| n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | n | % | P values | |
| BMI at booking appointment | 594 | 23.3 (4.6) | 3641 | 25.1 (5.4) | 4235 | 24.8 (5.3) | 356 | 7.8 | <0.001 |
| IMD score | 640 | 44.7 (18.0) | 3948 | 41.6 (17.9) | 4588 | 41.8 (17.9) | 3 | 0.1 | <0.001 |
| Number of weeks’ gestation at booking appointment | 640 | 12.1 (5.0) | 3951 | 11.4 (4.3) | 4246 | 12.4 (3.1) | 345 | 7.5 | <0.001 |
BMI, body mass index (kg/m²); GCSE, General certificate of secondary education; IMD, Index of multiple deprivation.