Table 1.
Characteristics of the sample (N=13,539 pregnancies).
| n | % | |
|---|---|---|
| Ethnicity | ||
| Pakistani | 5071 | 37.5 |
| White British | 4425 | 32.7 |
| Other | 1725 | 12.7 |
| Missing | 2318 | 17.1 |
| Maternal age (years) | ||
| Mean (SD) | 27.31 (5.6) | |
| Missing | 1345 | 9.9 |
| Multiple pregnancy | ||
| Singleton | 13004 | 96.1 |
| Multiple pregnancy (twins or triplets) | 155 | 1.1 |
| Missing | 380 | 2.8 |
| Maternal education | ||
| Less than 5 GCSE equivalents | 2413 | 17.8 |
| 5 GCSE equivalents | 3451 | 25.5 |
| A level equivalents | 1622 | 12.0 |
| Higher than A level | 2870 | 21.2 |
| Other | 859 | 6.3 |
| Missing | 2324 | 17.2 |
| Pre-pregnancy BMI | ||
| Mean (SD) | 26.03 (5.7) | |
| Missing | 3167 | 23.4 |
| Obstetric complication (pre-eclampsia and/or gestational hypertension) | ||
| Yes | 763 | 5.6 |
| No | 11820 | 87.3 |
| Missing | 956 | 7.1 |
| Maternal tobacco smoking in pregnancy | ||
| Yes | 1847 | 13.6 |
| No | 9377 | 69.3 |
| Missing | 2315 | 17.1 |
| Preconception CMD | ||
| Yes | 2119 | 15.7 |
| No | 10099 | 74.6 |
| Missing | 1321 | 9.8 |
| Antenatal CMD | ||
| Yes | 1423 | 10.5 |
| No | 11916 | 88.0 |
| Missing | 200 | 1.5 |
| GDM | ||
| Yes | 1028 | 7.6 |
| No | 12044 | 89.0 |
| Missing | 467 | 3.5 |