Table 1. Characteristics of mothers and children, by selected birth weight cohort (n = 210 172).
| Characteristics | Selected birth weight cohorts | ||
| <2500 g (n = 3911) |
3000 to 3249 g (n = 57 885) |
≥4250 g (n = 3048) |
|
| Mother | |||
| Age at delivery (y) | 24.5 (3.1) | 24.7 (3.2) | 25.7 (3.6) |
| Height (m) | 1.57 (0.05) | 1.59 (0.04) | 1.61 (0.05) |
| Weight at first prenatal visit (kg) | 49.8 (6.1) | 51.5 (6.0) | 56.5 (7.3) |
| Body mass index (kg/m2) | 20.2 (2.3) | 20.5 (2.2) | 21.8 (2.6) |
| Residence in southern area (%) | 94.4 | 85.7 | 95.1 |
| Han ethnicity (%) | 98.8 | 99.1 | 99.4 |
| Farmer (%) | 60.7 | 64.2 | 62.4 |
| Education | |||
| High school or above (%) | 8.6 | 10.1 | 10.7 |
| Middle school (%) | 58.3 | 61.5 | 59.0 |
| Primary school or less (%) | 33.2 | 28.4 | 30.4 |
| Folic acid supplementation before or during pregnancy (%) |
51.1 | 55.3 | 50.3 |
| Primiparous (%) | 86.7 | 85.1 | 71.0 |
| Child | |||
| Gestational age (weeks) | 37.0 (2.9) | 39.4 (1.7) | 40.2 (1.5) |
| Male (%) | 44.3 | 46.8 | 69.0 |
| Birth length (cm) | 46.3 (3.2) | 49.3 (1.9) | 51.5 (2.5) |
| Age at follow-up visit (months) | 60.2 (8.4) | 59.1 (8.2) | 58.8 (8.1) |