
– FM=9wks
– FBM=20-21wks
– NST=24-28wks(but most reliable after 32wks)
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By: Natnael A.

29. Cont’d
• Acute variables
FT, FBM, FM,NST
Expandable in times of stress since they are
energy dependent  fetal O2 requirement
the most O2 sensitive centers are the
cardioregulatory neurones controlling the
coupling of FM  FHR acceleration and FB center
neurones
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By: Natnael A.

30. Cont’d
• Chronic variable
AFV
Fetal urine production primarily depends on renal
perfusion
Hypoxemia  redistribution of COP to the major
organsurine production  oligohydramnios
It takes 15days for a fetus to progress from
normal to abnormal AFV(in absence of ROM) 
23days to develop severe oligohydramnios
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By: Natnael A.

31. BPP scoring
COMPONENTS SCORE 2 SCORE O
NST/FHB reactive Non-reactive
FBM ≥1 episode of breathing
≥30sec within 30min
<30sec breathing within
30min
FM ≥3 discrete body or limb
mov’t within 30min
<3 discrete movement
FT ≥1 episode of extremity
extension  subsequent
return to flexion
No episode of
extension/flexion
AFV Largest single vertical
pocket >2cm
Largest single vertical
pocket ≤2cm
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By: Natnael A.

32. BPP score,interpretation  Mx
BPP score interpretation Recommended Mx
10 normal No intervention, repeat
test(wkly/2x wk)
8/10(NST not done)  
8/10AFV Suspect asphyxia delivery
6 Possible asphyxia •AFV delivery
•Normal AFV , GA> 36wks
deliver if Cx is favorable
If GA<36wks repeat test,
if ≤6 deliver
But if >6 repeat as per
protocol
4 Probable asphyxia Repeat test same day, if
BPP ≤6 deliver
0-2 Chronic Fetal asphyxia deliver
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By: Natnael A.

33. • Normal variables are highly predictive of a good
neonatal outcome
• Each abnormal variables may be associated with a
Fetal Pulse rate
• If the NST is reactive, do not need the u/s parameters
of the BPP, only the AFV would add additional
information
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By: Natnael A.

34. Clinical utility
• BPP is non-invasive, easily applied and highly accurate means
of predicting the presence of fetal acidemia
• Risk of fetal death within 1wk of a normal test was 0.8/1000
of women tested .
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By: Natnael A.

35. Cont’d
• Modified BPP
 developed to simplify the examination and
reduce the time necessary to complete testing
Combination of AFI and NST
 The rate of stillbirth within 1 wk of a normal test
is the same as with the standard BPP
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By: Natnael A.

36. Factors affecting test results
• Administration of antenatal corticosteroids
can be associated with transient FHR changes (a decrease in
variability) that typically return to baseline by day 4 after
treatment.
fetal breathing and body movement
• subclinical infection- controversial
may be associated with absence of FBM
 Preterm labor may be associated with absence of FB.
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By: Natnael A.

37. Doppler velocimetry
• Doppler U/S is a noninvasive technique to assess blood flow
(volume, rate) in fetal or maternal circulations umbilical A,
ductus venosus,….
• Maternal uterine artery Doppler velocimetry has also been
evaluated in efforts to predict placental dysfunction
• Doppler velocimetry is recommended as the primary
surveillance tool for monitoring pregnancies complicated
with IUGR due to uteroplacental insufficiency
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By: Natnael A.

38. Indications  frequency of testing
• Woman with high risk factor for fetal acidaemia
should undergo antepartum FS with eg.NST,
BPP…
• May be initiated as early as 26 wks but more
appropriate at 32-34wks
• Reassuring test should be repeated periodically
(weekly/2x wk)until delivery when high risk
condition persists
• Normal antepartum testing doesn’t preclude the
need for intrapartum fetal monitoring
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By: Natnael A.

39. THANK YOU!!!