Predominant category during the first hour of admission, N (%)a | Cases (N = 24)b | Controls (N = 100)c | P-valuef |
 |  |  | 0.20 |
 Category 1 | 14 (58.3%) | 71 (71.0%) |  |
 Category 1 or 2 | 2 (8.3%) | 6 (5.8%) |  |
 Category 2 | 7 (29.2%) | 2 (23.1%) |  |
 Category 2 or 3 | 1 (4.2%) | 0 |  |
 Category 3 | 0 | 0 |  |
Predominant category during the last hour prior to delivery, N (%)a | Cases (N = 25)d | Controls (N = 101)e | P-valuef |
 |  |  | 0.02 |
 Category 1 | 1 (4.0%) | 8 (7.9%) |  |
 Category 1 or 2 | 1 (4.0%) | 11 (10.9%) |  |
 Category 2 | 20 (80.0%) | 82 (81.2%) |  |
 Category 2 or 3 | 2 (8.0%) | 0 |  |
 Category 3 | 1 (4.0%) | 0 |  |