Akhlaghi 2008.

Methods	RCT in 1 hospital, Mashhad Zeinab, Iran.
Participants	400 women, elective CS. No information on anaesthesia or parity or previous CS. Mean age: 27.3 years in intervention group and 26.6 years in control group. Exclusion criteria: complications during or after surgery.
Interventions	Intervention group (N = 200): chewed sugar‐free and flavourless gum after regaining consciousness after surgery, for 45 min per session, 3 times/d at 8:00, 14:00 and 20:00 (total 135 min/d), until the regular diet was initiated. Control group (N = 200): routine care which consisted of "restriction of oral intake until the bowel function was returned" (conventional feeding).
Outcomes	Time of the first flatus passage, bowel sound*, defecation, duration of hospital stay and gum tolerability. Additional outcomes: time to ambulation post CS and to initiation regular diet.
Notes	*Time to bowel sounds not included in meta‐analysis because there was only mean value and no information on standard deviation. We wrote to authors but obtained no response. No study protocol available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information available.
Allocation concealment (selection bias)	Unclear risk	No information available.
Blinding of participants and personnel (performance bias) All outcomes	High risk	"The nature of the study did not allow blinding after application of the assigned intervention."
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Participants were unable to be adequately blinded in relation to passage of flatus and stools or tolerability to gum.
Blinding of outcome assessment (detection bias) Objective outcomes	Unclear risk	No information on blinding of outcome assessors for hearing of bowel sounds and length of hospital stay, ileus or use of antiemetics or analgesics NA.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses.
Selective reporting (reporting bias)	Low risk	All pre‐specified outcomes in Methods were reported in Results.
Other bias	Unclear risk	No information.