Table 1.
Key characteristics of exposed and control pregnancies included in infection and vaccination analysesa
| Infected | Uninfected controls | Vaccinated | Unvaccinated controls | |
|---|---|---|---|---|
| Number of pregnancies | 4074 | 12222 | 11379 | 22758 |
| Median maternal age (min–max) | 29 (14–45) | 29 (14–46) | 32 (14–52) | 31 (15–53) |
| Maternal deprivation | ||||
| 1 (most deprived) | 1225 (30.1%) | 3089 (25.3%) | 1620 (14.2%) | 4890 (21.5%) |
| 2 | 1028 (25.2%) | 2556 (20.9%) | 1838 (16.2%) | 4449 (19.5%) |
| 3 | 681 (16.7%) | 2295 (18.8%) | 2138 (18.8%) | 4196 (18.4%) |
| 4 | 675 (16.6%) | 2404 (19.7%) | 2864 (25.2%) | 5100 (22.4%) |
| 5 (least deprived) | 465 (11.4%) | 1865 (15.3%) | 2917 (25.6%) | 4104 (18%) |
| Unknown/Missing | 0 (0%) | 13 (0.1%) | 2 (<0.1%) | 19 (0.1%) |
| Maternal ethnicity | ||||
| White | 3611 (88.6%) | 10108 (82.7%) | 9845 (86.5%) | 18851 (82.8%) |
| South Asian | 183 (4.5%) | 383 (3.1%) | 433 (3.8%) | 825 (3.6%) |
| Black/Caribbean/African | 57 (1.4%) | 205 (1.7%) | 132 (1.2%) | 479 (2.1%) |
| Other/mixed ethnicity | 156 (3.8%) | 437 (3.6%) | 468 (4.1%) | 909 (4.0%) |
| Unknown/Missing | 67 (1.6%) | 1089 (8.9%) | 501 (4.4%) | 1694 (7.4%) |
| Maternal urban/rural status | ||||
| Large urban areas | 1616 (39.7%) | 4136 (33.8%) | 4369 (38.4%) | 8219 (36.1%) |
| Other urban areas | 1644 (40.4%) | 4664 (38.2%) | 3548 (31.2%) | 8167 (35.9%) |
| Accessible small towns | 248 (6.1%) | 980 (8.0%) | 961 (8.4%) | 1842 (8.1%) |
| Remote small towns | 89 (2.2%) | 402 (3.3%) | 346 (3.0%) | 656 (2.9%) |
| Accessible rural areas | 373 (9.2%) | 1375 (11.3%) | 1459 (12.8%) | 2632 (11.6%) |
| Remote rural areas | 81 (2.0%) | 582 (4.8%) | 601 (5.3%) | 1073 (4.7%) |
| Unknown/Missing | 23 (0.6%) | 83 (0.7%) | 95 (0.8%) | 169 (0.7%) |
| Parity | ||||
| 0 | 1655 (40.6%) | 5430 (44.4%) | 4824 (42.4%) | 8528 (37.5%) |
| 1+ | 2298 (56.4%) | 6435 (52.7%) | 6164 (54.2%) | 13512 (59.4%) |
| Unknown/missing | 121 (3.0%) | 357 (2.9%) | 391 (3.4%) | 718 (3.2%) |
| Maternal clinical vulnerability | ||||
| Not clinically vulnerable | 3012 (73.9%) | 8698 (73.4%) | 8411 (73.9%) | 16680 (73.3%) |
| Clinically vulnerable | 1035 (25.4%) | 3141 (25.7%) | 2839 (24.9%) | 5879 (25.8%) |
| Extremely vulnerable | 27 (0.7%) | 113 (0.9%) | 129 (1.1%) | 199 (0.9%) |
| Maternal diabetes | ||||
| No diabetes | 3749 (92.0%) | 11430 (93.5%) | 10411 (91.5%) | 20864 (91.7%) |
| Pre-existing diabetes | 28 (0.7%) | 108 (0.9%) | 147 (1.3%) | 182 (0.8%) |
| Gestational diabetes | 297 (7.3%) | 684 (5.6%) | 821 (7.2%) | 1712 (7.5%) |
| Maternal smoking status | ||||
| Non-smoker | 2785 (68.4%) | 7976 (65.3%) | 8612 (75.7%) | 15548 (68.3%) |
| Ex-smoker | 819 (20.1%) | 2505 (20.5%) | 2074 (18.2%) | 4509 (19.8%) |
| Smoker | 468 (11.5%) | 1687 (13.8%) | 679 (6.0%) | 2638 (11.6%) |
| Unknown/Missing | 2 ( < 0.1%) | 54 (0.4%) | 14 (0.1%) | 63 (0.3%) |
| Body mass index | ||||
| Underweight | 90 (2.2%) | 337 (2.8%) | 176 (1.5%) | 451 (2.0%) |
| Healthy weight | 1411 (34.6%) | 4701 (38.5%) | 4324 (38%) | 8422 (37.0%) |
| Overweight | 1288 (31.6%) | 3551 (29.1%) | 3431 (30.2%) | 7044 (31.0%) |
| Obese/severely obese | 1203 (29.5%) | 3304 (27.0%) | 3183 (28%) | 6298 (27.7%) |
| Unknown/Missing | 82 (2.0%) | 329 (2.7%) | 265 (2.3%) | 543 (2.4%) |
aThe data presented related to Cohort 1: singleton pregnancies ending in a live or stillbirth at ≥20 + 0 gestation used for analyses of stillbirth and extended perinatal death outcomes. The exposed pregnancies included in Cohorts 2–10 differed slightly from those in Cohort 1, and the controls were redrawn for each cohort. Characteristics of Cohorts 2–10 therefore differ from those shown above, although differences were minimal.