Indications
- Post-dates (41+0 weeks and beyond), hypertensive disorders, diabetes, growth restriction, prelabour rupture of membranes at term, oligohydramnios, cholestasis, reduced movements with concern, twins at term, maternal request after discussion (the ARRIVE trial at 39 weeks).
- Contraindications: placenta praevia, vasa praevia, transverse lie, cord presentation, prior classical caesarean, active genital herpes, invasive cervical cancer. Prior low transverse caesarean is a relative caution: mechanical methods and oxytocin, not prostaglandins.
The Bishop score
| Component | 0 | 1 | 2 | 3 |
|---|---|---|---|---|
| Dilatation (cm) | Closed | 1 to 2 | 3 to 4 | 5 or more |
| Effacement (percent) | 0 to 30 | 40 to 50 | 60 to 70 | 80 or more |
| Station | minus 3 | minus 2 | minus 1 or 0 | plus 1 or 2 |
| Consistency | Firm | Medium | Soft | |
| Position | Posterior | Mid | Anterior |
A score of 6 or less is unfavourable and needs ripening; 8 or more behaves like spontaneous labour.
Methods
- 1
Ripening, unfavourable cervix
Prostaglandins (vaginal dinoprostone insert or gel; oral or vaginal misoprostol in low doses) or a mechanical balloon catheter. The balloon has less tachysystole and is preferred after a prior caesarean.
- 2
Amniotomy
Once the cervix allows, with the head applied to it (a high head risks cord prolapse). Note the liquor colour and the fetal heart rate afterwards.
- 3
Oxytocin
Titrated infusion until contractions are adequate (3 to 4 in 10 minutes), with continuous monitoring. Tachysystole with fetal heart rate changes: reduce or stop, reposition, consider terbutaline.
- 4
Membrane sweep
Offered from 39 weeks; reduces the need for formal induction.
Check
Induction at 41+2 weeks, Bishop 3, one prior low transverse caesarean. Which ripening method?
On the modelCervixIsthmus and lower segment