Table 1.
Baseline demographics and obstetric characteristics of intention to treat population (n=2035)
| Demographic and obstetric characteristics | No (%) participants* | Risk difference (95% CI) | |
|---|---|---|---|
| Closed incision NPWT (n=1017) | Standard dressing (n=1018) | ||
| Mean (SD) age†, years | 31 (5.5) | 31 (5.4) | 0 (–0.47 to 0.47) |
| Pre-pregnancy body mass index‡: | |||
| 30.0-34.9 | 488 (48.0) | 524 (51.5) | –3.49 (–9.61 to 2.64) |
| 35.0-39.9 | 268 (26.4) | 247 (24.3) | 2.09 (–2.28 to 6.46) |
| 40.0-49.9 | 218 (21.4) | 211 (20.7) | 0.71 (–3.28 to 4.70) |
| Smoker | 101 (9.9) | 117 (11.5) | –1.56 (–4.41 to 1.28) |
| Comorbidities: | |||
| Gestational diabetes | 292 (28.7) | 288 (28.3) | 0.42 (–4.21 to 5.06) |
| Diabetes mellitus | 38 (3.7) | 39 (3.8) | –0.09 (–1.78 to 1.60) |
| Hypertension | 140 (13.8) | 129 (12.7) | 1.09 (–2.07 to 4.25) |
| Respiratory disease | 124 (12.2) | 142 (13.9) | –1.76 (–4.90 to 1.39) |
| Anaemia (Hb<110 g/L) in third trimester | 99 (9.7) | 83 (8.2) | 1.58 (–1.02 to 4.18) |
| Diagnosed and treated depression | 97 (9.5) | 103 (10.1) | –0.58 (–3.30 to 2.14) |
| Thromboembolic disease | 82 (8.1) | 83 (8.2) | –0.09 (–2.56 to 2.38) |
| Hypercholesterolaemia pre-pregnancy† | 10 (1.0) | 4 (0.4) | 0.59 (–0.13 to 1.31) |
| Immunocompromise (on immunosuppressive therapy) | 4 (0.4) | 5 (0.5) | –0.09 (–0.68 to 0.48) |
| Parity: | |||
| 0 | 233 (22.9) | 264 (25.9) | –3.02 (–7.32 to 1.27) |
| 1 | 358 (35.2) | 374 (36.7) | –1.54 (–6.75 to 3.67) |
| 2 | 247 (24.3) | 202 (19.8) | 4.44 (0.36 to 8.53) |
| ≥3 | 179 (17.6) | 178 (17.5) | 0.12 (–3.52 to 3.76) |
| No of previous caesarean sections: | |||
| None | 381 (37.5) | 421 (41.4) | –3.89 (–9.35 to 1.56) |
| 1 | 379 (37.3) | 383 (37.6) | –0.35 (–5.67 to 4.96) |
| 2 | 186 (18.3) | 156 (15.3) | 2.97 (–0.60 to 6.53) |
| 3 | 57 (5.6) | 44 (4.3) | 1.28 (–0.65 to 3.22) |
| ≥4 | 14 (1.4) | 14 (1.4) | 0 (–1.02 to 1.02) |
| Status of membrane†: | |||
| Intact | 874 (85.9) | 855 (84.0) | 1.95 (–6.06 to 9.96) |
| Ruptured (≤12 h) | 77 (7.6) | 80 (7.9) | –0.29 (–2.70 to 2.13) |
| Ruptured (>12 h) | 65 (6.4) | 83 (8.2) | –1.76 (–4.11 to 0.58) |
| Surgery types: | |||
| Elective caesarean section | 740 (72.8) | 732 (71.9) | 0.86 (–6.53 to 8.25) |
| Semi-urgent caesarean section | 277 (27.2) | 286 (28.1) | –0.86 (–5.43 to 3.71) |
| ASA status: | |||
| 1 | 65 (6.4) | 76 (7.5) | –1.07 (–3.36 to 1.21) |
| 2 | 664 (65.3) | 641 (63.0) | 2.32 (–4.64 to 9.28) |
| 3 | 283 (27.8) | 294 (28.9) | –1.05 (–5.68 to 3.57) |
| ≥4 | 5 (0.5) | 7 (0.7) | –0.20 (0.86 to 0.47) |
| Median (IQR) length of surgery, min† | 63 (51.0-77.0) | 60 (49.0-75.0) | 1.37 (–0.95 to 3.69) |
| Hair removal methods†: | |||
| None | 138 (13.6) | 120 (11.8) | 1.78 (–1.31 to 4.88) |
| Shaved | 164 (16.1) | 159 (15.6) | 0.51 (–2.95 to 3.97) |
| Waxed | 56 (5.5) | 54 (5.3) | 0.20 (–1.81 to 2.22) |
| Depilatory cream | 5 (0.5) | 2 (0.2) | 0.30 (–0.21 to 0.80) |
| Clipped | 653 (64.2) | 682 (67.0) | –2.79 (–9.82 to 4.25) |
| Skin preparation†: | |||
| Aqueous chlorhexidine | 74 (7.3) | 71 (7.0) | 0.30 (–2.02 to 2.62) |
| Aqueous betadine | 451 (44.3) | 462 (45.4) | –1.04 (–6.86 to 4.78) |
| Alcoholic chlorhexidine | 468 (46.0) | 459 (45.1) | 0.936 (–4.94 to 6.79) |
| Alcoholic betadine | 22 (2.2) | 25 (2.5) | –0.29 (–1.61 to 1.03) |
| Prophylactic antibiotics: | |||
| Not given | 8 (0.8) | 12 (1.2) | –0.39 (–1.25 to 0.47) |
| Pre-incision | 985 (96.9) | 975 (95.8) | 1.08 (–7.45 to 9.61) |
| Post-incision | 24 (2.4) | 31 (3.0) | –0.69 (–2.11 to 0.74) |
| Wound closure: | |||
| Subcutaneous (fat) closure | 966 (95.0) | 976 (95.9) | –0.89 (–9.38 to 7.60) |
| Subcuticular (skin) suture | 998 (98.1) | 992 (97.4) | 0.69 (–7.91 to 9.28) |
| Interrupted suture | 7 (0.7) | 9 (0.9) | 0.20 (–0.97 to 0.57) |
| Staples (skin) | 10 (1.0) | 17 (1.7) | 0.69 (–1.69 to 0.31) |
| Wound glue | 2 (0.2) | 0 (0) | –0.20 (–0.08 to 0.47) |
ASA=American Society of Anesthesiologists; Hb=haemoglobin; IQR=interquartile range; NPWT=negative pressure wound therapy.
*
Percentages might not add up because of rounding.
†
Missing data for ≤5 women.
‡
Weight in kilograms divided by square of height in meters.