Failed Trial of Labour After Caesarean

Failed trial of labour after caesarean is a planned vaginal birth in a woman with an earlier caesarean section that ends in a repeat caesarean section during labour. It happens in a sizeable minority of women who attempt labour, most often for failure to progress, suspected scar rupture or fetal distress. It matters because emergency caesarean section after labour carries more haemorrhage, infection and thrombosis than planned repeat surgery.

• Risk factors for failure: induction of labour, no earlier vaginal birth, birth weight above 4000 g, body mass index above 30 kg/m2, short stature, maternal age above 35 years, earlier caesarean for failure to progress, gestation above 40 weeks.
• Scar rupture is sometimes found at operation.
• Labour ends in surgery when the scar or the fetus is at risk.

Women have labour that stalls in the first or second stage, or labour with scar pain, abnormal fetal heart rate or bleeding. Findings may include scar tenderness, a high presenting part and loss of contractions.

• Arrest of dilatation or descent despite adequate contractions.
• Sudden fetal heart rate abnormality or constant lower abdominal pain.
• Differential diagnosis: scar dehiscence, uterine rupture, placental abruption, cephalopelvic disproportion, inadequate contractions, malposition.
• Complications: haemorrhage, infection, bladder or bowel injury, adhesions, thrombosis, scar rupture, neonatal hypoxia, hysterectomy, maternal death.

The diagnosis is made when labour ends with caesarean section because of failed progress or scar or fetal concern.

• Partograph showing no progress after 4 hours of adequate contractions, or the specific indication recorded.
• Cardiotocography; assessment of scar tenderness, bleeding, pulse, blood pressure and fetal heart.
• Ultrasound for fetal position, lie and weight when in doubt.
• Examination of the scar at operation and a written record of its condition.

The principle is to recognise the failure early, avoid more oxytocin when the scar is at risk, and deliver by caesarean section with attention to haemorrhage and thrombosis.

• Supportive: stop oxytocin for scar pain or abnormal tracing; two cannulae; Ringer's lactate 1 litre IV over 1 to 2 hours; group and cross-match 2 units; anaesthetic and senior surgeon; careful inspection of the scar and the bladder at operation; bladder catheter for 12 to 24 hours.
• Pharmacological: cefazolin 2 g IV as a single dose before incision (3 g above 120 kg); oxytocin 10 IU IM after birth, then 20 IU in 1 litre Ringer's lactate at 125 mL per hour for 4 hours; tranexamic acid 1 g IV over 10 minutes at delivery; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); diclofenac 50 mg oral 8-hourly for 3 days if no contraindication; enoxaparin 40 mg subcutaneous daily for 10 days for emergency caesarean section after labour; ferrous sulphate 200 mg oral 8-hourly for 3 months if anaemic.
• Procedures: caesarean section with repair of any scar defect; hysterectomy for uncontrolled bleeding; repair of bladder injury with catheter drainage for 7 to 14 days.
• Special groups: findings of rupture or dehiscence at operation change the plan for later births to planned caesarean section at 36 to 37 weeks; HIV positive women continue tenofovir 300 mg, lamivudine 300 mg and dolutegravir 50 mg oral once daily.
• Red flags: scar rupture found at operation, bleeding above 1000 mL, bladder injury, fever above 38 degrees Celsius, wound infection, leg swelling.
• Follow-up: wound review at 1 week; haemoglobin at 24 hours; review at 6 weeks; counselling that a later birth should be planned repeat caesarean section, with an interval of at least 18 months.