Haghighi 2015.

Methods	Non‐blinded parallel randomised controlled trial conducted on the midwifery ward of Shahid Akbar Abadi Hospital, Tehran, Iran. Used block randomisation.
Participants	149 nulliparous women were recruited to this study Inclusion criteria: nulliparous women, singleton, cephalic presentation, gestation over 40 weeks and 4 days, Bishop score less than 5, no contraindications for ISDN, no previous caesarean section, no uterine scar, no underlying disease, not required to have reactive nonstress test or normal biophysical profile ultrasound.
Interventions	149 nulliparous women were randomised into 3 groups: 50 received 40 mg ISDN, maximum 2 doses inserted vaginally after 4 hours, 49 received 20 mg ISDN orally, maximum 2 doses 4 hourly, 50 were the control and received no medication.
Outcomes	Suggested to be Bishop score change but prespecified outcomes are not explicit.
Notes	Monitiored for 4 hours following administration of medication then discharged home for 24 hours. We combined the oral and vaginal ISDN groups to create a single pair‐wise comparison with the control.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'selected by simple random sampling method'
Allocation concealment (selection bias)	Unclear risk	No details given.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Total numbers of groups are not given in the results tables.
Selective reporting (reporting bias)	High risk	Outcomes not prespecified.
Other bias	Unclear risk	None noted.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding.
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding.