Characteristics of study cohort
| Mean | SD | Range | |
| Maternal age (years) | 30.3 | 3.8 | 20.8–38.5 |
| Maternal BMI before pregnancy | 25.4 | 4.8 | 16.2–48.9 |
| Infant birth weight (g) | 3495 | 478 | 1676–5296 |
| Infant head circumference (cm) | 35.0 | 1.3 | 30.0–38.7 |
| Infant abdominal circumference (cm) | 33.5 | 1.7 | 25.9–39.4 |
| No (%) | |
| Female baby | 621 (47) |
| Mother consumed ⩾14 units of alcohol per week before pregnancy | 267 (20) |
| Mother smoked before pregnancy | 349 (26) |
| Maternal educational level | |
| No qualifications | 21 (2) |
| CSE or equivalent | 115 (9) |
| O level or equivalent | 386 (29) |
| A level or equivalent | 398 (30) |
| HND or equivalent | 109 (8) |
| Degree | 294 (22) |
| Primiparous | 710 (54) |
| Mother worked at 11 weeks of gestation | 1318 (99) |
| Mother worked at 19 weeks of gestation | 1287 (97) |
| Mother worked at 34 weeks of gestation | 797 (60) |
| Preterm delivery | 46 (3) |
| Small for gestational age | 89 (7) |
| Small head circumference | 132 (10) |
| Small abdominal circumference | 131 (10) |
BMI, bodymass index.