Krishnamurthy 2015.

Methods	Randomly allocated using computer generated random number table. Allocation concealed using sequentially numbered opaque envelopes.Inpatient setting in India.
Participants	Inclusion criteria: primigravida, singleton, cephalic presentation, 38 weeks gestation or more, modified Bishop score of less than 6. Exclusion criteria: under 18 years old, uterine scar, ruptured membranes, uterine contractions, medical complications, contraindications to vaginal delivery or isosorbide mononitrite therapy.
Interventions	100 recruited, 100 randomised into 2 groups: 50 women received 40 mg isosorbide mononitrite inserted vaginally into posterior fornix, second dose given 12 hours later if Bishop score still less than 6, 50 received 40 mg placebo (pyridoxine) administered the same way as intervention.
Outcomes	Maternal: change in modified Bishop Score at 12 and 24 hours after drug insertion, time from initiation of cervical ripening till delivery, labour duration, need of oxytocin augmentation, mode of delivery, uterine hyperstimulation, tachysystole, headache, tachycardia, palpitations, hypotension, nausea and vomiting, proportions of unripe cervix (Bishop Score < 6) at 24 hr after first drug insertion. Neonatal: Apgar scores < 7 at 1 min and 5 min, fetal distress, NICU admissions, length of neonatal stay in NICU.
Notes	Absense of headache, nausea, vomiting and palpitations only mentioned referring to IMN group in text. No side effects mentioned for control group.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly allocated into 2 groups using a computer‐generated random number table.
Allocation concealment (selection bias)	Low risk	Opaque, sequentially numbered envelopes
Incomplete outcome data (attrition bias) All outcomes	Low risk	No evidence to the contrary.
Selective reporting (reporting bias)	Low risk	No evidence to the contrary.
Other bias	Unclear risk	No evidence to the contrary.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	'drug insertion was done by a senior resident who was not part of the investigation'. Dummy used as placebo therefore assuming patients blinded as well.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated.