methods of fetal monitoring during labour

1. Fetal health surveillance in
Labour
Mabuku Sankombo
201301623

2. Outline
• Introduction
• Labour
• High risk patients
• The fetal section of the partogram
• Intermitted Auscultation
• Electronic fetal monitoring
• Fetal scalp blood sampling
• Umbilical cord blood gas analysis

3. Introduction
• The goal of intrapartum fetal monitoring is to detect potential fetal
decompensation/distress, and to allow timely and effective
intervention to prevent damage or death.
• The fetal brain is the primary organ of interest but at present it is not
clinically feasible to assess its function. However, the FHR can be
assessed. The fact that changes in FHR precede brain injury is the
rationale for FHR monitoring.
• Timely response to abnormal FHR patterns might be effective in
preventing brain injury from birth asphyxia.

4. • The onset of labor is defined as regular, painful uterine contractions
resulting in progressive effacement and dilatation.
• The powerful uterine contractions may disrupt uteroplacental
exchange or compress the fetal head leading to fetal distress, fetal
hypoxia-acidosis then subsequently asphyxia.
• Active and vigilant fetal health surveillance is required during labour
in order to avoid the adverse sequelae of birth asphyxia; Hypoxic
ischaemic encephalopathy or cerebral palsy.
• Be even more vigilant for the high risk groups, that have other
predisposing factors which increase the likelihood of

5. Epidemiology
• Asphyxia/HIE in 2-9/1000 live births.
• Cerebral palsy in 1-2/1000 live births, but only 8-17% of CP cases
explained by probable perinatal asphyxia.
• Death rate ~11% in term infants, severe sequela in 0.3%o
• In premature infants incidence of HIE, deaths and handicap much
higher

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

7. Partograph: Fetal condition
• this part of the graph is used to monitor and assess fetal
condition
• 1 - Fetal heart rate
• 2 - Membranes and liquor
• 3 – Molding of the fetal skull bones.
• 4 - Caput

8. High Risk groups
Maternal conditions Fetal conditions Pregnancy Related
conditions
Intrapartum
Hypertension Fetal growth restriction Preeclampsia Oxytocin augmentation
Diabetes Mellitus Rh Isoimmunization Multiple pregnancy Epidural anaesthesia
Heart Diseases Fetal cardiac arrhythmias Post term pregnancy Vaginal bleeding in labor
Chronic Renal Disease Hydrops fetalis Decreased fetal movements Fresh meconium stained
liquor
Acute Febrile illness Fetal infections Abnormal placentation
Pneumonia/asthma Placental abruptio
Epilepsy Oligo/poly-hydromnious

9. Intermittent Auscultation
• Assessment includes baseline FHR, rhythm (regular or irregular), and
the presence or absence of accelerations or decelerations.
• Frequency:
• Every 30 minutes
• Every 15 to 30 minutes in the active phase
• Every 15 minutes in the second stage before pushing
• Every 5 minutes in the second stage when pushing
• Method
• Palpate the maternal abdomen to identify fetal presentation and position.
• Place the Pinard, fetoscope or Doppler over the area of maximum intensity of
the fetal heart sounds (usually over the fetal back).
• Place a finger on the mother's radial pulse to differentiate maternal from FHR.
To determine a baseline rate auscultate for 1 full minute between
contractions.
• A baseline rate determined by IA is written as a single number, not a range.

10. Electronic fetal Monitoring-CTG
• CTG provides continuous indicators of foetal wellbeing Useful for
monitoring foetal condition during distress i.e. Labour, decreased oxygen
availability/decreased heart rate
• Initially expected to reduce the incidence
• Foetal death during labour
• Reduction in cerebral palsy and the rate of seizures in the newborn

11. Interpreting CTG
• Interpretation of a CTG tracing requires both qualitative and
quantitative description of:
• Uterine activity (frequency, duration, intensity of contractions and resting
tone)
• Baseline fetal heart rate (FHR)
• Baseline FHR variability
• Presence of accelerations
• Periodic or episodic decelerations
• Changes or trends of FHR patterns over time.

12. • The baseline rate (BR) is between • 110 and 160 beats/minute
• Normal variation 5 to 25 bpm
• Accelerations: A rise in FHR of 15 bpm above the baseline that is
sustained for more than 15 seconds.
• Decelerations: Transient fall in fetal heart rate of 15 bpm for 15s or
more. >60s: prolonged deceleration
4 types: Early, Variable, Atypical and Late

14. Fetal scalp sampling
• Fetal scalp sampling should be performed when indicated in the presence of atypical
(non-reassuring) FHR patterns that are not responsive to intrauterine resuscitation.
The following thresholds should be used when interpreting fetal scalp pH.
• pH 7.25 FSS should be repeated if the FHR abnormality persists.
• pH 7.21– 7.24 Repeat within 30 minutes or consider delivery if rapid fall since last sample.
• pH 7.20 Expedite delivery.
Limitations
Provides only instantaneous, and not continuous, information; repeat sampling may be
necessary.
Technical limitations: operator skill, maternal discomfort, requires cervix to be at least 2
cm dilated, sample contamination with amniotic fluid.
May be normal in early stages of metabolic acidosis because it takes time before hydrogen
ions produced in peripheral tissue to cross to the blood stream.
• Contraindications Known or suspected fetal blood dyscrasia (hemophilia, von
Willebrand’s). Active maternal infection (HIV, genital herpes)

15. Fetal scalp sampling cont’d
• Limitations
• Provides only instantaneous, and not continuous, information; repeat
sampling may be necessary.
• Technical limitations: operator skill, maternal discomfort, requires cervix to be
at least 2 cm dilated, sample contamination with amniotic fluid.
• May be normal in early stages of metabolic acidosis because it takes time
before hydrogen ions produced in peripheral tissue to cross to the blood
stream.
• Contraindications:
• Known or suspected fetal blood dyscrasia (hemophilia, von Willebrand’s).
Active maternal infection (HIV, genital herpes).

16. Management of abnormal fetal heart rate by
intermittent auscultation
>160/min for
>10 min
<110 for
> 10 min

17. Intrauterine resuscitation
• In cases of suspected intrauterine hypoxia-acidosis, intrauterine
resuscitation should be undertaken immediately.
• Simultaneously and with the help of labour companions and other
health care providers:
• Call for help.
• Explain the situation to the woman and her family.
• Ask or help the woman to move to the lateral position. Maternal
repositioning will often improve uterine blood flow and may
relieve cord compression.
• Increase fluid load to correct hypotension or hypovolemia.

18. Intrauterine resuscitation
• Increase maternal oxygen saturation
• - Give oxygen if available.
• - Modify breathing techniques to improve oxygen saturation. –
• Modify pushing techniques i.e. encourage woman to breathe through
contractions rather than hold her breath for prolonged periods.
• Stop oxytocin administration.
• Perform vaginal examination: - Exclude cord prolapse - Assess cervical
dilatation:
• • Estimate duration of remaining labour to assist in determination of
best course of action.
• • If cervix fully dilated, perform operative vaginal delivery, if safely
feasible.

19. References
• Liston R, Crane J, Hughes O, Kuling S, MacKinnon C, Milne K,
Richardson B, Trépanier MJ; Fetal Health Surveillance in Labour. J
Obstetrics Gynaecology Canada. 2002 Apr;24(4):342-55