Krammer 1995a.

Methods	RCT. Computer‐generated sequence. No details were given on the method for concealment of the allocation.
Participants	Term women with a BS < 9, absence of contraindication for labour and fetal distress. 441 women (224 in the Dilapan group and 217 in the PGE2 group).
Interventions	Dilapan, as many dilators as possible (224 randomised, 214 analysed); intracervical PGE2 0.5 mg (217 women randomised, 202 analysed). In both groups, ripening was followed 6 hours later by oxytocin.
Outcomes	CS, uterine hyperstimulation, fetal and neonatal infection.
Notes	25 women excluded: 10 in the Dilapan group (8 protocol violations, 2 entered spontaneous labour before insertion) and 15 in the PG group (10 protocol violations, 3 entered labour before ripening and 2 delivered before the 6‐hour interval). Authors stated that including these excluded women do not alter the results. Numbers of CS derived from Williams 1997. Setting: Tampa general hospital, USA Dates of study: June 1991 ‐ December 1993 Funding sources: not reported Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated sequence
Allocation concealment (selection bias)	Unclear risk	Not reported
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	Not reported
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT was performed, but 25 women excluded: 10 in the Dilapan group (8 protocol violations, 2 entered spontaneous labour before insertion) and 15 in the PG group (10 protocol violations, 3 entered labour before ripening and 2 delivered before the 6‐hour interval)
Selective reporting (reporting bias)	Low risk	All pre‐specified outcomes reported
Other bias	Low risk	No other bias detected