Foetal Monitoring Flashcards
Give 5 factors that may make women high-risk in labour
- Maternal/ medical history
- Obstetric history
- History of pregnancy/ foetal history
- Presenting factor
- Features of labour
Describe intermittent auscultation
- Low-risk women
- Do not require admission CTG
- 1st stage = auscultate every 15 mins after most recent contraction for min. 60s
- 2nd stage = auscultate every 5 mins after most recent contraction for min. 60s
- If abnormalities are noted, commence continuous monitoring
What do NICE guidelines say regarding intermittent auscultation?
- Do not offer CTG to women at low risk of complications
- Use Pinard or Doppler ultrasound
- Record accelerations and decelerations
- Palpate maternal pulse if foetal HR is abnormal to differentiate between HRs
Give some pregnancy indications that continuous electronic foetal monitoring (cEFM) is required
- Previous CS
- Pre-eclampsia
- Pregnancy >42 wks
- Induced labour
- Diabetes
- Prematurity
- Oligohydramnios
- Multiple pregnancy
- Breech
What is oligohydramnios?
Deficiency of amniotic fluid
Give some labour indications that cEFM is required
- Pulse >120bpm
- BP >160/ or >/110
- BP 2x >140/ or >/90 in 30 mins (or 2+ protein in urine and >140/90)
- Oxytocin use
- Significant meconium
- Vaginal bleeding
What is a tocograph?
A pressure monitor that records uterine activity continuously
What is an ultrasound transducer?
Records the foetal heart by transmitting ultrasound waves which are then bounced off a moving object (the valves of the heart)
Name a method of internal foetal monitoring
Foetal scalp electrode
What does monitoring help prevent?
- Hypoxic Ischaemic Encephalopathy (brain injury caused by oxygen deprivation)
- Neonatal seizures
- Cerebral palsy
- Intrapartum death
How should monitoring be prepared?
- Paper speed 1cm/min
- Date and time correct
- FHR displays 50-210 used
- Tocograph basline set
- Date, time and woman’s name and number written on trace
- Maternal pulse palpated simultaneously with auscultation and recorded
- Palpate, measure, pinard
Give some limitations and adverse effects of foetal monitoring
- No evidence to support it
- High false positive rate (40-60%)
- Expensive
- Increases risk of intervention and operative delivery
- Parental anxiety
What are the 3 groups of babies that can be classified by foetal monitoring?
- OK - coping well with stress of labour
- Showing stress response but coping
- Not coping with stress response
What does the anagram MOTHERS refer to?
M - meconium O - oxytocin T - temperature H - hyperstimulation/ haemorrhage E - epidural R - rate of progress S - scar (previous CS)
What is significant meconium?
Green = sign of foetal distress
What does the anagram DR C BRAVADO refer to?
DR - define risk (high/low)
C - contractions (present, frequency, strength)
Bra - baseline rate (normal, bradycardia, tachycardia)
V - variability (>5bpm)
A - accelerations
D - decelerations (early, variable, late, prolonged)
O - overall (normal, suspicious, pathological) and plan
What are the 4 features that should be documented from a CTG?
- Baseline FHR
- Baseline variability
- Presence/absence of decelerations
- Presence of accelerations
What happens if the CTG cannot be interpreted?
Senior obstetric input is required
What is the baseline rate?
- Mean level of FHR over 10-15 minutes without accelerations/decelerations
- Balance between SNS and PNS
What are the 3 categories of baseline rate defined by the NICE?
- Reassuring = 110-160bpm
- Non-reassuring = 100-109 or 161-180bpm
- Abnormal = >180 or <100bpm
Give some factors that may cause an abnormal bradycardia baseline
- Maternal hypotension (low BP)
- Hypertonic uterus (too many contractions
- Placental abruption
- Rapid progress
- Hypoxia
- Cord prolapse
Give some factors that may cause an abnormal tachycardia baseline
- Prematurity
- Foetal movements
- Hypoxia
- Foetal anaemia or hypovolaemia
- Maternal pyrexia/ tachycardia
- Drugs = Ritodrine, Ventolin, Nicotine
What is baseline variability?
The degree that the baseline varies in a particular band width, excluding accelerations and decelerations (5-25bpm)
- Determined between contractions
- Normal for foetus to have periods of reduced variability
What are the 3 classifications of baseline variability defined by the NICE?
- Reassuring - 5-25bpm
- Non-Reassuring - <5bpm for 30-50 mins or >25bpm for 15-25 mins
- Abnormal - <5bpm for over 50 mins or >25bpm for over 25 mins or sinusoidal (constant HR - linked with thumb sucking)
What is the most important marker of foetal wellbeing?
Baseline variability >5bpm
Intact CNS
Give some factors that may cause reduced variability
- Paper speeds
- Sleep phase
- Prematurity
- Tachycardia
- Congenital malformations
- Drugs (pethidine, sedatives, anti-hypertensives, anti-epileptics)
Describe accelerations
- Increase above baseline rate of 15bpm+ lasting 15 seconds+
- Presence is reassuring but absence is not necessarily concerning
- There should always be accelerations antenatally
What are decelerations?
Slowing of FHR below baseline of 15bpm+ lasting 15 seconds+
- If variability is abnormal, decelerations may be significant even if drop is <15bpm/ shallow
What are the 4 types of deceleration?
- Early - very rarely <2% benign, nadir of deceleration matches peak of contraction, late 1st + 2nd stage
- Late - nadir 20 seconds after peak of contraction
- Variable - most common (85%), variable in shape, length, depth and frequency
- Prolonged - 3 minutes+
What causes early decelerations?
Head compression
What causes late decelerations?
- Placental insufficiency
- Hypoxia
What causes variable decelerations?
Cord compression
What causes prolonged decelerations?
- Hypoxia
- Tachysystole
- Hypotension
- Ruptured uterus
- Cord prolapse
- VE
- Spontaneous rupture of membranes
- FBS (foetal blood sampling)
What are decelerations caused by?
High BP or acidic blood
What are the 2 main baroreceptors?
Carotid sinus
Aortic arch
How do baroreceptors react to high BP?
- Head and cord compression causes increased BP
- Baroreceptor stimulated
- Parasympathetic NS stimulated
- AVN slowed via vagus nerve
- FHR slows down
What are the 3 main chemoreceptors
Carotid body
Aortic arch
Brain
How do chemoreceptors react to acidic blood?
- Increase in H+ ions and carbon dioxide and low PO2
- Parasympathetic NS stimulated
- Decreased FHR
- Until H+ and CO2 are rinsed from foetal circulation, FHR will remain low
What are the 3 classifications of deceleration?
- Reassuring
- Non-reassuring
- Abnormal
Describe a reassuring deceleration
- No decelerations
- Variable decelerations with no CC for <90 mins
Describe a non-reassuring deceleration
- Variable decelerations with no CC for >90mins
- Variable decelerations with CC with <50% contractions for >30mins
- Variable decelerations with CC with >50% contractions for <30mins
- Late decelerations with >50% contractions and <30mins
Describe an abnormal deceleration
- Variable decelerations with CC with >50% contractions for >30mins
- Late decelerations with >50% contractions and >30mins or <30mins with maternal/foetal risk factors
- Prolonged decelerations >3mins
What does CC stand for?
Concerning characteristics
What are the 4 categories that are defined by foetal monitoring?
- Normal (all features reassuring)
- Suspicious (1 non-reassuring feature and 2 reassuring features)
- Pathological (1 pathological feature OR 2 non-reassuring features
- Need for Urgent Intervention (acute bradycardia or a single prolonged deceleration)
What is the appropriate timeline for a foetus in need of urgent intervention?
3 mins = call obstetrician 6 mins = obstetrician present, thinking about theatre 9 mins = in theatre 12 mins = knife to skin 15 mins = baby born
Describe the management for the ‘normal’ category
- Continue CTG if high risk
- Discontinue if CTG commenced due to concerns arising from intermittent auscultation
- Discuss progress with woman
Describe the management for the ‘suspicious’ category
- Correct underlying cause
- Maternal obs
- Start conservative measures
- Inform senior midwife/ obstetrician
- Document plan for CTG review and clinical picture
- Discuss progress with woman
Describe the management for the ‘pathological’ category
- Obtain review by senior midwife and obstetrician
- Exclude acute events
- Correct underlying causes
- Start conservative measures
- Discuss progress with woman
What should be done if CTG remains pathological after implementing conservative measures?
- Further review by obstetrician
- Offer digital foetal scalp stimulation and document outcome
What should be done if CTG is still pathological after foetal scalp stimulation?
- Consider FBS
- Consider expediting (speeding up) birth
- Take woman’s preferences into account
Describe the management for the ‘need for urgent intervention’ category
- Urgently seek obstetric help
- Expedite birth if there has been acute event
- Correct underlying causes
- Start conservative measures
- Prepare for urgent birth
- Discuss progress with woman
- Expedite birth if acute bradycardia persists for 9mins
- If FHR recovers before 9mins, reassess decisions to expedite birth and discuss with woman
Give 2 examples of underlying causes
Hypotension
Hyperstimulation
Give 3 examples of acute events
Cord prolapse
Placental abruption
Uterine rupture
Give 4 examples of conservative measures
Fluids
Reduce/stop oxytocic
Change position
Offer tocolytic drugs (e.g. terbutaline 0.25mg)
What are the NICE guidelines regarding general care during foetal monitoring?
- Make documented systematic assessment of condition of woman and baby every hour, or more frequently if concerned
- Do not make decisions based on CTG alone
- Focus care on woman, not CTG
- Consider woman’s preferences
- Provide one-to-one support
- Maintain communication with woman and family
Describe how foetal monitoring information should be stored and documented
- Check date/time on EFM machine
- Note all events
- ‘Fresh eyes’ hourly - trace should be seen, reviewed and a plan made by 2 staff members
- Sign trace and record date, time and mode of birth
- Store records securely
