Haidl 2020.

Study characteristics
Methods	Prospective randomised controlled study
Participants	Setting: recruited from Akershus University Hospital, Norway Sample size: N = 151 Participants: age 29.8 ± 4.3 years (BI) and 30.4 ± 4.1 years (AMB) Inclusion criteria: Adult women, ASA<3, singleton term pregnancy (gestation >37 weeks), maximum of one previous delivery.  Exclusion/ criteria: Poor communication skills in Norwegian or English, height <150cm, pre‐eclampsia, contraindication to epidural. 1 women in BI group excluded after randomisation ‐ withdrew consent.
Interventions	AMB (n = 75): 0.1% bupivacaine + fentanyl 2 µg/mL at 5 mL every 60 minutes following a 10 mL loading dose. First bolus administered 15 minutes after loading dose. PCEA (5 mL, lockout 20 minutes) allowed, breakthrough pain despite PCEA managed with a physician‐administered epidural bolus. BI (n = 75): 0.1% bupivacaine + fentanyl 2 µg/mL at 5 mL/h infusion following a 10 mL loading dose. Infusion started 15 minutes after loading dose. PCEA (5 mL, lockout 20 minutes) allowed, breakthrough pain despite PCEA managed with a physician‐administered epidural bolus.
Outcomes	LA consumption Number of participants needing physician intervention Duration of treatment Mode of delivery Overall satisfaction Motor block
Notes	Study dates: March 2017 to September 2018 Funding sources not declared No conflict of interests declared
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation by computer generated algorithm: Quote:"The group assignment was determined by a computer generated algorithm"
Allocation concealment (selection bias)	Unclear risk	Allocation concealment via sealed envelopes, but it was not stated if envelopes were opaque: Quote:"...and kept in individual sealed envelopes until patients were included."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants were blinded, but the anaesthetist was not blinded: Quote:"All participants and study personnel assessing patients were blinded to the intervention. The anesthetist including the patient, and starting the treatment, was not blinded to the intervention."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessors were blinded: Quote:"All participants and study personnel assessing patients were blinded to the intervention."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low attrition: only 1 patient was excluded after randomisation
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	Appears to be free of other sources of bias.