1. Types of participants.
| Trial ID | Reason for hospitalisation | Type of surgery/reason for being admitted | Gender |
| Ahmed 2014 | Elective gynaecological surgery | Total abdominal hysterectomy with or without bilateral salpingo‐oophorectomy | Female |
| Alessandri 2006 | Elective gynaecological surgery | Vaginal hysterectomy | Female |
| Allen 2016 | Patients undergoing cardiothoracic surgery | General thoracic surgical procedure, in whom an epidural catheter was placed for analgesia | Mixed |
| Alonzo‐Sosa 1997 | Elective gynaecological surgery | Anterior colporrhapy, anterior and posterior colporrhaphy with or without vaginal hysterectomy | Female |
| Aref 2020 | Elective CS | Participants admitted for elective CS | Female |
| Aslam 2019 | Elective gynaecological surgery | Participants undergoing minimally invasive pelvic organ prolapse surgery | Female |
| Azarkish 2003 | Elective CS | Participants admitted for elective CS | Female |
| Azarkish 2005 | Emergency CS | Participants admitted for emergency CS | Female |
| Barone 2015 | Elective gynaecological surgery | Participants admitted for vaginal fistula repair | Female |
| Basbug 2020 | Elective CS | Participants admitted for elective CS | Female |
| Benoist 1999 | Elective GI surgery | Extensive rectal resection (total or subtotal proctectomy) | Mixed |
| Bristoll 1989 | Not reported | Not reported | Unknown |
| Carpiniello 1988 | Elective orthopaedic surgery | Total joint replacement (hip or knee) | Female |
| Carter‐Brooks 2018 | Elective gynaecological surgery | Participants undergoing pelvic organ prolapse surgery | Female |
| Chai 2011 | Elective gynaecological surgery | Total abdominal hysterectomy with or bilateral salpingo‐oophorectomy for various benign gynaecological diseases | Female |
| Chen 2013 | Admitted to ICU | Patients requiring mechanical ventilation for respiratory failure | Mixed |
| Chia 2009 | Elective cardiothoracic surgery | Thoracotomy | Mixed |
| Chillington 1992 | Elective urological surgery | TURP | Male |
| Cornia 2003 | Admitted to medicine and cardiology services | Patients admitted to the medicine and cardiology services | Mixed |
| Coyle 2015 | Elective GI surgery | Elective transabdominal colectomy, proctectomy or coloproctectomy | Mixed |
| Crowe 1993 | Admitted to urology ward | Patients admitted to the urology ward with IUCs or who were catheterised during their inpatient stay | Mixed |
| Dunn 1999 | Elective obstetric and gynaecological surgery | Patients undergoing elective obstetric or gynaecological surgery | Female |
| Dunn 2000b | Elective gynaecological surgery or CS | Patients undergoing hysterectomy or CS who do not require bladder suspension or strict fluid management | Female |
| Dunn 2003 | Elective gynaecological surgery | Women undergoing hysterectomy for various benign diseases (e.g. fibroid tumours, abnormal uterine bleeding, chronic pain, and persistent cervical dysplasia or micro invasive cancer | Female |
| Durrani 2014 | Elective urological surgery | Patients with bladder outflow obstruction due to benign prostatic enlargement undergoing TURP | Male |
| El‐Mazny 2014 | Primary or elective CS | Patients admitted to the prenatal wards for primary or repeat elective CS | Female |
| Ganta 2005 | Elective urological surgery | TURP | Male |
| Glavind 2007 | Elective gynaecological surgery | Patients undergoing any type of vaginal prolapse surgery | Female |
| Gong 2017 | Elective gynaecological surgery | Patients undergoing radical hysterectomy for cervical cancer FIGO stage IB‐IIB | Female |
| Gross 2007 | Admitted to stroke ward | Patients with a stroke admitted to the ward | Mixed |
| Gungor 2014 | Elective gynaecological surgery | Patients with pelvic organ prolapse and/or urinary incontinence undergoing anterior colporrhaphy | Female |
| Guzman 1994 | Elective gynaecological surgery | Patients undergoing vaginal surgery | Female |
| Hakvoort 2004 | Elective gynaecological surgery | Patients undergoing anterior colporrhaphy for vaginal prolapse surgery | Female |
| Hall 1998 | Elective general surgery | Patients admitted to the general surgery wards | Mixed |
| Han 1997 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Hewitt 2001 | Elective urological surgery | Patients requiring radical perineal prostatectomy | Male |
| Huang 2011 | Elective gynaecological surgery | Patients with cystocele of at least stage II, who were symptomatic and desired operative treatment with anterior vaginal repair with or without other concomitant pelvic surgeries | Female |
| Ind 1993 | Elective hysterectomy, posterior exenteration, colposuspension, anterior colporrhaphy, total/radical vulvectomy, radical oophorectomy, ovarian cystectomy, adhesiolysis myomectomy | Patients which were admitted for any of the following operations: hysterectomy, posterior exenteration, colposuspension, anterior colporrhaphy, total/radical vulvectomy, radical oophorectomy, ovarian cystectomy, adhesiolysis myomectomy | Female |
| Irani 1995 | Elective transurethral prostatic surgery | Patients admitted for transurethral prostatic surgery due to benign hyperplasia | Male |
| Iversen Hansen 1984 | Urethral strictures | Patients with urethral strictures | Not reported |
| Jang 2012 | Surgery for rectal cancer | Patients undergoing elective rectal surgery for cancer | Mixed |
| Jeong 2014 | Robot‐assisted laparoscopic radical prostatectomy | Patients with localised or advanced prostate cancer | Men |
| Joshi 2014 | Elective hysterectomy with salpingo‐oophorectomy | Patients undergoing uneventful hysterectomy with salpingo‐oophorectomy | Female |
| Jun 2011 | Elective TURP | Patients admitted for TURP | Male |
| Kamilya 2010 | Vaginal prolapse surgery | Patients undergoing vaginal prolapse surgery | Female |
| Kelleher 2002 | Urological surgery | Patients admitted to urology or renal unit | Not reported |
| Kim 2012 | Radical prostatectomy | Patients undergoing extraperitoneal laparoscopic radical prostatectomy | Men |
| Koh 1994 | Elective TURP | Patients admitted for TURP | Men |
| Kokabi 2009 | Anterior colporrhaphy for pelvic organ prolapse | Patients undergoing anterior colporrhaphy due to pelvic organ prolapse and stress incontinence | Female |
| Lang 2020 | Elective gynaecological surgery | Patients admitted for elective benign gynaecological surgery | Female |
| Lau 2004 | Elective general surgery | Patients admitted for elective general surgery | Mixed |
| Li 2014 | Elective TURP | Patients admitted for TURP | Men |
| Liang 2009 | Laparoscopic vaginal hysterectomy | Patients admitted for laparoscopic vaginal hysterectomy | Female |
| Lista 2020 | Elective urological surgery | Patients admitted for robot‐assisted radical prostatectomy for localised prostate cancer | Male |
| Liu 2015 | Neurosurgery | Patients undergoing neurosurgery | Mixed |
| Lyth 1997 | TURP or bladder neck incision | Patients undergoing TURP or bladder neck incision | Unclear |
| Mao 1994 | Elective gynaecological surgery | Patients undergoing surgery for total hysterectomy or salpingo‐oophorectomy | Female |
| Matsushima 2015 | Surgery for prostate cancer removal (unclear what operation was done) | Patients with prostate cancer | Male |
| McDonald 1999 | TURP | Patients undergoing TURP | Male |
| Naguimbing‐Cuaresma 2007 | Elective CS | Participants admitted for elective CS | Female |
| Nathan 2001 | Elective gynaecological surgery | Patients undergoing surgery for benign gynaecological conditions | Female |
| Nguyen 2012 | Elective urological surgery for urethral strictures | Patients undergoing surgery for urethral strictures | Unclear |
| Nielson 1985 | Elective urological surgery for urethral strictures | Patients undergoing surgery for urethral strictures | Unclear |
| Noble 1990 | Elective urological surgery and procedures | Patients admitted to the urological unit | Mixed |
| Nyman 2010 | Orthopaedic surgery | Patients admitted with hip fractures in need of surgery | Mixed |
| Oberst 1981 | Elective general surgery | Patients undergoing surgery for bowel cancer; low anterior bowel resection or abdominoperineal resection | Mixed |
| Onile 2008 | Elective CS | Patients admitted for elective CS | Female |
| Ouladsahebmadarek 2012 | Elective gynaecological surgery | Patienst admitted for elective abdominal hysterectomy or laparotomy for being pathology (fibroma, AUB, chronic pelvic pain, ovarian cysts etc.) | Female |
| Pervaiz 2019 | Elective urological surgery | Patients undergoing TURP | Male |
| Popiel 2017 | Elective gynaecological surgery | Patients undergoing robotic sacrocolpopexy for vaginal prolapse | Female |
| Rajan 2017 | Elective gynaecological surgery | Patients undergoing surgery for Ward Mayo operation; Manchester repair; vaginal hysterectomy and amputation of cervix | Female |
| Ruminjo 2015 | Elective gynaecological surgery | Patients undergoing fistula repair surgery | Female |
| Sahin 2011 | Elective urological surgery | Patients admitted for TURP due to benign prostate hypertrophy | Male |
| Sandberg 2019 | Elective gynaecological surgery | Patients undergoing laparoscopic hysterectomy | Female |
| Schiotz 1995 | Elective gynaecological surgery | Patients admitted for vaginal plastic surgery (anterior colporrhaphy, anterior plus posterior colporrhaphy or a full Manchester repair) | Female |
| Schiotz 1996 | Elective urogynaecological surgery | Patients admitted for elective retro‐pubic surgery for stress incontinence | Female |
| Sekhavat 2008 | Elective gynaecological surgery | Patients undergoing anterior colporrhaphy | Female |
| Shahnaz 2016 | Elective gynaecological surgery | Patients undergoing surgery for pelvic organ prolapse | Female |
| Shrestha 2013 | Elective gynaecological surgery | Patients admitted for vaginal hysterectomy, anterior colporrhaphy or Manchester operations | Female |
| Souto 2004 | Elective urological surgery | Patients admitted for retropubic radical prostatectomy | Male |
| Sun 2004 | Elective urogynaecological surgery | Patients admitted for Burch's colposuspension | Female |
| Tahmin 2011 | Elective gynaecological surgery | Patients with genital prolapses admitted for vaginal hysterectomy and or pelvic floor repair | Female |
| Talreja 2016 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Taube 1989 | AUR | Patients admitted to the hospital with AUR | Male |
| Toscano 2001 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Valero Puerta 1998 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Vallabh‐Patel 2020 | Elective gynaecological surgery | Patients undergoing robotic sacrocolpopexy for pelvic organ prolapse | Female |
| Webster 2006 | General surgery and medical patients | Patients who required IUC on general surgery and medical wards | Mixed |
| Weemhoff 2011 | Elective gynaecological surgery | Patients admitted for anterior colporrhaphy | Female |
| Williamson 1982 | Elective surgery (unspecific) | Patients undergoing surgery (not specified by trial) | Female |
| Wilson 2000 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Wu 2015 | Elective gallbladder or biliary tree surgery | Pateints undergoing gallbladder or biliary tree surgery | Mixed |
| Wyman 1987 | Elective urological surgery | Patients with benign prostatic enlargement undergoing TURP | Male |
| Yaghmaei 2017 | Elective CS | Patients who underwent CS | Female |
| Yee 2015 | Elective CS | Patients who underwent CS under spinal anaesthesia | Female |
| Zaouter 2009 | Elective major abdominal and thoracic surgery | Patients admitted for elective major abdominal and thoracic surgery | Mixed |
| Zhou 2012 | Elective CS | Patients who underwent CS | Female |
| Zmora 2010 | Elective colon and rectal surgery with pelvic dissection | Patients admitted for elective colon and rectal surgery | Mixed |
| Zomorrodi 2018 | Elective renal transplant surgery | Patients with end‐stage renal failure undergoing renal transplant surgery | Mixed |
AUB: abnormal uterine bleeding; AUR: acute urinary retention; CS: cesarean section; GI: gastrointestinal; FIGO: International Federation of Gynecology and Obstetrics; ICU: intensive care unit; IUC: indwelling urethral catheter; TURP: transurethral resection of the prostate