Consultation

1
Consultation Fetal Distress in Labour

• Max Brinsmead PhD FRANZCOG
• March 2010

2
You are the obstetrician on call for labour ward
when this CTG arrives by fax.
3
A CTG arrives from labour ward

• Analyse and classify this CTG
• What is the degree of urgency that requires your
  further evaluation of this patient
• What further information do you require
• About this patient?
• About the resources available to you

4
A CTG arrives from labour ward

• Baseline FHR
• Possibly 140 bpm at the beginning and probably
  150 at the end of this recording
• Short term variability 5 bpm
• Within normal limits but not totally reassuring
• There are no accelerations present
• Atypical variable decelerations
• With most contractions, to a depth of 100 bpm
  with onset, nadir and recovery gt20sec beyond the
  contractions and lasting up to 2 minutes
• Tocographic evidence of excessive uterine
  activity
• This is a pathological CTG (RCOG 2007
  classification)

5
Further information required

• Are there any risk factors for fetal hypoxaemia
• Any other signs of fetal distress
• The stage of labour
• The experience of the person caring for this
  patient
• Access to scalp sampling
• Access to theatre
• Paediatric resources

6
Further information required

• Are there any risk factors for fetal hypoxaemia
• Any other signs of fetal distress
• The stage of labour
• The experience of the person caring for this
  patient
• Access to scalp sampling
• Access to theatre
• Paediatric resources

• Nullipara at 41.5w undergoing induction of labour
  after a normal pregnancy
• No liquor with attempted amniotomy. Oxytocin 12
  mU/min
• 3 cm dilated and 50 effaced
• In the care of a midwife
• No scalp sampling available
• Theatre doing an orthopaedic case
• Specialist paediatrician on call. Level 2 nursery

7
List and discuss the causes of fetal heart rate
decelerations

• Maternal hypotension
• Cord prolapse and compression
• Uterine hypercontractility
• Uteroplacental insufficiency
• Maternal drugs
• Acute events
• Second stage labour

8
List and discuss the causes of fetal heart rate
decelerations

• Maternal hypotension

• Can be caused by supine position, epidural
  anaesthesia or drugs that lower BP
• Correct by rolling the patient on her side and
  provide IV fluids by rapid infusion
• Adrenergic agents are sometimes used by
  anaesthetists to correct spinal hypotension

9
List and discuss the causes of fetal heart rate
decelerations

• Cord prolapse and compression

• Cord prolapse occurs with prematurity, high
  presenting part or malpresenation
• Cord compression occurs with oligohydramnios /-
  IUGR
• May be recognised in its early stages by an
  acceleration deceleration-type CTG or variable
  decelerations
• Immediate VE to exclude obvious cord presentation
  or prolapse is desirable

10
List and discuss the causes of fetal heart rate
decelerations

• Uterine hypercontractility

• Occurs in up to 40 of labours stimulated with
  oxytocin gt12 mU/min
• May be due to a high baseline tone, frequent or
  prolonged contractions
• Is difficult to diagnose using external
  tocography
• Takes up to 45 minutes to recover after cessation
  of oxytocin
• Can also occur after vaginal or oral
  prostaglandins and spontaneously in a few
  multigravida

11
List and discuss the causes of fetal heart rate
decelerations

• Uteroplacental insufficiency

• Usually associated with a pregnancy at risk e.g.
  hypertension, small for dates, smoking, recurrent
  APH etc.
• Classically causes late decelerations
• May be compounded by cord compression with
  oligohydramnios
• So severe variable decelerations or other CTG
  signs of fetal acidosis such as tachycardia or
  reduced short term variability may occur

12
List and discuss the causes of fetal heart rate
decelerations

• Maternal drugs

• Sedative drugs and narcotics cause reduced short
  term variability rather than decelerations
• But a bolus of local anaesthetic reaching the
  fetal myocardium can cause bradycardia
• And this can occur with paracervical block and
  sometimes epidural anaesthesia

13
List and discuss the causes of fetal heart rate
decelerations

• Acute events e.g.
• Placental abruption
• Uterine rupture
• Fetal haemorrhage
• Maternal collapse from eclampsia, embolism, high
  spinal etc.

• Usually associated with profound and prolonged
  bradycardia
• Abruption usually associated with PV bleeding
• Dark bleeding from vasa previa can be tested for
  fetal haemoglobin
• Uterine rupture practically never occurs in a
  nulliparous patient
• Maternal collapse usually self evident when
  priority should be given to maternal resuscitation

14
List and discuss the causes of fetal heart rate
decelerations

• Second stage labour

• Decelerations are common in the second stage of
  labour
• Due to head compression /- any contribution from
  cord entanglement compression
• The depth and width of decelerations, recovery
  after dips and nature of any interval CTG is
  helpful in assessment
• Plus the clinical background more likely to be
  significant in the fetus at risk

15
You assess this patient 12 min later. Oxytocin
infusion has ceased. There is no improvement in
the CTG. The midwife reports fresh meconium. What
do you do next? Why?

• Reassure the patient
• Quickly evaluate any antenatal record that is
  available
• Perform abdominal and vaginal examination
• Attach a scalp clip
• Reassure the patient

16
You assess this patient 12 min later. Oxytocin
infusion has ceased. There is no improvement in
the CTG. The midwife reports fresh meconium. What
do you do next? Why?

• Reassure the patient

• Maternal anxiety reduces uterine perfusion
• It is desirable to quickly establish rapport and
  cooperation with the patient
• It is also desirable to strengthen team
  performance by taking charge

17
You assess this patient 12 min later. Oxytocin
infusion has ceased. There is no improvement in
the CTG. The midwife reports fresh meconium. What
do you do next? Why?

• Quickly evaluate the AN record (if possible)

• If all the information is readily available in a
  format familiar to you then you can quickly look
  for risk factors for fetal hypoxia
• Assists is interpreting the CTG and assessing
  fetal reserve
• Provides cues that may assist in patient
  communication or cooperation e.g. first name,
  age, status, history of sexual abuse etc.
• Any contraindication to scalp clip such as HIV?

18
You assess this patient 12 min later. Oxytocin
infusion has ceased. There is no improvement in
the CTG. The midwife reports fresh meconium. What
do you do next? Why?

• Perform abdominal and vaginal examination
• Attach a scalp clip

• Requires removal of abdominal straps
• Exclude abruption, assess fetal size, position
  and how much head is palpable in the hope that
  immediate assisted delivery may be possible
• Exclude cord prolapse and presentation, assess
  stage of labour and how fast the process is going
• A scalp clip is the best method of FHR assessment
• And an acceleratory response to this trauma would
  be reassuring

19
No antenatal records available. Mother anxious
but cooperative. Uterus NAD relaxing. EFW
average. Head 2/5 palpable, back to the left. Cx
4 cm effaced. Head at spines -1, LOT. No FH
response to scalp clip attachment. CTG
deteriorating wider deeper decelerations
variability lt5 bpm

• What is the positive predictive value of this CTG
  for fetal acidosis
• What would be the optimal management of this
  patient

20
No antenatal records available. Mother anxious
but cooperative. Uterus NAD relaxing. EFW
average. Head 2/5 palpable, back to the left. Cx
4 cm effaced. Head at spines -1, LOT. No FH
response to scalp clip attachment. CTG
deteriorating wider deeper decelerations
variability lt5 bpm

• What is the positive predictive value of this CTG
  for fetal hypoxia
• What would be the optimal management of this
  patient

• With the exception of a pre terminal CTG this
  test has no better than 50 PPV for fetal
  hypoxia and acidosis
• Fetal scalp sampling for pH or lactate. Lactate
  requires a smaller blood sample, cheaper more
  robust equipment is less prone to interference
  from exposure to air

21
There are no facilities for scalp sampling. You
cannot access a theatre for Caesarean for 45 60
minutes. List and discuss the pros and cons of
the various options for intrauterine
resuscitation that you may consider in the
interim.

• Maternal oxygen administration
• Uterine tocolysis
• IV Fluids
• Betamimetic drugs
• Nitroglycerin or Nifedipine
• Amnioinfusion

22
There are no facilities for scalp sampling. You
cannot access a theatre for Caesarean for 45 60
minutes. List and discuss the pros and cons of
the various options for intrauterine
resuscitation that you may consider in the
interim.

• Maternal oxygen administration

• Administration in short bursts (up to 10 min) has
  been shown by fetal oximetry to improve fetal
  oxygenation
• But animal studies suggest that it can be
  detrimental in the longer term because it causes
  uterine vasoconstriction

23
There are no facilities for scalp sampling. You
cannot access a theatre for Caesarean for 45 60
minutes. List and discuss the pros and cons of
the various options for intrauterine
resuscitation that you may consider in the
interim.

• Uterine tocolysis
• IV Fluids
• Betamimetic drugs
• Nitroglycerin or Nifedipine

• The rapid IV infusion of 250 500 ml of
  crystalloid causes 20 min of uterine diastole.
  This can be useful esp. if maternal hypotension
  is contributing to reduced uterine perfusion
• RCTs of intrauterine resuscitation with
  betamimetics demonstrate improved neonatal
  outcomes without significant maternal risk
• Anecdotal reports suggest sublingual
  nitroglycerin and nifedepine can be similar

24
There are no facilities for scalp sampling. You
cannot access a theatre for Caesarean for 45 60
minutes. List and discuss the pros and cons of
the various options for intrauterine
resuscitation that you may consider in the
interim.

• RCTs of amnioinfusion for meconium or suspected
  cord compression show improved CTGs, reduced
  rates of CS and improved neonatal outcomes
• But these are restricted to settings without
  standard peripartum surveillance
• No effect on overall perinatal mortality has been
  demonstrated
• And maternal risks remain incompletely explored

• Amnioinfusion