Characteristics of groups consenting or not consenting to collection of Key Stage 1 (KS1) data from child's school
| Consent to KS1 data being collected | Contact made but no consent | |
|---|---|---|
| Number of women | 1776 (100%) | 1418 (100%) |
| Maternal age at trial entry (years, median (IQR)) | 27.3 (23.3–31.5) | 25.0 (21.4–29.0) |
| Gestation age at trial entry (days, median (IQR)) | 219 (201–232) | 219 (201–232) |
| Multiple births | 131 (7.4%) | 79 (5.6%) |
| Number of children | 1899 (100%) | 1493 (100%) |
| Delivery within 48 h of trial entry | 241 (12.7%) | 125 (8.4%) |
| Delivery within 7 days of trial entry | 339 (17.9%) | 189 (12.7%) |
| Gestational age at delivery (days, median (IQR)) | 265 (242–277) | 268 (249–279) |
| Birth weight (g, median (IQR)) | 2920 (2210–3400) | 2940 (2350–3390) |
| Males | 1018 (53.6%) | 786 (52.6%) |
| Admission to neonatal unit | 588 (31.0%) | 390 (26.1%) |
| Ventilated | 185 (9.7%) | 105 (7.0%) |
| Respiratory distress syndrome | 202 (10.6%) | 121 (8.1%) |
| Oxygen at 28 days | 91 (4.8%) | 57 (3.8%) |
| Positive blood culture | 40 (2.1%) | 31 (2.1%) |
| Necrotising enterocolitis (suspected or proven) | 19 (1.0%) | 15 (1.0%) |
| Abnormal cerebral ultrasonography | 28 (1.5%) | 20 (1.3%) |
| Social deprivation: number (%) in lowest quartile | ||
| Income | 910 (47.9%) | 898 (60.1%) |
| Education | 854 (45.0%) | 846 (56.7%) |
| Child poverty | 884 (46.6%) | 877 (58.7%) |
| Ethnicity | 1546 (100%) | 1693 (100%) |
| White | 1449 (93.7%) | 1311 (77.4%) |
Numbers (%) except where otherwise indicated (In two cases not tabulated, no contact was made with parents/carers to seek consent).