1. ANTEPARTUM
FETAL
MONITERING
Prof. M.C.Bansal
MBBS., MS., FICOG., MICOG.
Founder Principal & Controller,
Jhalawar Medical College & Hospital Jjalawar.
MGMC & Hospital , sitapura ., Jaipur

2. ANTEPARTUM FETAL MONITORING
 Two thirds of fetal deaths occur before the onset of labor,
many of which are due to uteroplacental insufficiency.
 No single test can detect abn with 100% accuracy
 Ideal detection: allows intervention before fetal death or
damage from asphyxia.
 Preferable: treat disease process and allow fetus to go to
term.
 DRAWBACK- false positive / negative results may cause
undue intervention and lead to premature iatrogenic delivery
or fetal compromise.

3. METHODS OF ASSESSMENT
•Assessment of Uterine growth
•Fetal movement counting
•Non stress test- indicator of fetal health.
•Contraction stress test – indicator of U.P func.
•Fetal Biophysical profile
•Modified Biophysical profile
•Doppler velocimetry
•Percutaneous umbilical blood sampling

4. Occurs due to inadequate delivery of nutritive &
respiratory substt to fetal tissues.
Can be due to:-
Inadequate exchange
Maternal Fetal uptake
within placenta due
inadequacy to problems
to-
deliver nutrients &
oxygen through
1. increased
placenta
thickness
2. reduced blood flow
3. decreased sf area

5. SEQUENCE OF FETAL
DETERIORATION/COMPROMISE
Generalized Fetal Well Being with some Nutritional
Compromise
Fetal Growth Retardation with Marginal Placental
Dysfunction
Fetal Hypoxia under Stress cond. with Decreasing
Respiratory Function
Asphyxia/Death/Residual effects with Profound Respiratory
Compromise

7. MATERNAL RISK FACTORS OF UPI
1. PRE-ECLAMPSIA , CHRONIC HYPERTENSION
2. COLLAGEN VASCULAR DISEASES
3. DIABETES MELLITUS
4. RENAL DISORDERS
5. BLOOD- MATERNAL ANAEMIA, RH
SENSITISATION
6. HYPERTHYROIDISM
7. THROMBOPHELIA
8. CYANOTIC HEART DISEASE
9. POST DATED PREGNANCY
10.FETAL GROWTH RESTRICTION

8. UTERINE GROWTH ASSESSMENT
General rule: Fundal height in centimeters = weeks of
gestation (2nd trim.)
Johnson’s formula = [Ht. of uterus above symphysis (cm)
– 12 (vx at or above ischial spines)
OR 11 (vx below ischial spines)] x 155
Exceptions: Maternal Obesity, Multiple
Gestation, Polyhydramnios, Abnormal Fetal
Lie, Oligohydramnios, Low Fetal Station, and Fetal Growth
Restriction.
Abnormalities of fundal height should lead to further

9. FETAL MOVEMENT
COUNTING
MATERNAL PERCEPTION OF REDUCTION IN MOVEMENTS MAY
BE A RED FLAG SIGN TO IMPENDING FETAL DISTRESS.

10. •4 fetal behaviour states as described by Nijhuis & colleagues (1982)
based on fetal movements, fetal heart rate & eye movements :-
1. State 1F- Quiescent state- quiet sleep with narrow oscillatory
bandwidth of fetal heart rate.
2. State 2F- Frequent gross body movements, cont. eye
movements, wider oscillations of fetal heart rate. (=REM of
neonate)
3. State 3F- Continuous eye movements in absence of body
movements and heart rate accelerations. The existence of such
state is doubtful
4. State 4F- Vigorous body movements with constt eye movements
and heart rate accelerations.

11.  USG observations show that fetus has gross body movements
approx 10% of the time and as many as 30 movements can occur in
an hour.
Most commonly used method is “ COUNT TO 10”
(Moore et all 1989) [Am J Obs-Gyn]
Patients are instructed to count until they reach 10 movements.
If such 10 movements are noticed in 10 hours, most probably the
fetus is in good health. (1 movement in each hour).
If mother reports <10 movements in 10 hours OR there is doubling
of hours usually required to complete 10 movements, she should be
subjected to further evaluation.

12. • Studies have indicated a good correlation b/w fetal movements
perceived by the mother and those picked on a real time scan.
• Periods of fetal activity lasts for about 40 mins and that of rest
about 20 mins. The mother usually perceives 70-80% of these
movements.
• Passive fetal movements begin by about 7wks and become more
coordinated towards end of pregnancy. (Vindla and James 1995)
• Beyond 8 wks, body movements are never absent for periods
exceeding 13 minutes. (De Vries and co worker's 1985)
•Between 20-30 wks, general body movements become organised and
fetus starts to show „rest-activity cycles‟.
(Sorokin and co-workers 1982)

13. FACTORS AFFECTING PERCEPTION OF
MOVEMENTS
 Maternal obesity
 Excessive liquor
 Placental site (?)
 Fetal malformations

14. oMost commonly used test. The patient placed in semi
fowler‟s position.
oNon invasive, easy to perform, interpret and readily
accepted by patients.
oTest looks for presence of fetal heart rate (FHR)
accelerations associated with fetal movements.
oThis reflex involves the cerebral cortex, and is affected
by physiological (fetal sleep) or pathological influences
(fetal hypoxia) on fetal brain.

15. •Two normal patterns of NST are:-
a. Reactive - 2/more accelerations of FHR of min 15
beats/min, lasting for atleast 15 secs from baseline
to baseline within 20 mins obsv pd, associated with
fetal movements (as perceived by the mother).

16. b. Non Reactive- Lack of such accelerations for a pd
of 40 mins. (20 mins as per normal obsv pd +
additional 20 mins)

17.  Introduced by Zimmer et all, 1993.
Stimulation via an artificial larynx, over the fetal head along with
NST attached & producing vibratory acoustic stimulus of approx 80Hz
and 82dB.
A healthy fetus responds with a sudden movement (Startle
Response) followed by FHR acceleration.
Response to VAS is gestational age dependant, viz, a fetus of less
than 24 wks doesn‟t respond to it.
Between :-24-27wks 30%
27-30wks 86% fetuses will respond to the stimulus.
>31wks 90%

18. NST is to be read keeping in account all the variables namely,
1. Baseline FHR
2. Variability of FHR
3. Presence /absence of decelerations
4. Presence /absence of accelerations
each one being separately analysed.
Normal baseline FHR IS 110-160 bpm.
>160 is tachycardia & <110 is bradycardia.
Variability is the most imp parameter to be read and interpreted. It
depends upon interactions of fetal sympathetic & parasympathetic
nervous systems.
It‟s influenced by gestational age, fetal tachycardia, maternal
medications, congenital anomalies and fetal acidosis.
A non reactive NST in presence of variability suggests a false positive
reading

19. drawbacks
•Can‟t pick up early fetal compromise. Though, this concern hasn‟t been
proven in clinical trials and hasn‟t effected the use of NST as a primary tool
for diagnosis.
•Use of test alone without realising the significance of other tests which may
be better for the given patient. Eg. In postdated pregnancies, simultn
assessment of amniotic fluid volume is necessary.
(Kontopoulos and Vintzileos, 2004)
•Gandhi (2003), emphasised that though false positive rate ranges between
65-70%.
•A cumulative view of 50,000 cases (Ware and Devoe, 1994) revealed a
perinatal mortality of 6.2/1000.
He also states that diagnostic value of NST remains as good as CST and is
simpler to perform.

20. Devoe, L, Glob. libr. women's med.,
(ISSN: 1756-2228) 2008; DOI
10.3843/GLOWM.10210

22. Based on experimental evidence showing that
uteroplacental blood flow decreases markedly or ceases
during each uterine contraction. Thus, uterine
contractions cause a hypoxic state that a normal, healthy
fetus can tolerate without difficulty.
In contrast, fetus with acute/chronic problems will not be
able to tolerate such a decrease in oxygen supply & will
demonstrate decelerations of FHR following contraction.
Contractions can be- a. spontaneously occuring
b. induced with oxytocin drip
( predictable response)
c. nipple stimulation
(unpredictable response)

23. HOW TO PERFORM CST
1. Patient on semi fowler‟s position.
2. Tocographic equipment applied to maternal abdomen, observe uterine
activity with FHR variations every 15-20 mins.
Spontaneous contractions present in many cases. If not induction of
contractions may be necessitated.
3. Start IV oxytocin at 0.5 mU/minute, using pump. Double the rate every 15-
20 mins till 3 contractions, of 40-60 secs occur within 10 mins time.
Amount required to achieve adequate contractions usually below
16 mU/ml.
Alternately, warm towel can be used to stimulate the nipples.
4. After completion uterine contractions and FHR should be monitered till
they return to baseline. If not, subcutn admin of 250 mg of terbutaline
reqd to paralyze the uterus.

24. End point of CST is presence or absence of decelerations of FHR with
uterine contractions.
Late decelerations are one of the earliest indicators of fetal compromise &
appear due to loss of variability, decreased movement, loss of tone.
The test is infrequently used due to:-
1. long obsv periods by trained professionals.
2. risks and contraindications.
*Positive: presence of late decelerations with at least 50% of the
contractions
*Negative: no late or significant variable decelerations
*Equivocal—Suspicious: presence of late decelerations with fewer than
50% of contractions) or significant variable decelerations
*Equivocal—Tachysystole: Presence of contractions that occur more
frequently than every 2 minutes or last longer than 90 seconds in the
presence of late decelerations
*Equivocal—Unsatisfactory: Fewer than three contractions occur within
10 minutes, or a tracing quality that cannot be interpreted

25. CONTRAINDICATIONS
1. Placenta praevia
2. Prior classical cesarean section
3. Prior extensive uterine surgery
4. Preterm labour / High risk of preterm labour
5. PROM
6. Incompetent os

26. A. Negative CST. Absence
of late decelerations, often
occasional accelerations.
B. Positive CST. Recurrent
uniform late decelerations
present.
C. CST. Variable
decelerations present.
D. Hyperstimulation.
Prolonged contraction with
reflexive deceleration.

27. Positive CST conveys the strong possibility that placental respiratory
insufficiency is present, although it does not indicate the probable duration
or progress of this condition.
In addition, the positive CST conveys much higher risk of fetal distress, low
5-minute Apgar scores, and IUGR than does a negative test.
Devoe, L, Glob. libr. women's med.,
(ISSN: 1756-2228) 2008; DOI
10.3843/GLOWM.10210

28. Combines NST with ultrasound assessment of 4 variables.
5 parameters are-
•Fetal Breathing Movements- 30 secs sustained movmnt in 30 mins
obsv.
•Fetal Movement- 3/more gross body movements in 30 mins obsv
•Fetal Tone- 1/ more movement from flexion to extension and
return to flexion.
•FHR reactivity- 2/more accelerations of 15bpm, lasting atleast 15
secs.
•Fluid Volume- at least 2 pockets meas. 2cm in 2 perpendicular
planes.
Variables are dependant on integrity of fetal CNS & are affected in fetal
compromise.

29. Each parameter assigned points-- 2 if present/normal.
0 if absent/abnormal.
A BPP normally is not performed before the second half of a pregnancy, since
fetal breathing movements do not occur in the first half.
A BPP of 8 or 10 is generally considered reassuring, as long as score of 8
doesn‟t include abnormal fluid volume.
PRESENCE OF OLIGOHYDRAMNIOS DEMANDS FURTHER TESTING
NO MATTER WHAT THE SCORE IS.
A score of 6 is Equivocal and requires further testing to verify findings.
A score of 4/less suggests fetal compromise.

30. BPP variables are dependant on fetal CNS development acc to
gestational age.
Fetal tone & movement appear b/w 7-9 wks and require activity of brain
cortex.
Fetal breathing movements begin at 20-21 wks & depend on centres on ventral
surface of 4th ventricle.
FHR reactivity appears b/w 28-30 wks & controlled by post
hypothalamus, upper medulla.
Sensitivity of each centre to hypoxia is different & ones which develop earlier
are more resistant to effects of fetal hypoxia.
First manifestation of fetal acidosis- nonreactive NST, lack of fetal breathing
movements. Decreased body movements and loss of tone occur with severe
compromise.

31. Vintzileos et al (1987) , Clark et al (1989), Miller et al (1996)
 Excellent test for primary fetal surveillance.
Combines use of NST with VAS, and Amniotic Fluid Index
Test has:-
excellent positive & negative predictive values
easy to interpret
clearly defined end points
average time needed is 20 mins

32. Following guidelines are useful while reading the results:-
1. Both NST and AFI are normal, cont weekly fetal monitoring.
2. Both tests abnormal; a) >36 wks, best option is delivery
b) <36 wks, individualized treatment
3. NST reactive, but AFI low, search for causes of UPI or undiagnosed ROM.
4. AFI normal, but NST non reactive, further testing with Doppler, CST, BPP.

33. *Non invasive technique to assess placental blood flow to the fetus.
*Uses waveforms to describe Systolic (S) & Diastolic (D) blood flow through
vessels.
S
D
*Three commonly used ratios are:-
a. S/D Ratio
b. S-D/S = Resistance Index
c. S-D/Mean = Pulsatility Index

34. Acc to Trudinger (2007);
>40% of total fetal ventricular output directed to placenta
obliteration of utero placental circulation
increases afterload
further hypoxia
dilatation & redistribution of MCA blood flow
pressure rises in Ductus Venosus due to
increased afterload to right side of fetal heart

35. •Vessel normally has forward flow throughout cardiac cycle & diastolic flow
increases as gestation advances.
•So, S/D ratio decreases as gestation advances, from 4 at 20 wks to <3
by 30 wks & finally 2 at term.
•S/D ratio is taken as abnormal if it‟s above 95th percentile for
gestational age OR diastolic flow is absent or reversed.
•A resistance index > 0.72 is greater than the normal limits from 26 weeks
gestation onwards.

36. • Abnormal waveforms can be present for weeks before there is evidence of
fetal compromise.
These are a marker of a high risk situation and should not normally be used
in isolation as an indication for delivery.
•Most would consider delivering a fetus with absent end-diastolic
velocity from about thirty two weeks gestation following
administration of corticosteroids.
•However, reversal of end diastolic blood flow is an ominous sign &
predicts severe fetal compromise, possible death, requiring urgent
delivery of the viable fetus.

37. Konjoe & colleagues (2001) [Br J of Obs & Gyn]
Doppler studies of MCA showed, hypoxic fetii attempt brain sparing by
reducing cerebrovascular impedance & thus reducing blood flow.
In growth restricted fetii this effect shows reversal.
The effect however, isn‟t protective, rather indicates negatively on the fetal
health.

38. INCREASED DIASTOLIC
FLOW, due to reduced resistance.
NORMAL doppler flow
Highly reduced resistance, shown by
FURTHER INCREASE OF
DIASTOLIC FLOW.
REVERSAL OF DIASTOLIC
FLOW, indicative of severe fetal
compromise.

39. •F. Daffos (1983-1985)
•22 G / Finer needle needed.
•Can be performed at any site on umbilical cord, but placental insertion
preferred.
•One should avoid piercing through the placenta.

40. INDICATIONS
a) Rapid Karyotype In Fetuses Detected With Anomalies On USG.
b) Fetal Hemolytic Disease
c) Suspected Fetal Viral Infection
d) Non Immunologic Hydrops Fetalis
e) Suspected Fetal Thrombocytopenia
f) Twin To Twin Transfusion
g) Fetal Heamoglobinopathies

41. RISKS
BLEEDING FROM
PUNCTURE SITE
VASO VAGAL REFLEX
FETAL BRADYCARDIA

42. Ideally an obstetrician should adequately inform the patient of all
the pros and cons of any test method being employed, and the
efficacy and limitations of the same.
In many instances, failing to do so, may cause the patient to have
unreasonable expectations which when unfulfilled may lead to
animosity and disappointment towards the doctor and cause
medico-legal problems

43. SOURCES
1. WILLIAMS TEXTBOOK OF OBSTETRICS 23RD EDITION.
2. PRACTICAL BOOK TO HIGH RISK PREGNANCY 3RD
EDITION by FERNANDO ARIAS.