Management of Labour and Delivery

Question 1

Describe the 1st stage of labour.

Answer 1

• Onset of labour, until the cervix of fully dilated.
  
  • Latent: painful contractions, where there is some cervical effacement and dilatation up to 4cm.
  • Established: painful contractions and progessive cervical dilatation from 4cm.

Question 2

Describe the 2nd stage of labour.

Answer 2

• From full cervical dilation, until the baby / baby head is delivered.

Question 3

Describe the 3rd stage of labour.

Answer 3

• From delivery of the baby, until delivery of the placenta and membranes.

Question 4

Describe the observations made using a partogram.

Answer 4

• Graphical display of intrapartum information.
• Allows for assessment of the:
  
  • Power
    
    • Frequency and duration of contractions
    • Strength - remains subjective
  • Passenger
    
    • Foetal heart monitoring
    • Position / station / moulding / caput
  • Passage
    
    • Effacement and dilation of the cervix
• Commence following accurate diagnosis of established labour
  
  • Progress in labour
  • Action lines

Question 5

Explain the difference between induction and augmentation of labour.

Answer 5

• Induction of labour:
  
  • ​The process of starting labour
• Augmentation of labour:
  
  • ​Process of accelerating labour which is already underway:
    
    • Pre-Labour rupture of membranes
    • Delay in 1st / 2nd stage of labour

Question 6

What are the indications for induction or augmentation of labour?

Answer 6

• Prolonged pregnancy
  
  • In 5-10% of women pregnancies continue beyond 42 weeks.
  • Risk of perinatal death.
• Maternal DM
• Twin pregnancy
• Pre-term rupture of membranes
• Foetal growth restriction / placental insufficiency
• Hypertensive disorders
• Maternal medical disorders (renal /cardiac)
• Maternal age
• Reduced foetal movements
• Maternal request

Question 7

What are the pharmacological methods of induction of labour?

Answer 7

• Prostaglandins (PGE2)
  
  • Promote cervical ripening and stimulate uterine contraction.
  • Vaginal route has fewest side effects.
    
    • Gel / tablet / sustained release pessary.
  • Greater risk of hyperstimulation.
• Syntocinon
  
  • ‘Synthetic’ oxytocin
  • Stimulates uterine contraction
  • Only used following amniotomy
  • IV infusion / dose titration to achieve contractions 4:10

Question 8

What are the mechanical methods of inducing / augmenting labour?

Answer 8

• Membrane sweep
  
  • ​May double incidence of onset of spontaneous labour if carried out after 40/40.
• Amniotomy (ARM - artificial rupture of membranes)
  
  • ​Favourable cervix
  • Also used to augment labour
  • Allows assessment of the colour of liquor
  • More likely to require oxytocin augmentation
  • Head should be engaged or there is risk of cord prolapse.
• Other
  
  • ​Balloon
  • Laminaria tents

Question 9

Describe the cervical scoring system and how this determines which procedure should be carried out.

Answer 9

• Assess favourability of the cervix.
  
  • ​Score <8 = unfavourable cervix → ripen with PG.
  • Score 8+ = favourable cervix → proceed with amniotomy.

Question 10

What are the complications of induction and augmentation of labour?

Answer 10

• Uterine hyperstimulation (1-5%)
  
  • Foetal distress
  • Remove stimulus / role of tocolysis
• Labour experience
• Increased obstetric intervention
  
  • Epidural
  • Assisted vaginal delivery
• No increased risk of C-section
• Uterine rupture
  
  • Caution in the presence of previous uterine surgery, especially with prostaglandins
• Failure / repeat courses

Question 11

What are the methods of pain relief used during delivery?

Answer 11

• Non-pharmcological
• Pharmacological:
  
  • ​Inhaled
  • Opioid
  • Regional
• Delivery
  
  • ​Local anaesthetic
    
    • Perineal
    • Pudendal
  • Regional
  • GA

Question 12

What are the non-pharmacological methods of pain relief used in labour?

Answer 12

• Maternal support
  
  • 1:1 care in labour
    
    • Requires less analgesia, higher SVD rate, better experience in labour.
  • Birthing pools
    
    • Reduce the need for regional anaesthesia
    • Caution if the mother has had opioid analgesics
  • Breathing and relaxation techniques / accupuncture / hypnosis / massage / aromatherapy / TENS.
    
    • Limited evidence to support use.

Question 13

Describe the use of Entonox in labour.

Answer 13

• 50:50 mixture of O₂ and nitrous oxide
• Commonly used
• Not a potent analgesic
• Generally very safe to use
• Adverse effect
  
  • Nausea
  • Vomiting
  • Drowsiness
  • Light-headedness

Question 14

Describe the use of opioid analgesics in labour.

Answer 14

• Diamorphine 5-10mg
• Tend to have a limited effect during labour
• Adverse effects:
  
  • Maternal
    
    • Nausea and vomiting (administer with anti-emetic)
    • Drowsiness
  • Neonatal
    
    • Drowsiness / respiratory depression (ideally do not administer within 3-4 hours of delivery)
• Continuous IV infusion
  
  • Remifentanil
  • Short acting
  • PCA

Question 15

What are the factors involved in prescribing epidural anaesthesia during labour?

Answer 15

• Regional anaesthesia = epidural.
• More effective than parenteral opioids.
• Prolonged second stage
  
  • Increases AVD
  • No increase in lower uterine segment C-section
  • Increase in malabsorption
• Top-up
  
  • Obstetric intervention
• Side effects:
  
  • Hypotension
  • Pyrexia / pruritis

Question 16

What are the factors involved in prescribing spinal anaesthesia during labour?

Answer 16

• Regional anaesthesia = spinal.
• Predominantly used for obstetric intervention
  
  • Denser block than epidural
• Single shot injection, lasts 2-4 hours
• Side effects:
  
  • Hypotension
  • Pyrexia / pruritis
  • High block

Question 17

What are the risks associated with GA during labour?

Answer 17

• Higher risks in the pregnant population compared to the non-pregnant population.
• Tissue oedema
• Reduced gastro-oesophageal tone
• Increased intra-abdominal pressure
• Delayed gastric emptying
• Increased gastric acidity

Question 18

What is the aim of intrapartum foetal monitoring?

Answer 18

• The ultimate aim of intrapartum foetal monitoring is the prevention of death and morbidity due to hypoxia.
  
  • Hypoxaemia / hypoxia cause changes in the foetal heart rate pattern.
• Changes in the foetal heart pattern during labour are very common, but significant foetal hypoxia is relatively rare.
  
  • C-section rates tend to rise by ~30% with the use of ‘routine’ monitoring, due to over-diagnosis of foetal distress.
  • Can restrict mobility in labour.

Question 19

What factors affect the foetal heart rate?

Answer 19

• The heart has an intrinsic rate.
• Nerve supply
  
  • Rate is reduced by the vagus nerve (parasympathetic)
  • Rate is increased by the sympathetic supply
• Circulating catecholamines
  
  • Adrenal
• CNS activity
• Changes in foetal blood pressure
• Changes in foetal blood gas levels (O₂, CO₂, pH)

Question 20

Describe the use of intermittent auscultation in labour.

Answer 20

• ‘Low risk’ women in established labour.
• Doppler USS
• Performed immediately after a contraction for at least 1 minute, at least every 15 minutes.
• Recorded as a single rate, noting accelerations or decelerations if heard.
• Palpate maternal pulse.
• Act upon any changes:
  
  • Rising baseline rate
  • Decelerations
  • Assess the patient (position, hydration, contraction (frequency / tone), maternal observations).
  • Increase frequency of auscultation.
  • Continuous CTG

Question 21

What are the indications for continuous CTG monitoring in labour?

Answer 21

• Maternal tachycardia
• Maternal pyrexia
• Suspected chorioamnionitis or sepsis
• Presence of significant meconium
• Fresh vaginal bleeding
• Hypertension / proteinuria
• Confirmed delay in labour (1st or 2nd stage)
• Hypertonus or tachysystole
• Oxytocin use
• Reported pain outwith the normal
• Preterm
• Multiple pregnancy

Question 22

Describe the protocol for interpreting a CTG.

Answer 22

• Dr - determine risk
• C - contractions
• Bra - baseline rate
• V - variability
• Accelerations
• Decelerations
• Overall assessment

Question 23

What is foetal capillary blood sampling used to assess?

Answer 23

• Foetal scalp capillary sample to assess acidaemia
  
  • ​pH >7.25 - reassuring
  • pH <7.2 - nonreassuring / immediate delivery

Question 24

Why is flexion of the foetal neck important during delivery?

Answer 24

Question 25

Describe steps 1 and 2 of a normal vaginal delivery.

Answer 25

* Head in pelvic brim in left or right occipitolateral position. * Neck flexes so that the presenting diameter is suboccipitobregmatic.

Question 26

Describe steps 3 and 4 of a normal vaginal delivery.

Answer 26

* Head delivers by extension. * Descent continues and shoulders rotate into the anteroposterior diameter of the pelvis.

Question 27

Describe steps 5, 6 and 7 of a normal vaginal delivery.

Answer 27

* Head restitutes. * Anterior shoulder delivered by lateral flexion from downward pressure on the baby's head. * Posterior shoulder delivered by lateral flexion upwards.

Question 28

What is malpresentation?

Answer 28

* Malpresentation is the term used to describe any non-vertex presentation. * Face: ~1:500 * Brow: ~1:700-1500 * Breech: ~3-4% at term * Transvere lie and oblique lie: \<1% at term

Question 29

Describe face presentation.

Answer 29

* **Hyper-extension of the head.****​** * Associated with prematurity, tumours of the neck, fetal macrosomia, anencephaly. * Face is usually very swollen. * Position in relation to the chin (mento). If mento-anterior, can deliver vaginally with flexion of the neck.

Question 30

Describe brow presentation.

Answer 30

* **Presenting diameter is mento-vertical (14cm).** * Less likely to be delivered vaginally, unless head flexes during labour to become vertex presentation.

Question 31

Describe breech presentation.

Answer 31

* Associated with multiple pregnancy, bicornate uterus, fibroids, placenta praevia, polyhydramnios, oligohydramnios. * 65% - frank (extended) breech. * 35% - flexed or footing breech.

Question 32

Describe transverse lie and oblique lie.

Answer 32

* More common in multiparous women, polyhydramnios, preterm labour, fibroids, uterine anomalies, placenta praevia. * Risk of cord prolapse / limb prolapse - role of hospital confinement at term.

Question 33

What are the indications for assisted vaginal delivery?

Answer 33

* Maternal * Failure to progress in active second stage of labour. * Prim 2-3 hours * Parous - 1-2 hours * Maternal exhaustion * Foetal * Suspected foetal compromise in second stage of labour. * Pathological CTG * Abnormal FBS * Prophylactic shortening of second stage. * Hypertensive crisis * Cardiac disease * Maternal cerebrovascular disease

Question 34

What are the criteria to carry out assisted vaginal delivery?

Answer 34

* Consent / analgesia / empty bladder. * Abdominal palpation: head engaged 0/5 palpable. * Vaginal examination: cervix fully dilated, membranes ruptured, presenting part at / below ischial spines. * Position of the foetal head.

Question 35

What are the serious maternal risks associated with assisted vaginal delivery?

Answer 35

* 3rd and 4th degree perineal tear: 1-4 in 100 with vacuum-assisted delivery (common) and 8-12 in 100 with forceps delivery (very common). * Extensive or significant vaginal / vulval tear: 1 in 10 with vacuum and 1 in 5 with forceps.

Question 36

What are the serious foetal risks associated with assisted vaginal delivery?

Answer 36

* Subgaleal haematoma: 3-6 in 1000 (uncommon). * Intracranial haemorrhage: 5-15 in 10,000 (uncommon). * Facial nerve palsy (rare).

Question 37

What are the common maternal risks associated with assisted vaginal delivery?

Answer 37

* PPH: 1-4 in 10 (very common). * Vaginal tear / abrasion (very common). * Anal sphincter dysfunction / voiding dysfunction.

Question 38

What are the common foetal risks associated with assisted vaginal delivery?

Answer 38

* Forceps marks on face (very common). * Chignon / cup marking on the scalp (practially all cases of vacuum-assisted delivery). * Cephalhaematoma: 1-12 in 100 (common). * Facial or scalp lacerations: 1 in 10 (common). * Neonatal jaundice / hyperbilirubinaemia: 5-15 in 100 (common). * Retinal haemorrhage: 17-38 in 100 (very common).

Question 39

What is shoulder dystocia?

Answer 39

* Impaction of the foetal anterior shoulder behind the maternal symphysis pubis. * In practical terms: * Difficulty in delivering the shoulders, requiring additional manouvres beyond moderate axial traction. * Incidence 0.2%: * 0.5% if foetal weight \>3.5kg * 10% if foetal weight \>4.5kg

Question 40

What are the risk factors for shoulder dystocia?

Answer 40

* In \>50% cases - no risk factors * Macrosomia * DM * Postdates * Obesity * High parity * Prolonged 1st / 2nd stage * AVD

Question 41

What are the consequences of shoulder dystocia?

Answer 41

* Hypoxia * Trapped umbilical cord * pH drop ~0.04 / min * 5-7 mins = significant foetal morbidity / mortality * Nerve damage * Excessive downward traction * C5-T1 * Erb (C5-C6)

Question 42

What is the protocol for managing shoulder dystocia?

Answer 42

* **H** - Call for help * **E** - Episiotomy * **L** - Legs to McRoberts * **P** - Pressure * **E** - Enter manouvres * **R** - Remove posterior arm * **R** - Roll over

Question 43

What is a 1st degree perineal tear?

Answer 43

Injury to the perineal skin and / or vaginal mucosa.

Question 44

What is a 2nd degree perineal tear?

Answer 44

Injury to perineum involving perineal muscles but not involving the anal sphincter.

Question 45

What is a 3rd degree perineal tear?

Answer 45

* Injury to the perineum involving the anal sphincter complex: * **Grade 3a** - \<50% of external anal sphincter (EAS) thickness torn. * **Grade 3b** - \>50% of EAS thickness torn. * **Grade 3c** - Both EAS and internal anal sphincter (IAS) torn.

Question 46

What is a 4th degree perineal tear?

Answer 46

Injury to the perineum involving the anal sphincter complex (EAS and IAS) and anorectal mucosa.

Question 47

Describe episiotomy.

Answer 47

* Not routinely performed. * No clear evidence that they reduce 3rd / 4th degree tears. * Indications: * Large tear anticipated * Suspected foetal compromise * AVD * Shoulder dystocia * 'Rigid' perineum * **Anaesthesia** * Mediolateral

Question 48

What are the risk factors and prognosis for obstetric anal sphincter injury?

Answer 48

* **Risk factors** * **​**Primigravida * Foetal weight \>4kg * Shoulder dystocia * AVD * Asian ethnicity * Shortened perineum * **Prognosis** * **​**60-80% women asymptomatic after 12 months following identification and repair. * Physiotherapy * Future mode of delivery

Question 49

Describe the 4 categories of Caesarean Section.

Answer 49

1. Requiring immediate delivery. Immediate threat to the life of woman or foetus. 2. Requiring urgent delivery. Maternal or foetal compromise which is not immediately lfe-threatening. 3. Requiring early delivery. No maternal or foetal compromise. 4. Elective. At a time to suit the woman and obstetric team.

Question 50

What are the indications for caesarean section?

Answer 50

* Breech / malpresentation * Previous CS * Severe growth restriction / placental insufficiency * Placenta praevia * Suspected foetal compromise * Failure to progress in labour * Unsuccessful triad of assisted vaginal delivery * Maternal request * Past obstetric history (trauma / dystocia) * Twins

Question 51

What are the surgical considerations when performing CS?

Answer 51

* Incision * Low transverse incision / Pfannestial / Joel Cohen * Abdominal wall anatomy * Care of the bladder * Uterine incision * Delivery of the foetus * Delivery of the placenta and membranes * Repair of the uterus * Control of haemostasis * Repair of abdominal wall & closure

Question 52

What are the **serious** risks associated with CS?

Answer 52

* **Maternal** * Emergency hysterectomy (uncommon). * Need for further surgery at a later date, including curettage (uncommon). * Admission to ICU (highly dependent on reason for CS) (uncommon). * Thromboembolic disease (rare). * Bladder injury (rare). * Ureteric injury (rare). * Death (very rare). * **Future pregnancies** * Increased risk of uterine rupture during subsequent pregnancies / deliveries (uncommon). * Increased risk of antepartum stillbirth (uncommon). * Increased risk in subsequent pregnancies of placenta praevia and placenta accreta (uncommon).

Question 53

What are the **common** risks associated with CS?

Answer 53

* **Maternal** * Persistent wound and abdominal discomfort in the first few months after surgery (common). * Increased risks of repeat CS when vaginal delivery attempted in subsequent pregnancies (very common). * Readmission to hospital (common). * Haemorrhage (uncommon). * Infection (common). * **Foetal** * Lacerations (common).