Risk factors associated with each spontaneous preterm subgroup compared to the term group in multinomial multivariate logistic regression analysis.
| #x00A0; | <32 weeks | #x00A0; | 32–33 weeks | #x00A0; | 34–36 weeks | #x00A0; |
|---|---|---|---|---|---|---|
| Factors | aOR (95% CI)* | P-value | aOR (95% CI)* | P-value | aOR (95% CI)* | P-value |
| Maternal age (years) | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| <20 | 1.088 (0.757–1.564) | 0.649 | 1.328 (1.004–1.756) | 0.047 | 0.950 (0/868–1.163) | 0.950 |
| 20–34 | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ≥35 | 1.585 (1.357–1.851) | <0.001 | 1.299 (1.127–1.498) | <0.001 | 1.252 (1.166–1.343) | <0.001 |
| Parity | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| 1 | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ≥2 | 1.391 (1.237–1.563) | <0.001 | 1.391 (1.258–1.453) | <0.001 | 1.218 (1.161–1.278) | <0.001 |
| HDP | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 8.518 (7.099–10.221) | <0.001 | 7.924 (6.797–1.538) | <0.001 | 4.303(3.917–4.727) | <0.001 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| GDM | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 1.185 (0.922–1.523) | 0.184 | 1.293 (1.047–1.596) | 0.017 | 1.286 (1.162–1.424) | <0.001 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| ICP | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 1.384 (0.766–2.499) | 0.282 | 3.875 (2.595–5.786) | <0.001 | 10.04(8.79–11.47) | <0.001 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Anemia | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 1.240 (0.896–1.715) | 0.195 | 1.862 (1.392–2.489) | 0.001 | 1.221 (1.027–1.452) | 0.240 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Chorioamnionitis | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 33.30 (27.29–40.63) | <0.001 | 3.863 (2.620–5.694) | <0.001 | 1.835 (1.405–2.397) | <0.001 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
| Placenta previa | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 36.75 (26.02–51.92) | <0.001 | 22.71 (16.36–31.517) | <0.001 | 16.05 (13.29–19.36) | <0.001 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.00 | #x00A0; |
| Placental abruption | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 63.75 (37.49–108.4) | <0.001 | 49.59 (30.66–80.21) | <0.001 | 17.31 (11.76–25.48) | <0.001 |
| No | 1.000 | #x00A0; | 1.00 | #x00A0; | 1.00 | #x00A0; |
| Fetal distress | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; | #x00A0; |
| Yes | 1.735 (1.414–2.130) | <0.001 | 1.654 (1.378–1.986) | <0.001 | 1.016 (1.050–1.286) | 0.004 |
| No | 1.000 | #x00A0; | 1.000 | #x00A0; | 1.000 | #x00A0; |
↵* aOR (adjusted odds ration) value and 95% CI (confidence interval) after adjusting for other confounders in Model B (including maternal age, parity, HDP, GDM, ICP, anemia, chorioamnionitis, placenta previa, placental abruption, and fetal distress); the reference group was the term group. P<0.05 was considered significant. Bold values are significant. HDP: hypertension disorders in pregnancy, ICP: intrahepatic cholestasis of pregnancy, GDM: gestational diabetes mellitus