Antepartum fetal surveillance aims to prevent fetal death and avoid unnecessary interventions. Methods include fetal movement count, uterine growth assessment, antepartum fetal heart rate testing like nonstress tests and contraction stress tests, biophysical profile, and Doppler velocimetry. Abnormal test results may indicate fetal compromise and require additional testing or delivery depending on gestational age. Multiple variables are assessed and scored in the biophysical profile to evaluate acute and chronic fetal well-being and oxygenation status. Normal test results predict good neonatal outcomes while abnormal results indicate increasing levels of suspected fetal acidosis requiring intervention.

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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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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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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6. • Methods to quantify fetal movements
–Maternal subjective perception
–Visualization with u/s
–tocodynamometer
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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25. Contraindication for CST
• PROM
• Cervical incompetence
• Multiple preg.
• Classical c/s
• Non- reactve NST etc
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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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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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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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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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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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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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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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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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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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39. THANK YOU!!!