- Univariate and multivariate analyses of risk factors for singleton preterm births.
| Factors | Singleton preterm(n=15833) | Singleton term(n=199421) | OR (95% CI)* | P-value | aOR (95% CI) (Model A)† | P-value |
|---|---|---|---|---|---|---|
| Maternal age (years) | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | |
| <20 | 609 (3.8) | 4584 (2.3) | 1.796 (1.647–1.958) | <0.001 | 1.963 (1.796–2.145) | <0.001 |
| 20–34 | 13124 (82.9) | 177395 (89.0) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ≥35 | 2100 (13.3) | 17442 (8.7) | 1.627 (1.550–1.708) | <0.001 | 1.318 (1.250–1.390) | <0.001 |
| Parity | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| 1 | 9949 (62.8) | 140002 (70.2) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ≥2 | 5884 (37.2) | 59419 (29.8) | 1.393 (1.347–1.441) | <0.001 | 1.423 (1.372–1.476) | <0.001 |
| HDP | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 1007 (6.4) | 3486 (1.7) | 3.818 (3.552–4.103) | <0.001 | 3.978 (3.691–4.288) | <0.001 |
| No | 14826 (93.6) | 195935 (98.3) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| GDM | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 723 (4.6) | 7020 (3.5) | 1.311 (1.213–1.418) | <0.001 | 1.216 (1.122–1.319) | <0.001 |
| No | 15110 (95.4) | 192401 (96.5) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ICP | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 347 (2.2) | 973 (0.5) | 4.570 (4.039–5.172) | <0.001 | 5.520 (4.860–6.270) | <0.001 |
| No | 15486 (97.8) | 198448 (99.5) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Anemia | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 288 (1.8) | 2407 (1.2) | 1.516 (1.341–1.71) | <0.001 | 1.261 (1.108–1.436) | <0.001 |
| No | 15545 (98.2) | 199421 (98.2) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Chorioamnionitis | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | |
| Yes | 196 (1.2) | 787 (0.4) | 3.164 (2.703–3.703) | <0.001 | 2.834 (2.406–3.340) | <0.001 |
| No | 15637 (98.8) | 198634 (99.6) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Placenta previa | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 284 (1.8) | 392 (0.2) | 9.27 (7.95–10.81) | <0.001 | 10.09 (8.60–11.83) | <0.001 |
| No | 15549 (98.2) | 199029 (99.8) | 1.00 | #x00A0; | 1.00 | #x00A0; |
| Placental abruption | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | |
| Yes | 96 (0.6) | 66 (0.0) | 18.42 (13.46–25.21) | <0.001 | 17.20 (12.35–23.95) | <0.001 |
| No | 15737 (99.4) | 199355 (100.0) | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Fetal distress | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 832 (5.3) | 8018 (4.0) | 1.324 (1.230–1.425) | <0.001 | 1.249 (1.157–1.348) | <0.001 |
| No | 15001 (94.7) | 191403 (96.0) | 1.000 | #x00A0; | 1.000 | #x00A0; |
Values are presented as number and percentages (%).
↵* OR (odds ratio) value and 95% CI (confidence interval) of univariate logistic analysis model, p<0.05 was considered significant. †aOR (adjusted odds ratio) value and 95% CI after adjusting for other confounders in Model A (including maternal age, parity, HDP, GDM, ICP, anemia, chorioamnionitis, placenta previa, placental abruption, and fetal distress); p<0.05 was considered significant. HDP: hypertension disorders in pregnancy, ICP: intrahepatic cholestasis of pregnancy, GDM: gestational diabetes mellitus