Shang 2010.

Methods	Prospective RCT, Linyi Women and Children's Hospital, Shandong Province, China.
Participants	388 randomised, but only 386 women undergoing CS under spinal anaesthesia were reported. 2 women had incomplete data and were excluded. Median parity 2, ranging from 1‐4, no information on proportion of women with a previous CS; included both elective or non‐elective CS. Mean age: 29.4 ± 5.4 and 29.9 ± 6.4 years (intervention group and control groups). Inclusion criteria: women 19‐44 years undergoing CS. Exclusion criteria: women with "pre‐existing gastrointestinal disorders, such as peptic ulcer, hiatus hernia, irritable bowel syndrome, or esophagitis, and those with an intraoperative blood loss exceeding 500 mL".
Interventions	Intervention group (N = 195): chewed sugar‐free peppermint‐flavoured gum "for least half an hour" 3 times/d (total time chewing = at least 90 min/d) as soon as returning from the operating theatre, until the time they defecated or were discharged. No information on compliance to gum‐chewing. Control group (N = 191): nil‐by‐mouth until passage of flatus (conventional protocol).
Outcomes	Time to first passage of flatus, to first bowel sounds, defecation, rate of mild ileus (mild anorexia, abdominal cramps, non‐persistent nausea or vomiting), rate of severe ileus (abdominal distention, > 4 episodes vomiting/24 hours, intolerance to oral fluids, need for abdominal X‐rays or nasograstric decompression), duration of hospital stay, use of antiemetics/analgesics, tolerance of gum chewing. Additional outcome: time to lactation.
Notes	No study protocol available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Patients were randomly assigned to one of two groups by consecutive opening of sequentially numbered, opaque, sealed envelopes. Envelope randomisation was performed by a computer‐generated code using the blocked randomisation method."
Allocation concealment (selection bias)	Low risk	"Patients were randomly assigned to one of two groups by consecutive opening of sequentially numbered, opaque, sealed envelopes."
Blinding of participants and personnel (performance bias) All outcomes	High risk	The obstetricians involved in the intraoperative care of the participants were blinded to the assigned group. The nature of intervention did not allow blinding of participants.
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Participants were unable to be adequately blinded in relation to passage of flatus or stools or satisfaction.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	For time to first bowel sounds, ileus, use of additional analgesics/antiemetics and duration of hospital stay. "The patients' postoperative progress was assessed by an independent investigator (investigator B) who was blinded to the assigned treatment. Participants were taught not to reveal to the surgeon, surgical team, nurse or investigators to which arm they had been randomised."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Drop out rate: 0.5% (2/388 randomised).
Selective reporting (reporting bias)	Low risk	All pre‐specified outcomes proposed in Methods were reported in Results. No protocol available for this study.
Other bias	Unclear risk	No information available.