Description of the study population (percentages)
| Characteristics | Maternal limiting longstanding illness | |
|---|---|---|
| Yes (n=1130*) | No (n=10 569*) | |
| Per cent (95% CI) | Per cent (95% CI) | |
| Maternal characteristics | ||
| Age at delivery in years (p=0.052) | ||
| <25 | 26.3 (23.3 to 29.6) | 23.1 (21.6 to 24.8) |
| 25–34 | 52.9 (49.5 to 56.3) | 57.0 (55.7 to 58.3) |
| 35+ | 20.7 (18.2 to 23.5) | 19.8 (18.5 to 21.3) |
| Ethnic group (p=0.942) | ||
| White | 89.1 (85.7 to 91.7) | 89.2 (86.7 to 91.2) |
| Other ethnic group | 10.9 (8.3 to 14.3) | 10.8 (8.8 to 13.3) |
| Qualification (p<0.001) | ||
| Higher degree/first degree/diploma | 18.9 (16.4 to 21.6) | 26.7 (24.6 to 28.9) |
| A/AS/S levels | 9.0 (7.3 to 11.0) | 9.5 (8.9 to 10.2) |
| O level/GCSE grades A–C | 36.6 (33.3 to 39.9) | 35.6 (33.9 to 37.3) |
| GCSE grades D–G | 12.7 (10.5 to 15.4) | 10.6 (9.6 to 11.6) |
| Other academic qualifications (including overseas) | 1.9 (1.2 to 3.1) | 2.2 (1.8 to 2.7) |
| None of these qualifications | 21.0 (18.4 to 23.7) | 15.4 (14.1 to 16.9) |
| Socioeconomic class (p<0.001) | ||
| Managerial/professional occupation | 29.4 (17.9 to 23.0) | 20.3 (28.4 to 32.4) |
| Intermediate occupation | 18.0 (15.4 to 21.0) | 22.3 (21.2 to 23.4) |
| Routine/manual occupation | 50.0 (46.5 to 53.5) | 39.6 (37.6 to 41.7) |
| Never worked/long-term unemployed | 11.7 (9.5 to 14.2) | 7.7 (6.6 to 9.0) |
| Pregnancy characteristics | ||
| Whether this was the first baby (p=0.005) | ||
| No | 62.2 (58.6 to 65.6) | 57.0 (55.8 to 58.3) |
| Yes | 37.8 (34.4 to 41.4) | 43.0 (41.7 to 44.2) |
| Planning pregnancy (p<0.001) | ||
| Pregnancy was a surprise | 52.8 (49.4 to 56.2) | 43.0 (41.6 to 44.3) |
| Planned to get pregnant | 47.2 (43.8 to 50.6) | 57.0 (55.7 to 58.4) |
| Mother's smoking status during pregnancy (p<0.001) | ||
| None/gave up | 69.0 (65.3 to 72.5) | 78.4 (76.9 to 79.7) |
| Kept smoking | 31.0 (27.5 to 34.7) | 21.6 (20.3 to 23.1) |
| Child characteristics | ||
| Sex (p=0.455) | ||
| Male | 49.8 (46.1 to 53.5) | 51.2 (50.1 to 52.4) |
| Female | 50.2 (46.5 to 53.9) | 48.8 (47.6 to 49.9) |
| Gestational age (p<0.001) | ||
| Very preterm <32 weeks | 1.2 (0.7 to 2.2) | 0.8 (0.6 to 1.0) |
| Preterm 32–36 weeks | 9.9 (7.9 to 12.4) | 5.7 (5.2 to 6.3) |
| Term 37–42 weeks | 88.9 (86.1 to 91.2) | 93.5 (92.9 to 94.1) |
| Mean birth weight in grams (p<0.001) | 3309 (3268 to 3350) | 3383 (3369 to 3397) |
| Duration of breast feeding (p<0.001) | ||
| Never breast fed | 35.1 (31.9 to 38.4) | 32.1 (30.2 to 34.1) |
| <1 week | 11.4 (9.5 to 13.8) | 9.7 (9.0 to 10.5) |
| 1 week—3 months | 28.5 (25.7 to 31.5) | 25.2 (24.2 to 26.3) |
| > 3 months | 25.0 (22.0 to 28.2) | 32.9 (30.8 to 35.1) |
| Child had a limiting longstanding illness at 7 years of age (p<0.001) | ||
| No | 88.1 (85.6 to 90.2) | 94.0 (93.4 to 94.5) |
| Yes | 11.9 (9.8 to 14.4) | 6.0 (5.5 to 6.6) |
| Poverty | ||
| Income poverty (p<0.001) | ||
| Family income above 60% of the national median | 57.7 (53.8 to 61.6) | 70.7 (68.8 to 72.6) |
| Family income below 60% of the national median | 42.3 (38.4 to 46.2) | 29.3 (27.4 to 31.2) |
| Subjective poverty (p<0.001) | ||
| Subjectively not poor | 45.8 (42.2 to 49.5) | 63.2 (61.6 to 64.8) |
| Subjectively poor | 54.2 (50.5 to 57.8) | 36.8 (35.2 to 38.4) |
*Weighted numbers.
GCSE, General Certificate of Secondary Education.