Table 5.
Relative and absolute risk of preterm birth by time from last excisional treatment to conception
| Time from last excisional treatment to conception (years) | No (%) cases | No (%) controls | Relative risk* (95% CI) | Absolute risk (%) |
|---|---|---|---|---|
| Women with large or very large excision (depth or volume) | ||||
| 0 to 0.5 | 13 (7) | 10 (8) | 0.88 (0.35 to 2.24) | 13.5 (1.7 to 25.3) |
| 0.5 to 1 | 12 (6) | 13 (11) | 0.62 (0.26 to 1.47) | 9.4 (1.9 to 17.0) |
| 1 to 3 | 52 (26) | 27 (22) | 1.04 (0.58 to 1.84) | 15.8 (8.6 to 23.1) |
| ≥3 | 123 (62) | 72 (59) | 1 (reference) | 15.3 (11.0 to 19.5) |
| Women with small, medium, or unknown excision (depth or volume) | ||||
| 0 to 0.5 | 27 (8) | 25 (6) | 1.37 (0.74 to 2.53) | 10.2 (4.3 to 16.2) |
| 0.5 to 1 | 28 (8) | 38 (9) | 0.84 (0.50 to 1.43) | 6.3 (3.2 to 9.5) |
| 1 to 3 | 100 (28) | 108 (25) | 1.17 (0.84 to 1.63) | 8.8 (6.4 to 11.1) |
| ≥3 | 196 (56) | 258 (60) | 1 (reference) | 7.5 (6.2 to 8.9) |
*Adjusted for parity, index of multiple deprivation, maternal age at delivery, and study site.