Table 1.
Characteristics of the covariates according to outcome status of preterm birth and preterm mortality
| Number of live birth | Number of preterm birth | Number of deaths due to prematurity | Preterm birth rate (%) | Preterm mortality rate (‰) | |
|---|---|---|---|---|---|
| Number of participants | 818481 | 76923 | 2248 | 9.40 | 2.75 |
| Maternal age (years) | |||||
| <35 | 580486 | 27693 | 961 | 4.77 | 1.66 |
| 35+ | 237995 | 49230 | 1287 | 20.69 | 5.41 |
| Gestational week (weeks) | |||||
| <34 | 189486 | 23077 | 1753 | 12.18 | 9.25 |
| 34+ | 628995 | 53846 | 495 | 8.56 | 0.79 |
| Birth weight (kg) | |||||
| <2.5 | 344491 | 43994 | 1674 | 12.77 | 4.86 |
| 2.5+ | 473990 | 32929 | 574 | 6.95 | 1.21 |
| Pregnancy parity | |||||
| 1 | 94901 | 43808 | 1471 | 46.16 | 15.50 |
| 1+ | 723580 | 33115 | 777 | 4.58 | 1.07 |
| Birth parity | |||||
| 1 | 61375 | 31638 | 987 | 51.55 | 16.08 |
| 1+ | 757106 | 45285 | 1261 | 5.98 | 1.67 |
| Assisted reproductive technology (Yes) | |||||
| Yes | 30959 | 23469 | 756 | 75.81 | 24.40 |
| No | 787522 | 53454 | 1492 | 6.79 | 1.90 |
| Income (USD/month) | |||||
| <500 | 418798 | 50392 | 1577 | 12.03 | 3.76 |
| 500+ | 399683 | 26531 | 671 | 6.64 | 1.68 |
| Education | |||||
| College | 74060 | 3315 | 68 | 4.48 | 0.91 |
| Other | 744421 | 73608 | 2180 | 9.89 | 2.93 |
| Residence | |||||
| Urban | 350154 | 45300 | 1123 | 12.94 | 3.21 |
| Rural | 468327 | 31623 | 1125 | 6.75 | 2.40 |
| Newborn Emergency Transport Service | |||||
| Yes | 12755 | 5562 | 48 | 43.60 | 3.75 |
| No | 805726 | 71361 | 2200 | 8.86 | 2.73 |
| Infant gender | |||||
| Male | 415496 | 44346 | 1348 | 10.67 | 3.24 |
| Female | 402985 | 32577 | 900 | 8.08 | 2.23 |
| Occupation | |||||
| Office job | 447921 | 20562 | 477 | 4.59 | 1.07 |
| Other | 370560 | 56361 | 1771 | 15.21 | 4.78 |
| Single birth | |||||
| Yes | 787168 | 73715 | 2229 | 9.36 | 2.83 |
| No | 31313 | 3208 | 19 | 10.24 | 0.60 |