a practical presentation tackling intra-partum fetal assessment with examples.

1. Intra-Partum Fetal
Assessment
Dr/ Mahmoud Abdelaleem
A Professor of Obstetrcis and Gynecology
Diploma of reproductive medicine, Geneva

2. Definitions
• Labor interferes with the umbilical and uteroplacental
blood flow and affects the fetal gas exchange. If this is
prolonged, it will lead to mild metabolic acidosis followed
by respiratory acidosis.
• Acidosis: increased hydrogen ion (decreased pH)
concentration in tissues.
• Acidemia: Decreased pH in blood.
• Hypoxia: decreased oxygen concentration in tissues.
• Hypoxemia: Decreased oxygen level in blood
• Asphyxia: severe state of fetal gas exchange leading to
hypoxia, hypercarbia, and acidosis.
• Fetal distress: a state of fetal jeopardy that may or may
not be caused by asphyxia.

3. Chart for wellbeing
Fetus
Pregnancy
Antepartum Fetal Assessment
Aim
Living
No anomalies
Dates
No asphyxia
Methods
Clinical
Bioelectric
US-based
Labour
Intrapartum Fetal Assessment
Aim
No asphyxia
Methods
Clinical
Intermittent auscultation
Continuous auscultation
Direct pH assay
Postnatal
Postpartum
Neonatal assessment
Aim
No asphyxia
No anomalies
Dates
Methods
Clinical
APGAR score
Direct pH assay

4. Causes of Intrapartum Fetal Asphyxia

5. Diagnosis of Intrapartum Fetal Asphyxia
• Clinical:
– Meconium in the amniotic fluid.
– Postnatal: low APGAR score.
• Fetal heart rate monitoring:
– Intermittent: using Pinard stethoscope.
– Continuous: continuous electronic fetal heart rate monitoring.
– Fetal heart rate response to:
• Scalp stimulation.
• VAST.
• Biochemical:
– Determination of fetal scalp blood gas
– Postnatal: umbilical cord blood gas.

6. Meconium in the amniotic fluid
• Meconium: dark green mucilaginous material in the intestine of the
full term fetus.
• Composition:
– Sloughed intestinal epithelial cells.
– Gastrointestinal secretions.
– Swallowed debris "hair, vernix, skin cells".
• It shouldn't pass in-utero as it is aspirated by the fetus leading to
"Meconium aspiration syndrome" manifested postnatally and is
diagnosed by finding Meconium below the level of vocal cord using
laryngoscope.
• It is classified either into:
– According to consistency:
• Thin: slightly green A.F. NO particulate matter.
• Thick: thick, green stained A.F. with particulate matter; the dangerous type.
• Moderate: in between the above 2 extremes.
– According to the time it appears:
• Early: noted before or during the active phase of labour.
• Late: when passes after clear fluid has been noted previously.

7. • Pathophysiology:
– How it passes in utero:
• Fetal hypoxia vasoconstriction of the fetal gut stimulation of fetal peristalsis and sphincter
relaxation passage of Meconium.
• Cord compression vagal stimulation meconium passage.
– Effect on the fetus:
• With deep, gasping respiration inutero, Meconium is carried down the airway to the lungs " meconium
aspiration syndrome" ---->
• Chemical pneumonitis.
• Occlusion of the airway.
• Trapping of air.
• Persistent pulmonary hypertension of the newborn.

8. Diagnosis of Intrapartum Fetal Asphyxia
• Clinical:
– Meconium in the amniotic fluid.
– Postnatal: low APGAR score.
• Fetal heart rate monitoring:
– Intermittent: using Pinard stethoscope.
– Continuous: continuous electronic fetal heart rate monitoring.
– Fetal heart rate response to:
• Scalp stimulation.
• VAST.
• Biochemical:
– Determination of fetal scalp blood gas
– Postnatal: umbilical cord blood gas.

9. Intermittent Auscultation
Method
Frequency
Value

10. Diagnosis of Intrapartum Fetal Asphyxia
• Clinical:
– Meconium in the amniotic fluid.
– Postnatal: low APGAR score.
• Fetal heart rate monitoring:
– Intermittent: using Pinard stethoscope.
– Continuous: continuous electronic fetal heart rate monitoring.
– Fetal heart rate response to:
• Scalp stimulation.
• VAST.
• Biochemical:
– Determination of fetal scalp blood gas
– Postnatal: umbilical cord blood gas.

12. Electronic fetal heart rate monitoring
• Rationale: continuous monitoring of the FHR pattern aiming at early
detection of any evidence of fetal asphyxia thus provide a timed
interference that may improve the perinatal outcome.
• Disadvantages: expensive, limits the movement of the patient, and
shown to increase the incidence of C.S.
• Technique: with woman in the semi-fowler position,
– Detection of pattern of uterine contractions; by either:
• External tocodynamometry: before rupture of membranes
• Internal tocodynamometry: after rupture of membranes; by an intrauterine
catheter sensor. More accurate
– Detection of FHR pattern changes: by either:
• External cadiography: using a Doppler U.S.
• Internal cadiography: using an electrode attached to the fetal scalp
• Comment and interpretation: searching for DECELERATIONS in
relation to the uterine contraction.

16. Early
• Slow
• Starts early with the contraction
• Nadir with the peak of the contraction
• Ends before the end of the contraction
• Cause: Head compression
• Transient decrease in cerebral blood flow.

19. Variable
• Abrupt
• Onset: Having no relation to the contraction
• Nadir: No relation to the contraction
• Offset: No relation to the contraction
• Cause: Umbilical cord compressionCord
compression  increase in peripheral resistance
& elevation of B.P. & reflex bradycardia.

20. • Variable decelerations are classified into 3
grades:
– Mild: FHR is > 80 bpm and deceleration lasts
for < 30 sec.
– Moderate: FHR is 70 -80 bpm and
deceleration lasts for 30-60 sec.
– Severe: FHR is <70 bpm and deceleration
lasts for > 60 sec.

22. Late
• Abrupt.
• Onset: occurs up to 30 sec. after the start of the
contraction
• Nadir: After the peak of the contraction
• Offset: After the end of the contraction
• Cause: Uteroplacental insufficiencyDrop of intervillous
oxygen content - activation of chemoreceptors and
sympathetic activation - increased B.P. - activation
of baroreceptors then vagal tone.

24. Prolonged deceleration
• a type of decelerations that is prolonged
for ≥60 sec, it is due to:
• Umbilical cord prolapse.
• Tetanic uterine contractions.
• Rapid fetal descent in the birth canal.
• Placental abruption.
• Sudden profound maternal hypotension.

26. Categories of fetuses
• According to the presence or absence
of decelerations, FHR pattern can be
classified into one of three categories;
each is carrying a different prognostic
value and thus requires special
management:

27. Reassuring (Normal) (Physiology)
(Category I)
Normal baseline.
Normal variability.
Normal accelerations.
No decelerations.
Action

29. Non- reassuring pattern
(suspicious) (category II)
• Decrease variability without
decelerations.
• Mild Variable decelerations.
• Late decelerations with adequate
variability
Action
Because of high false positive rate, one of 3 methods should be done
to verify the diagnosis.

31. • Methods done to verify the diagnosis of
fetal asphyxia if the FHR pattern is non-
reassauring:
• Scalp pH determination: the most
accurate.
• FHR response to VAST.
• FHR response to scalp stimulation.

32. Fetal scalp pH ( blood gases)
• It is the most accurate method for determining the acid-base state
(diagnosing fetal asphyxia) during labour.
• Technique: a specially –designed guarded blade is thrusted into the
scalp and 15 µl of fatal blood are collected into a capillary tube
• Values:
– Normal: >7.24
– Pre-acidotic: 7.24 – 7.20.
– Acidotic: < 7.20 (the lowest accepted normal value).
– Profound acidosis: < 7.18
• Indications:
• Meconium stained A.F.
• Non-reassuring FHR pattern.
• Complicated delivery.
• Pre- or post- term.
• Complications: rare; bleeding, infections.

33. Ominous (pathological) (abnormal)
(category III)
The severest form
Action :Imminent delivery

34. Summary

35. Summary II

39. Intrauterine fetal resuscitation
• Done in cases of fetal asphyxia during the time
before the delivery to improve the outcome: Also
may help in determining the fate of the non-
reassuring FHR pattern
– Nasal Oxygen to the mother.
– Change the maternal position to the left lateral
position.
– Tocolytic is given: terbutaline 250 µg subcutaneously.
– Stop oxytocin if present.
– Intravascular volume expansion using crystalloid
solutions; e.g. glucose infusion.
– Intrapartum amnioinfusion.

40. “A-B-C-D” approach to the management of a
Category-II FHR tracing is
Assess the oxygen pathway
Begin conservative corrective measures
Clear obstacles to rapid delivery
Determine decision-to delivery time.