Table 5.
Logistics regression to identify potential risk factors for preterm birth before 32 weeks (total N = 3,288).
| Variables | PTB before 32 weeks (n = 341) | After 32 weeks (n = 2,947) | P-value | Multivariate analysis | ||
|---|---|---|---|---|---|---|
| OR | 95% CI | P-value | ||||
| Age (y)* | 0.007 | 0.010 | ||||
| <25 | 32 (9.4%) | 154 (5.2%) | 1.964 | 1.265–3.048 | 0.003 | |
| 25–34 | 244 (71.6%) | 2,184 (74.1%) | Ref. | |||
| ≥35 | 65 (19.1%) | 609 (20.7%) | 1.006 | 0.735–1.377 | 0.970 | |
| Parity* | 0.073 | |||||
| Nulli | 205 (60.1%) | 1,917 (65.0%) | ||||
| Pluri | 136 (39.9%) | 1,030 (35.0%) | ||||
| PTB histroy | 0.841 | |||||
| Yes | 8 (2.3%) | 60 (2.0%) | ||||
| No | 333 (97.7%) | 2,887 (98.0%) | ||||
| Conception | 0.350 | |||||
| Natural | 214 (62.8%) | 1,768 (60.0%) | ||||
| ART | 127 (37.2%) | 1,179 (40.0%) | ||||
| Choronicity* | <0.001 | |||||
| Dichorionic | 185 (54.3%) | 2,249 (76.3%) | Ref. | |||
| Monochorionic | 156 (45.7%) | 698 (23.7%) | 2.566 | 1.991–3.307 | <0.001 | |
| Height (cm)* | 0.013 | |||||
| <160 | 112 (36.1%) | 860 (30.3%) | ||||
| 160–169 | 194 (62.6%) | 1,869 (65.9%) | ||||
| ≥170 | 4 (1.3%) | 109 (3.8%) | ||||
| Pre BMI (kg/m2) | 0.735 | |||||
| <18.5 | 51 (17.6%) | 438 (16.3%) | ||||
| 18.5–23.9 | 183 (63.1%) | 1,787 (66.4%) | ||||
| 24.0–27.9 | 44 (15.2%) | 370 (13.7%) | ||||
| ≥28.0 | 12 (4.1%) | 97 (3.6%) | ||||
| Weight Gain (kg)* | <0.001 | <0.001 | ||||
| <10 | 55 (18.5%) | 134 (4.9%) | 4.319 | 2.931–6.364 | <0.001 | |
| 10–14.9 | 78 (26.3%) | 518 (19.1%) | 1.476 | 1.073–2.030 | 0.017 | |
| 15–19 | 104 (35.0%) | 1,041 (38.4%) | Ref. | |||
| ≥20 | 60 (20.2%) | 1,017 (37.5%) | 0.558 | 0.400–0.779 | 0.001 | |
| HDP* | 0.034 | |||||
| No | 305 (89.4%) | 2,567 (87.1%) | ||||
| GH | 4 (1.2%) | 5 (0.2%) | ||||
| HTN | 2 (0.6%) | 101 (3.4%) | ||||
| PE | 30 (8.8%) | 274 (9.3%) | ||||
| ICP* | 0.097 | |||||
| Yes | 14 (4.1%) | 192 (6.5%) | 0.533 | 0.295–0.964 | 0.037 | |
| No | 327 (95.9%) | 2,755 (93.5%) | Ref. | |||
*
Factors assigned to multivariate logistic regression analysis.
Ref., reference; PTB, preterm birth; ART, assistant reproductive technology; BMI, body mass index; HDP, hypertensive disorders of pregnancy; HTN, hypertension; GH, gestational hypertension; PE, preeclampsia; ICP, intrahepatic cholestasis of pregnancy.