Table 1.
Baseline characteristics of all infants.
| n | Constituent ratio (%) | |
|---|---|---|
| Total | 536,008 | 100.0 |
| SEX | ||
| Boy | 282,261 | 52.7 |
| Girl | 253,729 | 47.3 |
| Unknown | 18 | 0.0 |
| NUMBER OF FETUSES | ||
| Single pregnancy | 531,826 | 99.2 |
| Twin pregnancies | 4,153 | 0.8 |
| Multiple pregnancies | 29 | 0.0 |
| REGION | ||
| Urban | 287,296 | 53.6 |
| Suburban and rural | 248,531 | 46.4 |
| Unknown | 181 | 0.0 |
| BIRTH WEIGHT | ||
| ≥2,500 g | 515,972 | 96.3 |
| 2,500 g> birth weight ≥2,000 g | 13,702 | 2.6 |
| 2,000 g> birth weight ≥1,500 g | 3,799 | 0.7 |
| <1,500 g | 1,539 | 0.3 |
| Unknown | 996 | 0.2 |
| GESTATIONAL WEEK | ||
| Full term (≥37 weeks) | 504,984 | 94.2 |
| Premature (<37 weeks) | 26,107 | 4.9 |
| Unknown | 4,917 | 0.9 |