Failed Induction of Labour

Failed induction of labour is failure to reach the active phase of labour (cervix 6 cm or more dilated) after a full course of cervical ripening and at least 12 to 18 hours of oxytocin with ruptured membranes. It is caused by an unripe cervix, malposition, disproportion, a poor indication or inadequate contractions. It matters because it often ends in caesarean section, and the choice between waiting, repeating and operating depends on mother and baby.

• Risk factors: first pregnancy, Bishop score below 6, body mass index above 30 kg/m2, maternal age above 35 years, short stature, large baby, post term pregnancy.
• Waiting longer with ruptured membranes raises infection risk.
• Maternal and fetal condition decide the next step.

Women have had a ripening agent and oxytocin without entering active labour, with an unripe or slowly changing cervix and contractions that may be irregular or weak. They are often tired and anxious.

• Cervix less than 6 cm dilated after hours of oxytocin.
• Fever or fetal tachycardia if membranes have been ruptured for long.
• Differential diagnosis: prolonged latent phase, inadequate contractions, cephalopelvic disproportion, occiput posterior position, chorioamnionitis, wrong gestation.
• Complications: chorioamnionitis, exhaustion, tachysystole, fetal distress, uterine rupture in scarred uterus, caesarean section, postpartum haemorrhage, neonatal sepsis.

The diagnosis is made on the partograph, after reviewing the indication and condition of mother and fetus.

• Cervical dilatation, effacement, station and Bishop score before and after each method; duration of rupture of membranes and oxytocin dose.
• Cardiotocography; maternal temperature, pulse, hydration, urine ketones.
• Ultrasound for position, estimated fetal weight, liquor volume and Doppler if growth restriction was the indication.
• Check gestation and the original indication to confirm whether it still requires birth.

The principle is to review the indication, then continue, repeat ripening after rest, or deliver by caesarean section.

• Supportive: explain the choices; rest and feeding for 12 to 24 hours if membranes are intact and mother and fetus are well; Ringer's lactate 1 litre IV over 2 hours; continuous cardiotocography on oxytocin; senior review.
• Pharmacological: repeat ripening with misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) in an unscarred uterus, or dinoprostone 10 mg vaginal insert for up to 24 hours where available; continue oxytocin 10 IU in 1 litre Ringer's lactate (10 mU/mL) started at 12 mL per hour (2 mU/minute) and doubled every 30 minutes to a maximum of 192 mL per hour (32 mU/minute) for up to 24 hours when membranes are ruptured and there is no infection; benzylpenicillin 5 million units IV then 2.5 million units 4-hourly for rupture of 18 hours or more; ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily for chorioamnionitis; cefazolin 2 g IV before caesarean section; oxytocin 10 IU IM after birth, then 20 IU in 1 litre at 125 mL per hour for 4 hours.
• Procedures: Foley catheter with a 30 mL balloon for ripening (alone or with oxytocin); amniotomy when the head is engaged; caesarean section for fetal compromise, chorioamnionitis, a strong indication to deliver, no progress after a full second course, or disproportion.
• Special groups: a uterine scar avoids misoprostol and dinoprostone and uses a Foley catheter or oxytocin with senior review; grand multiparity uses lower oxytocin rates with close monitoring; women with growth restriction or abnormal Doppler go to caesarean section sooner.
• Red flags: fever above 38 degrees Celsius, tachysystole, fetal heart rate abnormality, scar pain, bleeding, ruptured membranes for 18 hours or more.
• Follow-up: reassess every 2 to 4 hours; maternal temperature 4-hourly; newborn observation for 24 hours with sepsis screen if rupture was prolonged; review at 6 weeks.