COMET 2001a.

Methods	Randomisation: using a customised randomisation programme provided by clinical trials experts. Blinding: participant not blinded. Assessor only blinded with respect to obstetric management. Criteria for rescue: in the traditional 0.25% bupivacaine (higher‐dose) group rescue given as fentanyl 50 µg or more concentrated bupivacaine. For CSE and low‐dose infusion (0.1% bupivacaine = fentanyl 2 µg/mL) a further 10 mL of this solution was used or 0.25% bupivacaine if necessary. Statistical analysis was performed on an intention‐to‐treat basis. Separate comparisons between mobile techniques and traditional group.
Participants	Inclusions: 1054 nulliparous women in labour. Exclusions: contraindication to epidural analgesia, previous epidural or spinal procedure, imminent delivery, injection of pethidine within the previous 4 hours. No. lost to follow‐up (post partum interview): 13.
Interventions	Epidural (n = 353): test dose 3 mL 2% lidocaine (60 mg) followed after 5 min with 10 mL bupivacaine 0.25%. Subsequent boluses of 10 mL bupivacaine 0.25% on request. Low‐dose infusion (n = 350): bolus of 15 mL bupivacaine 0.1% with fentanyl 2 µg/mL, followed by an infusion of the same at 10 mL/hr. CSE (n = 351): single space, needle‐through‐needle, sitting or lateral position. IT injection of 2.5 mg bupivacaine + fentanyl 25 µg. Then epidural boluses of 15 mL bupivacaine 0.1% + fentanyl 2 µg/mL on request.
Outcomes	Primary outcome measure mode of delivery. Secondary outcomes progress of labour (duration of first and second stages), oxytocin augmentation, regular pain assessments (VAS), women's perceptions of their ability to push and urinary retention. Neonatal assessments of Apgar scores at 1 and 5 min, resuscitation requirements and admission to the special care unit. Birthweight was recorded after delivery.
Notes	UK. Funded by grants from the NHS Research and Development Mother and Child Health Programme.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Used a customised randomisation programme.
Allocation concealment (selection bias)	Low risk	The study group code was not revealed before completion of recruitment.
Blinding (performance bias and detection bias) All outcomes	High risk	The participants and those in attendance were not blinded. Trial midwives assessing VAS 24 hours after delivery were blinded to obstetric management.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Total number lost 13 (of 1054 randomised).
Selective reporting (reporting bias)	Low risk	Primary and secondary outcomes were reported.
Other bias	Low risk	No other bias evident.