Garshasbi 2010.

Methods	Prospective RCT conducted in 1 hospital, Shahid Mostafa Khomeini, Tehran, Iran.
Participants	500 women, CS (no information on parity, previous CS or if CS was elective or not); no information on type of anaesthesia.
Interventions	Intervention group (N = 238): "Patients in the gum‐chewing group chewed gum" (no info on type) 3 x/d at least 30 min each time immediately after surgery until regular diet was initiated. Total 90 min/d. Control group (N = 262): no information available about diet protocol in control group.
Outcomes	Time to first postoperative passage of flatus (in median), time to first bowel movement (in median), length of hospital stay (no numerical data), time to first hearing bowel sounds (no standard deviation), tolerance to gum and rate of ileus.
Notes	This study was published only as a congress abstract. We wrote to the study author for additional information but got no response. Due to the form the data were presented (median, no standard deviation, no numerical data), we could not use the time to passage of flatus or stools, nor duration of hospital stay, nor time to first bowel sounds in our meta‐analyses. We only used rate of ileus and tolerance to gum. No study protocol available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information: "500 pregnant women who underwent a CS were randomly divided into two groups...".
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 participants. No information provided about blinding personnel.
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 and tolerance to gum.
Blinding of outcome assessment (detection bias) Objective outcomes	Unclear risk	No information on blinding of outcome assessors for hearing of bowel sounds, ileus and length of hospital stay.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses reported.
Selective reporting (reporting bias)	Unclear risk	None of the outcomes reported in the results were pre‐specified in the methods section. This study was published only as a congress abstract and no protocol was available.
Other bias	Unclear risk	No information available.