Sanchez‐Ramos 1992.

Methods	RCT. Computer‐generated allocation sequence. No details on concealment of allocation.
Participants	Singleton vertex term pregnancies, intact membranes, BS < 6. Excluded if non‐reassuring FHR, placenta praevia, previous uterine scar, cervicitis.
Interventions	Hygroscopic cervical dilators (as many as possible) (36 women); (PGE2) 4 mg gel applied to the cervical os (n = 38). After 8‐12 hours, repeat in both groups if cervix unfavourable. Followed by oxytocin and amniotomy.
Outcomes	CS, instrumental vaginal delivery, haemorrhage, admission to NICU, infection.
Notes	Unclear whether PG was intracervical or intravaginal. Setting: Univerity medical Center of Jacksonville, USA. largely high risk, low income obstetric population Study period: June 1988 to July 1989 Funding: 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 randomisation list
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	Unclear risk	ITT not reported and not clear if done, no missing data or cases reported
Selective reporting (reporting bias)	Unclear risk	No outcomes pre specified in method section
Other bias	Low risk	No other bias detected