Table 1.
Demographics and clinical characteristics of the subjects
| Characteristic | Value n (%) |
|---|---|
| Pregnancy characteristics (n = 309) | |
| Maternal age (years) | |
| <25 | 134 (43.4) |
| 25–30 | 118 (38.2) |
| >30 | 57 (18.4) |
| BMI index before pregnancy (kg/m2) | |
| <18.5 | 58 (18.8) |
| 18.5–24.9 | 218 (70.6) |
| ≥25 | 33 (10.6) |
| Monthly income of the family (RMB) | |
| <3,500 | 75 (24.3) |
| 3,500–4,500 | 177 (57.3) |
| >4,500 | 57 (18.4) |
| Gravidity | |
| Primigravida | 101 (32.7) |
| Multigravida | 208 (67.3) |
| Parity | |
| Nulliparous | 199 (64.4) |
| Multiparous | 110 (35.6) |
| Education | |
| Primary school or lower | 15 (4.9) |
| Secondary school | 214 (69.3) |
| University or above | 80 (25.8) |
| Employment | |
| No | 217 (70.2) |
| Yes | 92 (29.8) |
| Passive smoking exposure | |
| No | 108 (35.0) |
| Yes | 201 (65.0) |
| Neonate characteristics (n = 253) | |
| Birth length | 50.3 ± 1.4* |
| Head circumference | 33.9 ± 0.9* |
| Birth weight (g) | 3,310.0 ± 413.0* |
| LBW | 7 (2.8) |
| SGA | |
| <10th percentile | 17 (6.8) |
| LGA | |
| >90th percentile | 15 (6.0) |
| Preterm | |
| <37 weeks | 16 (6.3) |
*Data were shown as the mean ± SD.