Table 1

Cox regression results for risks of undergoing pelvic floor surgery (POP, UI and/or RP-FI)

Risk factorAll women (N=34 631)No operation (N=32 501)Operation (N=2130)UnadjustedAdjusted
N (%)N (%)N (%)HR (95% CI)p ValueHR (95% CI)p Value
Mode of delivery
 SVD/breech only21 210 (61.2%)19 776 (60.8%)1434 (67.3%)1.00
 CS only2551 (7.4%)2524 (7.8%)27 (1.3%)0.25 (0.16 to 0.36)<0.0010.27 (0.18 to 0.39)<0.001
 Instrumental (at least one forceps)9022 (26.1%)8433 (25.9%)589 (27.7%)1.14 (1.03 to 1.26)0.0071.13 (1.02 to 1.25)0.015
 Instrumental (at least one, but no forceps)663 (1.9%)639 (2.0%)24 (1.1%)1.42 (0.95 to 2.13)0.091.35 (0.90 to 2.02)0.15
 SVD+CS1185 (3.4%)1129 (3.5%)56 (2.6%)0.92 (0.70 to 1.20)0.530.89 (0.68 to 1.17)0.40
Age at first delivery
 Under 20 years5867 (16.9%)5510 (17.0%)357 (16.8%)0.88 (0.78 to 0.99)0.0350.87 (0.78 to 0.98)0.021
 20–29 years23 751 (68.6%)22 221 (68.4%)1530 (71.8%)1.001.00
 30–49 years5013 (14.5%)4770 (14.7%)243 (11.4%)1.11 (0.97 to 1.28)0.121.34 (1.16 to 1.54)<0.001
Total number of deliveries
 Single8699 (25.1%)8306 (25.6%)393 (18.5%)1.001.00
 2–424 986 (72.1%)23 323 (71.8%)1663 (78.1%)1.41 (1.26 to 1.58)<0.0011.30 (1.16 to 1.46)<0.001
 5+946 (2.7%)872 (2.7%)74 (3.5%)1.15 (0.90 to 1.48)0.271.10 (0.85 to 1.41)0.48
Twins at some point
 No34 148 (98.6%)32 044 (98.6%)2104 (98.8%)1.00
 Yes483 (1.4%)457 (1.4%)26 (1.2%)0.80 (0.54 to 1.17)0.25
Time between deliveries
 One delivery8699 (25.1%)8306 (25.6%)393 (18.5%)1.00
 All <2 years4151 (12.0%)3883 (11.9%)268 (12.6%)1.40 (1.19 to 1.63)<0.001
 All ≥2 years16 510 (47.7%)15 463 (47.6%)1047 (49.2%)1.40 (1.24 to 1.57)<0.001
 Mixture5271 (15.2%)4849 (14.9%)422 (19.8%)1.41 (1.23 to 1.62)<0.001
Type of perineal wound
 No wound14 365 (41.5%)13 601 (41.8%)764 (35.9%)1.001.00
 All episiotomy9457 (27.3%)8852 (27.2%)605 (28.4%)1.19 (1.07 to 1.33)0.0011.05 (0.94 to 1.18)0.37
 At least one third-degree tear162 (0.5%)150 (0.5%)12 (0.6%)1.99 (1.12 to 3.53)0.0181.68 (0.95 to 2.97)0.076
 No perineal tears (lacerations only)10 647 (30.7%)9898 (30.5%)749 (35.2%)1.57 (1.41 to 1.73)<0.0011.36 (1.22 to 1.52)<0.001
  • CS, caesarean section; POP, pelvic organ prolapse; RP-FI, rectal prolapse or faecal incontinence; SVD, spontaneous vaginal delivery; UI, urinary incontinence.