Induction and Augmentation

Question 1

What are some indications for induction of labour?

Answer 1

• Postmaturity by 10-14 days
• Hypertensive disease/pre-eclampsia
• Diabetes
• Ruptured membranes/chorioamnionitis
• Foetal growth restriction
• Foetal compromise
• Autoimmunisation
• Placental abruption
• Twin pregnancy
• Foetal death in utero
• Termination of pregnancy
• Poor past obstetric history
• Social

Question 2

What are absolute contraindications to induction of labour?

Answer 2

• Breech presentation/transverse lie
• Placenta praevia
• Active genital herpes
• Cord presentation/prolapse

Question 3

What are the relative contraindications to inducing labour?

Answer 3

• Prematurity
• Foetal growth restriction (consider CS)
• Foetal compromise (consider CS)
• Previous CS
• Significant cephalopelvic disproportion

Question 4

What are the methods used to induce labour?

Answer 4

• Membrane stripping
• Prostin E2
• Balloon catheter
• Misoprostil
• ARM
• Syntocinon

Question 5

What score is used to predict whether induction of labour will be necessary? What comprises it?

Answer 5

• Bishop score
  
  • Cervical dilation
  • Length of cervix
  • Station of presenting part
  • Consistency of cervix
  • Position

Question 6

What are the advantages and disadvantages of using prostin E2 when considering induction of labour? Contraindications?

Answer 6

• It’s usually used to soften cervix so ARM can be performed, but often causes spontaneous IOL
• May induce uterine hyperstimulation, foetal distress (needs CTG monitoring)
• Uterine scar, ruptured membranes, foetal compromise

Question 7

What are the advantages and disadvantages of using a balloon catheter when considering induction of labour?

Answer 7

• No risk of uterine hyperstimulation
• Slow

Question 8

Why would you perform an amniotomy? What are the risks?

Answer 8

• To induce or augment (most common use for this) labour. Requires a dilated cervix
• Risk of cord prolapse if presenting part not well applied (multis, polyhydramnios). Infection, occult praevias

Question 9

Why would you use syntocinon? What are the benefits and risks?

Answer 9

• Induction of labour (generally in conjunction with prostin and ARM) via titrated IV infusion
• Short half-life
• Uterine hyperstimulation (CTG required), N/V, water intoxication, hyponatraemia (VP cross-reactivity), hypotension (only if rapidly injected)

Question 10

What are the indications for an instrumental delivery? The contraindications?

Answer 10

• Delay in the second stage of labour (exhaustion, effective epidural, malposition)
• Foetal distress in second stage of labour
• Delivery of the aftercoming head of a breech
• Maternal effort contraindicated

Contraindications

• Foetal bleeding disorders, foetal fracture predisposition, vertical HCV transmission face presentation (ventouse only)

Question 11

What is required for a successful instrumental vaginal delivery?

Answer 11

• Experience with instruments
• Fully dilated cervix
• Cephalic presentation and head engaged with position known
• Appropriate analgesia
• Lithotomy position
• Catheter passed and bladder empty
• Appropriate neonatal resuscitation facilities on standby
• Consideration of episiotomy
• If no previous successful vaginal delivery, best performed in theatre with option to continue to CS

Question 12

What are the common instruments used to deliver a baby? When are they commonly used?

Answer 12

• Forceps - delivery more likely with these but increased maternal morbidity
  
  • Neville-Barnes - used for anterior head positions
  • Kielland’s - used to rotate posterior head positions to anterior
  • Abandon if no evidence of progressive descent OR delivery not effected after 3 pulls
• Ventouse vacuum device - anterior delivery or to rotate to anterior position
  
  • Increased foetal morbidity - attempt forceps first

Question 13

What are the risks to mother and baby of an instrumental delivery?

Answer 13

• Mother
  
  • Soft tissue tears and bruising to vagina and perineum
• Baby
  
  • Superficial bruising, facial nerve palsy, intracerebral bleeding, damage to C-spine, shoulder dystocia