Table 1.
Maternal and newborn characteristics of the Generation R Study Population
| (n=6034) | Spring | Summer | Autumn | Winter |
|---|---|---|---|---|
| Maternal characteristics | ||||
| Age, years | 30.7 (5.1) | 30.3 (5.2) | 30.7 (5.0) | 30.6 (5.2) |
| National origin (%) | ||||
| Dutch | 52.3 | 53.0 | 55.3 | 54.3 |
| Other Western | 12.4 | 10.9 | 11.1 | 11.2 |
| Non-Western | 35.3 | 36.1 | 33.5 | 34.5 |
| Parity (% primiparous) | 51.4 | 55.0 | 57.3 | 53.6 |
| Educational level (%) | ||||
| Primary | 10.9 | 10.0 | 4.8 | 10.1 |
| Secondary | 39.5 | 40.3 | 39.5 | 41.3 |
| High | 49.6 | 49.7 | 49.7 | 48.6 |
| Smoking during pregnancy (%) | ||||
| Never | 78.4 | 77.2 | 75.4 | 75.6 |
| Until pregnancy was recognised | 7.1 | 8.1 | 7.1 | 9.0 |
| Continued | 14.5 | 14.6 | 17.4 | 15.2 |
| Mode of delivery (%) | ||||
| Spontaneous | 69.1 | 70.3 | 67.8 | 72.5 |
| Instrumental | 17.5 | 16.0 | 18.9 | 16.4 |
| Caesarean section | 13.4 | 13.7 | 13.3 | 11.1 |
| Child characteristics | ||||
| Gender (% boys) | 51.4 | 49.0 | 51.0 | 51.8 |
| Birth weight, kg | 3.4 (5.7) | 3.4 (5.8) | 3.4 (5.5) | 3.4 (5.8) |
| Gestational age at birth, weeks (median, IQR) | 40.0 (1.9) | 40.1 (2.0) | 40.1 (2.0) | 40.0 (2.0) |
Values represent means (SD) unless otherwise indicated.