OBS - Methods of Labour/Delivery

Question 1

Induction of Labour (IOL)

What is it?
Indications
Contraindications

Answer 1

1. ) What is it? - the process of starting labour artificially
   - most women undergo spontaneous labour by 42wks
   - roughly 1 in 5 pregnancies will require an induction
   - IOL is performed when it is thought that the baby will be safer delivered than remaining in utero, alternatively, maybe due to concerns about the mother’s health
2. ) Indications
   - prolonged gestation: offered between 40-42wks
   - PROM: offered >37wks or >34wks in PPROM
   - FGR/SGA (37w): 2nd most common indication
   - maternal health problems: GDM (>37w), obstetric cholestasis (>37w), pre-eclampsia, HTN
   - intrauterine fetal death if there are intact membranes: uses oral mifepristone and vaginal misoprostol
3. ) Contraindications - same as vaginal delivery
   - absolute: cephalopelvic disproportion, transverse lie, placenta/vasa praevia, cord prolapse, active primary genital herpes, previous classical C-section,
   - relative: breech presentation, triplets or higher-order, 2+ previous low transverse C-sections

Question 2

Methods of Induction

Membrane Sweep
Vaginal Prostaglandins
Amniotomy (+Oxytocin)
Cervical Ripening Balloon (CRB)

Answer 2

1.) Membrane Sweep - an adjunct to IOL
- performed to ↑ the chance of spontaneous delivery
- offered at 40/41wks to primips, 41wks for multips
- can be performed in an antenatal clinic
- insert a finger through the cervix and rotate it against the fetal membranes to help separate the chorionic
membrane from the decidua which helps to release natural prostaglandins in an attempt to kick-start labour

2. ) Vaginal Prostaglandins - the mainstay of IOL
   - ripen the cervix and help smooth muscle contraction
   - used if the bishop score is 6 or below
   - tablet (Prostin)/gel regimen: 1 cycle = 1st dose, plus a 2nd dose if labour has not started 6 hours later
   - pessary (Propess): 1 cycle = 1 dose over 24 hours
   - contraindications: ↑risk of uterine hyperstimulation, acute PID, active renal/hepatic/pulmonary/cardiac disease, fetal distress w/o imminent delivery, APH
   - failure of a cervix to ripen despite the use of prostaglandins may result in the need for a C-section
3. ) Amniotomy + Oxytocin - artificial ROM using an amnihook to release natural prostaglandins
   - used when prostaglandins are contraindicated
   - used when the bishop score is 7 and above
   - an infusion of syntocinon is often given alongside to increase the strength and frequency of contractions
   - aim is to titrate until there are 4 contractions/10mins
   - continuous CTG is needed if infusion is used, if not, use intermittent auscultation if normal HR on the CTG
4. ) Cervical Ripening Balloon - silicone balloon inserted into the cervix and inflated to dilate the cervix
   - alternative to vaginal prostaglandins when/in:
   - vaginal prostaglandins have failed
   - multips (>3) or women with a previous C-section

Question 3

Monitoring and Complications of Induction of Labour

Bishop Score
Cardiotocography (CTG)
Complications
Uterine Hyperstimulation

Answer 3

1. ) Bishop Score - pre-labour scoring system to assist in predicting whether induction of labour will be required
   - assess ‘cervical ripeness‘ based on cervical dilation, length, position and consistency, and fetal station
   - 8+/13: the cervix is ripe/’favourable’ so IOL is possible
   - <7/13: the cervix is ‘unfavourable’ and needs to ripen using vaginal prostaglandins
   - check 6hrs post tablet/gel or 24hrs after a pessary
2. ) Cardiotocography
   - must confirm a good fetal HR via a CTG prior to IOL
   - when contractions begin after IOL, assess fetal HR using continuous CTG until a normal HR is confirmed
   - subsequently, assess using intermittent auscultation
   - continuous CTG throughout labour is required if an oxytocin infusion is started (e.g. w/ amniotomy)
3. ) Complications
   - pain (more painful than spontaneous), infection
   - increased rate of intervention (C-section, forceps)
   - cord prolapse (amniotomy), failure of IOL (15%),
   - uterine hyperstimulation (1-5%), uterine rupture (rare)
4. ) Uterine Hyperstimulation - uterine contractions are prolonged and frequent –> fetal distress/compromise
   - criteria: individual uterine contractions lasting >2mins OR >5 contractions every 10 minutes
   - complications: fetal compromise w/ hypoxia and acidosis, uterine rupture, emergency C-section
   - Mx: removing the prostaglandins, stopping the oxytocin infusion, tocolysis with terbutaline

Question 4

Operative (Instrumental) Vaginal Delivery

Indications
Pre-Requisites for Instrumental Delivery
Contraindications
Classifications

Answer 4

1. ) Indications - assessed at the 2nd stage of labour
   - failure to progress (2hr for primips, 1hr for multips)
   - maternal exhaustion, fetal distress
   - control of the head in various fetal positions
   - maternal conditions e.g. intracranial pathologies, congenital heart diseases, severe HTN
2. ) Pre-Requisites for Instrumental Delivery
   - fully dilated, ruptured membranes, empty bladder
   - cephalic, defined fetal position, fetal station is 0 (head is engaged)
   - adequate maternal pelvis and pain relief
   - 1 dose of co-amoxiclav after delivery to ↓ infection
3. ) Contraindications
   - absolute: unengaged fetal head, incompletely dilated cervix, cephalo-pelvic disproportion, malpresentation (breech, face, most brow)
   - ventouse only: <34wks, fetal coagulation disorder
   - relative: acute fetal distress w/o fetal scalp visible, unengaged fetal head in second twin delivery, cord prolapse w/ fetal compromise and fully dilated cervix

4.) Classifications - based on the degree of fetal descent, higher classification means increased risks
- 1/outlet: visible fetal scalp OR fetal skull has reached the pelvic floor OR fetal head on the perineum
- 2/low: fetal station is +2 or higher, subdivided into
>45° = rotation needed, <45° = no rotation needed
- 3/midline: fetal station is between 0-2, subdivided into >45° = rotation needed, <45° = no rotation needed

Question 5

Instrument Types and Complications

Instrument Types
Ventouse
Forceps
Complications

Answer 5

1. ) Instrument Types - the ventouse or the forceps
   - choice is operator dependent, forceps has ↓risk of fetal complications but ↑risk of maternal complications
   - if after 3 contractions and pulls w/ any instrument, the attempt should be abandoned if there is no progress
2. ) Ventouse - an instrument that attaches a cup to the fetal head via a vacuum, most common systems are:
   - electrical pump attached to a silastic cup, is only suitable if the fetus is in an occipital-anterior position
   - ‘kiwi’: a hand-held, disposable device that can be used for all fetal positions, and rotational deliveries
   - during uterine contractions, traction is applied perpendicular to the cup
   - adv: less pain and less maternal perineal injuries
   - disadv: lower success rate, cephalohaematoma, subgaleal haematoma, fetal retinal haemorrhage
3. ) Forceps - double-bladed instruments, types inc:
   - Rhodes, Neville-Barnes or Simpsons: OA positions
   - Wrigley’s: C-sections, Kielland’s: rotational deliveries
   - blades are introduced into the pelvis and applied around the sides of the fetal head, gentle traction is then applied during contractions,
   - adv: doesn’t require maternal effort
   - disadv: ↑perineal tears, less often used to rotate, facial nerve palsy
4. ) Complications
   - vaginal tears/episiotomy and 3rd/4th-degree tears
   - nerve (obturator/femoral) injury, shoulder dystocia
   - PPH, infection, VTE, bowel/bladder incontinence
   - fetal trauma: scalp lacerations, skull fractures, facial nerve palsy, facial bruising, neonatal jaundice
   - fetal haemorrhage: retinal haemorrhage, subgaleal haematoma, cephalohematoma,

Question 6

Caesarean Section

Emergency C-Section
Elective (Planned) C-Section
Indications for an Elective C-Section

Answer 6

1. ) Emergency C-Section - three (four) categories
   - 1: immediate threat to the life of the mother or baby, delivery should be within 30 minutes: cord prolapse, suspected uterine rupture, major placental abruption, fetal hypoxia or fetal bradycardia (>3mins)
   - 2: maternal/fetal compromise that isn’t immediately life-threatening, should be born within 60-75 minutes
   - 3: early delivery needed but no compromise: failure to progress or a planned C-section presenting in labour
   - 4: elective C-section
2. ) Elective (Planned) C-Section
   - planned for after 39wks to reduce respiratory distress (transient tachypnoea of the newborn)
   - if done before 39wks, antenatal corticosteroids should be considered to prevent TTN
3. ) Indications for an Elective C-Section
   - previous C-section, placenta/vasa praevia
   - malpresentation: breech at term most common, others include unstable, transverse or oblique lie
   - macrosomia (>4.5kg), previous shoulder dystocia
   - symptomatic after previous 3/4th degree tear
   - twin pregnancy: 1st twin does not present cephalic
   - fetal compromise e.g. early onset FGR
   - maternal medical conditions: where labour would be dangerous for the mother (e.g. cardiomyopathy)
   - transmissible disease: HIV, genital herpes in T3
   - maternal request: various reasons, requires MDT
   - cervical cancer

Question 7

Theatre Procedure for a C-Section

Pre-Operative Preparation
Operative Procedure
Post-Operative

Answer 7

1. ) Pre-Operative Preparation
   - bloods: FBC and G+S (avg blood loss is 500ml-1L)
   - VTE risk assessment: anti-VTE stockings +/- LMWH
   - omeprazole or ranitidine +/- metoclopramide to prevent Mendelson’s syndrome (aspiration of gastric contents –> chemical pneumonitis)
   - prophylactic Abx just prior to the first incision
   - majority done under a regional anaesthetic which is usually a spinal anaesthetic or a ‘topped up’ epidural
   - sometimes done under GA e.g. in a CAT1 section

2.) Operative Procedure
- position the woman in a left lateral tilt of 15° to prevent hypotension due to aortocaval compression
- a catheter is inserted to ↓the risk of bladder injury
- the incision is a transverse lower abdominal incision,
Pfannenstiel (curved) or Joel-Cohen (straight)
- layers: skin –> SC tissue –> fascia/rectus sheath –> rectus muscle –> parietal+visceral peritoneum –> vesicouterine peritoneum –> uterus –> amniotic sac
- IV oxytocin 5IU is given to aid placental delivery

3. ) Post-Operative
   - obs recorded on an EWS, monitor PV blood loss
   - early mobilisation, eating and drinking and removal of the catheter is encouraged to enhance recovery

Question 8

Advantages and Complications of a C-Section

Advantages
Immediate Complications
Intermediate Complications
Late Complications

Answer 8

1. ) Advantages - reduced risk of:
   - perineal trauma and pain
   - urinary and anal incontinence, uterovaginal prolapse
   - late stillbirth and early neonatal infections
2. ) Immediate Complications
   - bleeding: PPH (>1L), intra-abdominal haemorrhage, wound haematoma (↑risk w/ ↑BMI, DM, immunosup…)
   - damage to local structures: bladder, bowel, ureters
   - fetal laceration, respiratory depression (TTN)
3. ) Intermediate Complications
   - infection: UTI, endometritis, respiratory infection
   - venous thromboembolism
   - ileus
4. ) Late Complications
   - adhesions, urinary tract trauma (fistula), hernias
   - subfertility: delay in conceiving
   - future pregnancies: ↑risk of stillbirth, placenta/vasa praevia, repeat C-section, scar dehiscence in VBAC
   - regret and other negative psychological sequelae
   - a caesarean scar, ectopic pregnancy

Question 9

Vaginal Birth After C-Section (VBAC)

Risks Associated with a VBAC
Contraindications of a VBAC
Advantages of a VBAC
Management of a VBAC Delivery

Answer 9

1. ) Risks Associated with a VBAC
   - increased risk of uterine rupture (0.5%)
   - increased risk of hypoxic-ischaemic encephalopathy in the neonate (HIE)
2. ) Contraindications of a VBAC
   - absolute: classical (vertical) caesarean scar, previous uterine rupture, other contraindications for vaginal birth
   - relative: complex uterine scars or >2 prior lower segment C-sections.
3. ) Advantages of a VBAC (compared to a C-section)
   - if successful, shorter hospital stay and recovery
   - If successful, better chance of future VBACs
   - reduced risk of maternal death
   - reduced risk of respiratory depression (TTN)
4. ) Management of a VBAC Delivery
   - should be delivered in a hospital setting with facilities for emergency C-section and neonatal resuscitation
   - continuous CTG monitoring
   - additional analgesic requirements during labour may indicate an impending uterine rupture
   - avoid induction (prostaglandins) and oxytocin
   - elective C-section is recommended after 39wks