Table 1.
Characteristics of healthy women without additional risk factors by maternal BMI category
| Underweight n = 577 | Normal weight n = 8936 | Overweight n = 4778 | Obese n = 1955 | Very obese n = 984 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | n | % | |
| Maternal age (years) | ||||||||||
| Mean [SD] | 25.4 | [5.6] | 28.0 | [6.0] | 28.8 | [5.9] | 28.2 | [5.8] | 28.1 | [5.9] |
| Under 20 | 96 | 16.6 | 763 | 8.5 | 270 | 5.7 | 120 | 6.1 | 53 | 5.4 |
| 20–24 | 182 | 31.5 | 1934 | 21.6 | 934 | 19.5 | 463 | 23.7 | 266 | 27.0 |
| 25–29 | 153 | 26.5 | 2575 | 28.8 | 1430 | 29.9 | 564 | 28.8 | 287 | 29.2 |
| 30–34 | 106 | 18.4 | 2300 | 25.7 | 1234 | 25.8 | 500 | 25.6 | 212 | 21.5 |
| 35–39 | 39 | 6.8 | 1134 | 12.7 | 754 | 15.8 | 255 | 13.0 | 126 | 12.8 |
| 40+ | 1 | 0.2 | 223 | 2.5 | 153 | 3.2 | 50 | 2.6 | 37 | 3.8 |
| Missing | 0 | 0.0 | 7 | 0.1 | 3 | 0.1 | 3 | 0.2 | 3 | 0.3 |
| Ethnic group | ||||||||||
| White | 451 | 78.2 | 7298 | 81.7 | 3894 | 81.5 | 1630 | 83.4 | 863 | 87.7 |
| Indian | 21 | 3.6 | 213 | 2.4 | 94 | 2.0 | 26 | 1.3 | 7 | 0.7 |
| Pakistani | 23 | 4.0 | 294 | 3.3 | 182 | 3.8 | 65 | 3.3 | 20 | 2.0 |
| Bangladeshi | 20 | 3.5 | 150 | 1.7 | 82 | 1.7 | 18 | 0.9 | 3 | 0.3 |
| Black Caribbean | 9 | 1.6 | 107 | 1.2 | 84 | 1.8 | 24 | 1.2 | 22 | 2.2 |
| Black African | 7 | 1.2 | 239 | 2.7 | 187 | 3.9 | 93 | 4.8 | 40 | 4.1 |
| Mixed | 10 | 1.7 | 134 | 1.5 | 74 | 1.5 | 30 | 1.5 | 15 | 1.5 |
| Other | 35 | 6.1 | 488 | 5.5 | 180 | 3.8 | 64 | 3.3 | 13 | 1.3 |
| Missing | 1 | 0.2 | 13 | 0.1 | 1 | 0.0 | 5 | 0.3 | 1 | 0.1 |
| Understanding of English | ||||||||||
| Fluent | 495 | 85.8 | 8148 | 91.2 | 4387 | 91.8 | 1839 | 94.1 | 958 | 97.4 |
| Some | 56 | 9.7 | 567 | 6.3 | 253 | 5.3 | 80 | 4.1 | 19 | 1.9 |
| None | 21 | 3.6 | 180 | 2.0 | 112 | 2.3 | 25 | 1.3 | 6 | 0.6 |
| Missing | 5 | 0.9 | 41 | 0.5 | 26 | 0.5 | 11 | 0.6 | 1 | 0.1 |
| Marital/partner status | ||||||||||
| Married/Living together | 480 | 83.2 | 7708 | 86.3 | 4208 | 88.1 | 1691 | 86.5 | 826 | 83.9 |
| Single/Unsupported by partner | 91 | 15.8 | 1073 | 12.0 | 490 | 10.3 | 226 | 11.6 | 142 | 14.4 |
| Missing | 6 | 1.0 | 155 | 1.7 | 80 | 1.7 | 38 | 1.9 | 16 | 1.6 |
| Index of Multiple Deprivation quintiles | ||||||||||
| 1st Least deprived | 57 | 9.9 | 1467 | 16.4 | 719 | 15.0 | 247 | 12.6 | 124 | 12.6 |
| 2nd | 85 | 14.7 | 1725 | 19.3 | 834 | 17.5 | 317 | 16.2 | 148 | 15.0 |
| 3rd | 102 | 17.7 | 1696 | 19.0 | 913 | 19.1 | 337 | 17.2 | 173 | 17.6 |
| 4th | 145 | 25.1 | 1811 | 20.3 | 976 | 20.4 | 454 | 23.2 | 229 | 23.3 |
| 5th Most deprived | 184 | 31.9 | 2182 | 24.4 | 1293 | 27.1 | 588 | 30.1 | 297 | 30.2 |
| Missing | 4 | 0.7 | 55 | 0.6 | 43 | 0.9 | 12 | 0.6 | 13 | 1.3 |
| Previous pregnancies ≥24 weeks | ||||||||||
| 0 Nulliparous | 344 | 59.6 | 5005 | 56.0 | 2420 | 50.6 | 945 | 48.3 | 418 | 42.5 |
| 1 previous | 168 | 29.1 | 2602 | 29.1 | 1431 | 29.9 | 590 | 30.2 | 297 | 30.2 |
| 2 previous | 43 | 7.5 | 834 | 9.3 | 545 | 11.4 | 242 | 12.4 | 164 | 16.7 |
| 3+ previous | 22 | 3.8 | 484 | 5.4 | 371 | 7.8 | 174 | 8.9 | 104 | 10.6 |
| Missing | 0 | 0.0 | 11 | 0.1 | 11 | 0.2 | 4 | 0.2 | 1 | 0.1 |
| Gestation (completed weeks) | ||||||||||
| Mean [SD] | 39.5 | [1.2] | 39.7 | [1.1] | 39.8 | [1.1] | 39.9 | [1.1] | 39.9 | [1.1] |
| 37 | 37 | 6.4 | 351 | 3.9 | 160 | 3.3 | 51 | 2.6 | 23 | 2.3 |
| 38 | 79 | 13.7 | 860 | 9.6 | 489 | 10.2 | 149 | 7.6 | 88 | 8.9 |
| 39 | 167 | 28.9 | 2138 | 23.9 | 1046 | 21.9 | 388 | 19.8 | 219 | 22.3 |
| 40 | 179 | 31.0 | 3219 | 36.0 | 1660 | 34.7 | 699 | 35.8 | 323 | 32.8 |
| 41 | 98 | 17.0 | 2139 | 23.9 | 1268 | 26.5 | 599 | 30.6 | 297 | 30.2 |
| 42–44 | 16 | 2.8 | 210 | 2.4 | 144 | 3.0 | 62 | 3.2 | 33 | 3.4 |
| Missing | 1 | 0.2 | 19 | 0.2 | 11 | 0.2 | 7 | 0.4 | 1 | 0.1 |
| Birthweight (grams) | ||||||||||
| Mean [SD] | 3202 | [421.1] | 3418 | [447.1] | 3505 | [467.4] | 3573 | [478.4] | 3594 | [467.5] |
| >2500 | 24 | 4.2 | 128 | 1.4 | 59 | 1.2 | 18 | 0.9 | 5 | 0.5 |
| 2500–2999 | 153 | 26.5 | 1394 | 15.6 | 566 | 11.8 | 204 | 10.4 | 81 | 8.2 |
| 3000–3499 | 267 | 46.3 | 3690 | 41.3 | 1792 | 37.5 | 642 | 32.8 | 339 | 34.5 |
| 3500–3999 | 110 | 19.1 | 2819 | 31.5 | 1667 | 34.9 | 722 | 36.9 | 363 | 36.9 |
| 4000–4499 | 17 | 2.9 | 784 | 8.8 | 582 | 12.2 | 310 | 15.9 | 163 | 16.6 |
| ≥4500 | 5 | 0.9 | 106 | 1.2 | 105 | 2.2 | 53 | 2.7 | 32 | 3.3 |
| Missing | 1 | 0.2 | 15 | 0.2 | 7 | 0.1 | 6 | 0.3 | 1 | 0.1 |