Guinn 2000.

Methods	RCT. Computer‐generated sequence. Opaque, sealed, sequentially numbered envelopes.
Participants	Singleton, vertex presentation, intact membranes. Unfavourable cervix (< 2 cm dilated and effacement < 75%). Exclusion: bleeding, labour, asthma. prior vertical uterine incision, acute fetal compromise
Interventions	Laminaria and IV oxytocin: as many laminaria as possible were kept for 12 hours, unless expelled or membranes ruptured. IV oxytocin was simultaneously given (165 women); EASI + IV oxytocin: Foley catheter balloon filled with 30 mL of water followed by saline infusion 30 mL/hour. IV oxytocin was simultaneously given (169 women); PGE2 intracervical gel 0.5 mg/6H, max 2 doses. IV oxytocin was started if not in labour after 2 doses of PGE2 (110 women).
Outcomes	CS, delay to delivery, delivery within 24 hours, infections, haemorrhage.
Notes	After interim analysis, the authors stopped recruiting in the PGE2 group. 68 protocol violations, but ITT analysis was conducted. Setting: University of Alabama and Cooper Green Hospitals Birmingham, Alabama Dates of study: January 1994 to August 1997 Funding sources: UpJohn Pharmaceuticals provided funds to purchase study drugs Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random number table
Allocation concealment (selection bias)	Low risk	Opaque sealed envelopes
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	Low risk	ITT
Selective reporting (reporting bias)	Unclear risk	All pre‐specified outcomes reported for laminaria and EASI
Other bias	Unclear risk	After interim analysis, the authors stopped recruiting in the PGE2 group.