Pourmaleky 2013.

Study characteristics
Methods	Single‐blind randomised trial
Participants	Multiparous women who had normal vaginal delivery in Mahshahr Hospital, Iran. The pregnant women were randomly divided into 2 groups of 61 cases in zintoma and 61 cases in mefenamic acid groups. Using the VAS, after‐pain was determined during the first 2 hours after delivery and participants received zintoma and mefenamic acid if the pain score ≥ 4 was expressed by participants
Interventions	Intervention group 1: Ginger, capsule 250 mg oral‐ for 6 hours for 24 hours, brand name: Zintoma, manufacturer: Goldaru (N = 61) women (source: English abstract) Intervention 2, Mefenamic acid, oral capsule, 250 mg, for 6 hours for 24 hours, brand name: Ponstan, manufacturer: Razak (N = 61) women (source: English abstract)
Outcomes	The intensity of after‐pain, before intervention and 30 minutes after intervention, for each of the 4 doses. English abstract reports no side effects experienced by any of the women
Notes	Translation received 26 July 2020 Funding University of Medical Sciences, Ahvaz, Iran
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Only states study is randomised
Allocation concealment (selection bias)	Unclear risk	Allocation states use of ‘pocket’.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information provided about blinding of participants. Abstract describes this as "single blind", and translation indicates that researchers were blinded: 'In order for researcher not to be aware of the prescribed drug, the drugs were coded and given by 1 of the midwife’s colleagues'. It is unclear if women were blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	English abstract states 61 women randomised to each group, translation states 120 in total. Data have been reported on 115 women. Only 4% ‐ 6% of randomised women lost to follow‐up. Unclear how many women included in reporting of outcomes
Selective reporting (reporting bias)	Unclear risk	Data have not been included in the translation
Other bias	Unclear risk	Abstract only in English, full text required translation