Induction of Labour

Question 1

How many labours are induced?

Answer 1

10-20%

Success rate 60-80% at term

Question 2

Indications for induction

Answer 2

Uteroplacental
Insufficiency (one of the most common), Prolonged Pregnancy, IUGR, Oligo or Anhydramnios,
Abnormal CTG, PROM, Severe Pre-Eclampsia or Eclampsia after maternal stabilisation, Intrauterine Death, Antepartum Haemorrhage at term,
Chorioamnionitis; Macrosomia is a controversial indication

Question 3

Medical Indications for Induction

Answer 3

Severe HTN, Uncontrolled DM, Renal Disease or Malignancy

Question 4

Predictors for successful induction

Answer 4

Gestational Age, Parity, Bishop’s Score

Question 5

Mechanical Induction

Answer 5

Separation of Membranes from Cervix leads to Local release of Prostaglandins;
Artificial Separation (=Stretch and Sweep); 30% into Spontaneous labour <7 days, in majority
it improves Bishop score

Question 6

Prostaglandins

Answer 6

Prostaglandins (PGE2 =Dinoprostone) – Intravaginal into Posterior Fornix as gel or tablet
o CTG should be performed 30 minutes before, and after insertion to confirm wellbeing and detect Hyperstimulation; Additional doses if still not favourable after 6hrs; Multiparous seldom need more than one dose
o Oxytocin should not be started for 6hrs to avoid Uterine Hyperstimulation

Question 7

Oxytocin Infusion

Answer 7

Increases Cervical Prostaglandin levels and initiating Uterine Contractions with Myometrial receptor activation
o Best used when membranes have ruptured (either PROM or Amniotomy)
o Low dose (1-4 mIU/min); Doubled every 40 mins to achieve optimal contractions
o Continuous CTG monitoring; Sensitivity of Myometrium to Oxytocin increases during
labour, so rate needs to be revised

Question 8

Amniotomy

Answer 8

Releases Local Prostaglandins causing Cervical Ripening and Myometrial Contractions; If not initiated or no cervical changes after 2hrs, Oxytocin infusion commenced