Management of Labour Flashcards
What are the indications for induction of labour?
Prolonged pregnancy (>42 weeks) Pre-eclampsia Placental insufficiency + IUGR Antepartum haemorrhage Rhesus isoimmunisation Diabetes CKD
How can the likely outcome of induction of labour be predicted?
Assessment of the cervix –> Bishop’s score
What are the components of the Bishop’s score?
Dilatation (cm) Effacement (%) Station Cervical consistency Cervical position
How is the Bishop’s score interpreted?
Score of 0, 1, 2, or 3 for each component
Total score > 6 is strongly predictive of labour following induction
Score < 5 indicates need for cervical ripening
What are the different options for induction of labour?
Stripping of membranes (sweep)
Artificial rupture of membranes using amniotomy
Medical induction with syntocinon infusion (following amniotomy)
Medical induction + cervical ripening with prostaglandin E2 pessary
Mechanical cervical ripening (balloon catheter)
What are the requirement for undertaking artificial rupture of membranes?
Cervix - soft, effaced + at least 2cm dilated
Head should be engaged in the pelvis and should be presenting by the vertex
What is syntocinon and what are the risks of giving it?
Synthetic oxytocin
- uterine hyperstimulation (>5 contractions in 10 minutes) reduces blood flow to foetus
What are the risks of using prostaglandins for induction?
Hyperstimulation + uterine rupture
–> contraindicated in those with previous uterine scar
What is a partogram and what is included in it?
Graphic representation of maternal + foetal data during labour:
- foetal HR
- cervical dilatation
- duration of labour
- colour of liquor
- frequency + duration of contractions
- caput + moulding
- station/descent of head
- maternal HR, BP + temperature
How is the descent of the head recorded?
Station –> level of the presenting part in cm above or below the ischial spine
+1, +2 or +3 if below spines
-1, -2 or -3 if above spines
Which pain killers can be used in labour?
Opiates:
- pethidine, morphine or remifentanil
Entonox (50:50 nitrogen + oxygen) - inhaled
What are the side effects of taking opiates in labour?
Nausea + vomiting –> given with antiemetic
Foetal respiratory depression (especially if taken within 2 hours of delivery)
What are the options for regional analgesia in labour?
Epidural
Pudendal nerve block
How does an epidural work?
Fine catheter inserted into lumbar epidural space (L3-L4) and a local anaesthetic agent e.g. bupivacaine is injected
Opioid is often added to reduce the dose requirement of bupivacaine, which spares the motor fibres so women can still stand up
What are the negative effects of having an epidural during labour?
May reduce the desire to bear down + reduce uterine activity
Increased risk of assisted vaginal delivery
Abnormal foetal HR –> must monitor with CTG
Hypotension
Accidental dural puncture
Postural headache
High block –> respiratory depression
Atonic bladder
When is a pudendal block most often used?
For operative vaginal delivery
How does a pudendal block work?
Injection of local anaesthetic around nerve at the level of the ischial spine
What are the negative effects of a pudendal nerve block?
Risk of haemorrhage from pudendal artery
Risk of lignocaine toxicity if injected intravascularly
Can be ineffective
When is spinal anaesthesia used?
Operative delivery
Why is spinal anaesthesia not used for pain control in labour?
Epidural is safer + has the ability to top up with suitable doses to allow pain relief over a long period of time
How is a spinal anaesthesia performed?
Catheter placed at L3-L4 and inserted into the subarachnoid space where anaesthetic is injected
Which layers are passed through during insertion of an epidural?
Skin –> subcutaneous fat –> supraspinous ligament –> interspinous ligament –> ligamentum flavum –> epidural space
Which layers are passed through during a spinal anaesthetic?
Skin Subcutaneous fat Supraspinous ligament Interspinous ligament Liamentum flavum Dura mater Sub dural space Arachnoid mater Subarachnoid space
What is the pneumonic for interpreting CTGs?
DR - define risk C - contractions BRA - baseline rate V - variability A - accelerations D - decelerations O - overall impression
How should contractions be interpreted on the CTG?
Peaks at the bottom of the trace
–> in established labour, should be 3-5 contractions in 10 minutes
How should baseline rate be interpreted on the CTG?
Should be about 110-160bpm
- < 110 is bradycardia
- > 160 is tachycardia
How should variability be interpreted on the CTG?
Good variability is 5-15 bpm
Reduced variability is < 5bpm
Can be reduced due to foetal sleep but shouldn’t last > 40 mins
Reduced variability for > 90 minutes is abnormal
What do accelerations show on the CTG?
Rise in foetal HR for at least 15bpm lasting for > 15 seconds
Associated with foetal movements - sign that baby is healthy
Should be 2 separate accelerations every 15 minutes, occurring with contractions
What do decelerations show on the CTG?
Reductions in foetal HR by at least 15bpm for at least 15 seconds
- abnormal –> senior review
Which type of decelerations would be suggestive of foetal hypoxia?
Late (after contraction) decelerations which are slow to recover
Which two features make up a pre-terminal CTG and what is the management?
Terminal bradycardia (baseline < 100bpm for > 10 mins) Terminal deceleration (HR drops and does not recover for > 3 mins)
–> emergency C-section
Which investigation can be done if suspicious features are seen on the CTG?
Foetal scalp blood sampling (looking for acidosis)
If a pregnant women collapses and requires CPR, when should delivery of the baby be considered?
If cardiac output not restored after 3 minutes of CPR –> C-section
What should be done if the placenta has not yet been delivered 30 mins after birth of the foetus?
IM syntocinon + breastfeeding
Observe for another 30 mins (1 hour total)
What are the indications for an operative vaginal delivery?
Inadequate progress
Maternal exhaustion
Maternal medical condition that means active pushing should be limited
Suspected foetal compromise
Clinical concerns e.g. antepartum haemorrhage
What are the risks associated with ventouse delivery?
Lower success rate than forceps (but less perineal injury and less pain) Cephalhaematoma Subgaleal haematoma Foetal retinal haemorrhage
What are the risks associated with forceps delivery?
Higher rate of 3rd/4th degree tears
What are the requirements for instrumental delivery?
Fully dilated Ruptured membranes Cephalic foetal presentation Defined foetal position Foetal head at least at the level of ischial spines + no more than 1/5 palpable in abdomen Empty bladder Adequate pain relief
What are the absolute contraindications for ventouse delivery?
Preterm < 34 weeks
High likelihood of foetal coagulation disorder
What are the indications for elective C-section?
Breech or other malpresentation Twins id first twin not cephalic Maternal conditions e.g. cardiomyopathy Foetal compromise e.g. growth restriction Transmissible disease e.g. uncontrolled HIV Primary genital herpes in 3rd trimester Placenta praevia Maternal DM with foetal weight > 4.5kg Previous major shoulder dystocia Previous 3rd/4th degree tear Maternal request
Which layers are cut/torn through in a C-section?
Skin (Pfannensteil incision) Camper's fascia Scarpa's fascia Rectus sheath Rectus muscle Parietal peritoneum Visceral peritoneum Uterus (lower uterine segment)
