Roberts 1986.

Methods	RCT
Participants	Unfavourable cervix (BS < 5). Women with previous history of uterine surgery, fetal malpresentation or multiple gestation were excluded.
Interventions	4 groups: PGE1 in Tylose gel 3 mg (27 women) (exclude); laminaria tents (28 women); oxytocin 1 mU/minute (25 women); no treatment (24 women exclude). Then oxytocin was given in all groups.
Outcomes	CS.
Notes	Successful IOL and fetal distress not defined. Setting: Jackson, USA Dates of study: not reported Funding: supported by the Vicksburg hospital medical foundation: Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly ordered envelopes, not clear how
Allocation concealment (selection bias)	Low risk	Drawing a sealed envelope by a third party
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not feasible due to nature of intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT not reported, although this is likely as numbers are equal to randomised numbers. no missing cases or data
Selective reporting (reporting bias)	Unclear risk	No outcomes pre specified in method section
Other bias	Low risk	No other bias detected