Aref 2020.

Study characteristics
Methods	Study design: RCT Dates study conducted: September 2016–April 2018
Participants	Population: women Setting: Taif, Saudi Arabia Inclusion criteria: pregnant women with term singleton pregnancy prepared for term elective CS either primary or repeated Condition for hospitalisation: elective CS Exclusion criteria: women who had UTIs pre‐operatively, confirmed by urine analysis ± culture and sensitivity, women with iatrogenic bladder injury so that IUC had to be kept post‐operatively on the surgeon’s decision, women with severe pre‐eclampsia or eclampsia and/or any other conditions requiring post‐operative monitoring of urinary output, and women who had spinal anaesthesia by choice or contraindicated for general anaesthesia Number of participants: 238 eligible; 221 randomised; 221 reported Age (mean and SD): A 26.1 ± 4, B 25.3 ± 2, C 25.6 ± 3 Use of antibiotic prophylaxis: all participants received a single dose of prophylactic antibiotic in the form of ceftriaxone 1 g IM
Interventions	Group A (n = 73): IUC removal immediately after surgery Group B (n= 81): IUC removal 6 h post‐op Group C (n = 67): IUC removal 24 h after operation Size and type of catheter used: size 12 silicone, 2‐way Foley’s catheter Study definition of short‐term catheterisation (days): up to 24 h Intended duration of catheterisation for each group: Group A: immediate removal after surgery (n = 73) Group B: removal 6 h post‐op (n = 81) Group C: removal 24 h post‐op (n = 67)
Outcomes	Number of participants requiring recatheterisation Symptomatic UTI (number of participants) Time to first ambulation (h; mean ± SD) Length of hospital stay (days; mean ± SD) Positive urine culture Fever Dysuria
Definition of CAUTI or bacteriuria	“The diagnosis of symptomatic UTI was based on the following criteria: significant bacteriuria with at least one of the following symptoms; dysuria, frequency of micturition, urgency, supra pubic pain, or burning sensation at micturition.”
Sponsorship/funding	Not reported
Ethical approval	“This study was carried out in accordance with the ethical principles for medical research involving human subjects included in Helsinki declaration and was approved by Ethical Committee.”
Notes	“Urinary retention defined as: inability for spontaneous micturition within 6 h after the removal of urinary catheter” “Seventeen patients were finally excluded from the study; five patients had intraoperative complications (iatrogenic bladder injury) and therefore an indwelling catheter had to be kept postoperatively on the surgeon’s request while 12 did not complete the postoperative follow‐up.”
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “were divided into three groups by simple randomization using computer‐generated random numbers.” Comment: adequate randomisation method
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not reported. Unlikely given nature of intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported. Unlikely outcomes are affected by non‐blinding however.
Blinding of microbiological outcome (detection bias)	Low risk	Not reported. Assume microbiologist was blinded to participants of the study
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data
Selective reporting (reporting bias)	Low risk	Appears to be free form reporting bias
Other bias	Low risk	Appears to be free from other sources of bias