Table 1.
General characteristics of the study population
| N | Preterm n(%) 206 (100) |
Term n(%) 412 (100) |
P a value |
|---|---|---|---|
| Maternal age (years) [mean ± SD] | 28.35 ± 5.32 | 28.25 ± 4.70 | 0.808 |
| Maternal age (years) | 0.732 | ||
| < 25 | 47 (22.8) | 99 (24.0) | |
| 25–34 | 130 (63.1) | 264 (64.1) | |
| ≥ 35 | 29 (14.1) | 49 (11.9) | |
| Neonatal gender | 1.000 | ||
| Male | 121 (58.7) | 242 (58.7) | |
| Female | 85 (41.3) | 170 (41.3) | |
| Gestational age at blood sampling (weeks) | 1.000 | ||
| < 14 | 68 (33.0) | 136 (33.0) | |
| 14–27 | 116 (56.3) | 232 (56.3) | |
| ≥ 28 | 22 (10.7) | 44 (10.7) | |
| pre pregnancy BMI b | 0.060 | ||
| < 18.5 | 60 (29.6) | 98 (24.0) | |
| 18.5–23.9 | 120 (59.1) | 280 (68.4) | |
| ≥ 24.0 | 23 (11.3) | 31 (7.6) | |
| Literacy | 0.647 | ||
| Primary | 7 (3.4) | 18 (4.4) | |
| Secondary | 122 (59.5) | 255 (61.9) | |
| Graduate and above | 76 (37.1) | 139 (33.7) | |
| Household yearly income (yuan) | 0.747 | ||
| < 50,000 | 94 (45.6) | 197 (47.8) | |
| ≥ 50,000 | 71 (34.5) | 143 (34.7) | |
| Unclear | 41 (19.9) | 72 (17.5) | |
| Parity | 0.586 | ||
| Nullipara | 124 (60.8) | 241 (58.5) | |
| Multipara | 80 (39.2) | 171 (41.5) | |
| Abortions | 0.610 | ||
| 0 | 101 (49.5) | 195 (47.3) | |
| ≥ 1 | 103 (50.5) | 217 (52.7) | |
| Second-hand smoking | 0.930 | ||
| Yes | 25 (12.1) | 49 (11.9) | |
| No | 181 (87.9) | 363 (88.1) | |
| Maternal reproductive tract infection | 0.935 | ||
| Yes | 29 (14.1) | 59 (14.3) | |
| No | 178 (85.9) | 353 (85.7) |
a P values were determined by using the chi-square test
b BMI body mass index;