🔑 Key Learning

  • IOL is offered when risks of continuing pregnancy outweigh those of delivery.
  • Bishop score helps assess cervical favourability.
  • Dinoprostone is used for unfavourable cervix (score ≤6); ARM + oxytocin for favourable (score >6).
  • Main risks include uterine hyperstimulation and foetal distress.

📌 Indications for Induction

Induction of labour is offered when the risks of continuing pregnancy outweigh the risks of delivery. Common indications include:

  • Post-term pregnancy (offer IOL between 41+0 and 42+0 weeks)
  • Pre-labour rupture of membranes (PROM)
  • Gestational hypertension or pre-eclampsia
  • Foetal growth restriction
  • Maternal comorbidities (e.g. diabetes, CKD)

📏 Bishop Score

Used to assess cervical readiness and predict likelihood of successful IOL. It includes:

  • Cervical dilation
  • Effacement (length)
  • Station
  • Consistency
  • Position

Score interpretation:

  • ≤6 = Unfavourable cervix (requires prostaglandin)
  • >6 = Favourable cervix (proceed to ARM + oxytocin)

🧪 Methods of Induction

Membrane Sweep

  • Inserting a finger into the cervix to separate the amniotic membranes from the lower uterine segment. Stimulates prostaglandin release, which can initiate labour within 48 hours.

Dinoprostone (PGE2)

  • Used if Bishop score ≤6
  • Administered as vaginal gel, tablet, or slow-release pessary
  • Softens and dilates cervix

Amniotomy (ARM) + IV Oxytocin

  • Used if Bishop score >6 (favourable cervix)
  • Artificial rupture of membranes followed by oxytocin to initiate contractions

⚠️ Complications

  • Uterine hyperstimulation
  • Foetal distress
  • Failed induction → emergency caesarean
  • Increased risk of instrumental delivery

📝 Exam Clues & Clinchers

  • Post-dates pregnancy: Offer induction between 41+0 and 42+0 weeks
  • Bishop Score ≤6 → prostaglandin (dinoprostone)
  • Bishop Score >6 → amniotomy and oxytocin
  • Membrane sweep can reduce need for formal IOL and may initiate labour

🔗 Useful Links and References

  • Inducing labour. NICE guideline [NG207]Published: 04 November 2021. Available here.