Fidkowski 2019.

Study characteristics
Methods	Prospective randomised single‐blind controlled study
Participants	Setting: recruited from Henry Ford Hospital, Detrot, MI, USA Sample size: N = 150 Participants: age 27.2 ± 5.5 years (BI) and 24.9 ± 4.5 years (AMB) Inclusion criteria: English speaking women at term gestation with uncomplicated pregnancies 5 women in the continuous epidural infusion group excluded: 4 reported VAPS > 10 mm 30 min after the epidural injection and one unintentional epidural catheter dislodgement during labour
Interventions	AMB (n = 43): 0.125% bupivacaine + fentanyl 2 µg/mL at 10 mL every 60 minutes following a 5 mL loading dose. First bolus administered immediately upon connection of the epidural pump. Breakthrough pain managed with a physician‐administered epidural bolus. BI (n = 34): 0.125% bupivacaine + fentanyl 2 µg/mL at 10 mL/h infusion following a 5 mL loading dose. Breakthrough pain managed with a physician‐administered epidural bolus.
Outcomes	Rate of breakthrough pain with need for anaesthetic intervention Rate of caesarean delivery Rate of instrumental delivery Duration of labour Maternal satisfaction
Notes	Excluded 3rd arm of study that received 5 mL boluses every 30 minutes. Study dates: May 2015 to July 2017 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 shuffling of opaque envelopes: quote: "Prior to enrolling the first patient, group assignments with instructions for epidural pump settings were placed in 150 opaque envelopes, 50 for each group. These envelopes were mixed and randomly placed in a container. At the time of randomization, the anesthesia provider randomly selected one of these opaque concealed envelopes to determine group randomization."
Allocation concealment (selection bias)	Unclear risk	Allocation concealment via opaque envelopes, but it was not stated if the envelopes were sealed: Quote:"group assignments with instructions for epidural pump settings were placed in 150 opaque envelopes"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote:"The patients, obstetrical staff, and nursing staff remained blinded to the epidural pump settings and group assignment throughout the study. The anesthesia providers were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Although patients, obstetrical staff, and nursing staff were blinded, the anaesthesia providers were not blinded and the article did not state who collected outcome data.
Incomplete outcome data (attrition bias) All outcomes	High risk	High attrition: AMB: 9 of 50 participants randomised excluded from analysis, 2 participants from BI group received AMB and were analysed under AMB BI: 13 of 50 participants randomised excluded from analysis.
Selective reporting (reporting bias)	Low risk	All a priori outcomes reported based on published protocol
Other bias	Low risk	Appears to be free of other bias. Sample size calculation: 50 participants in each group was needed to detect an effect size of 0.056 change in pain score with an alpha less than 0.05 and a power greater than 80%