Table 3.
Logistics regression to identify potential risk factors for preterm birth before 37 weeks (N = 3,288).
| Variables | PTB before 37weeks (n = 2,043) | Term after 37 weeks (n = 1,245) | P-value | Multivariate analysis | ||
|---|---|---|---|---|---|---|
| OR | 95% CI | P-value | ||||
| Age (y)* | 0.050 | |||||
| <25 | 129 (6.3%) | 57 (4.6%) | ||||
| 25–34 | 1,484 (72.6%) | 944 (75.8%) | ||||
| ≥35 | 430 (21.0%) | 244 (19.6%) | ||||
| Parity* | 0.189 | |||||
| Nulli | 1,301 (63.7%) | 821(65.9%) | ||||
| Pluri | 742 (36.3%) | 424(34.1%) | ||||
| PTB histroy | 0.529 | |||||
| Yes | 45 (2.2%) | 23 (1.8%) | ||||
| No | 1,998 (97.8%) | 1,222 (98.2%) | ||||
| Conception* | 0.186 | |||||
| Natural | 1,250 (61.2%) | 732 (58.8%) | ||||
| ART | 793 (38.8%) | 513 (41.2%) | ||||
| Chorionicity* | <0.001 | |||||
| Dichorionic | 1,359 (66.5%) | 1,075 (86.3%) | Ref. | |||
| Monochorionic | 684 (33.5%) | 170 (13.7%) | 3.028 | 2.489–3.683 | <0.001 | |
| Height (cm)* | <0.001 | 0.014 | ||||
| <160 | 649 (33.4%) | 323 (26.8%) | 1.171 | 0.985–1.392 | 0.074 | |
| 160–169 | 1,238 (63.7%) | 825 (68.5%) | Ref. | |||
| ≥170 | 56 (2.9%) | 57 (4.7%) | 0.642 | 0.424–0.973 | 0.037 | |
| Pre BMI (kg/m2) | 0.887 | |||||
| <18.5 | 298 (16.3%) | 191 (16.5%) | ||||
| 18.5–23.9 | 1,209 (66.2%) | 761 (65.8%) | ||||
| 24.0–27.9 | 256 (14.0%) | 158 (13.7%) | ||||
| ≥28.0 | 63 (3.5%) | 46 (4.0%) | ||||
| Weight Gain (kg)* | <0.001 | <0.001 | ||||
| <10 | 145 (7.8%) | 44 (3.8%) | 2.285 | 1.563–3.339 | <0.001 | |
| 10–14.9 | 412 (22.3%) | 184 (15.9%) | 1.478 | 1.188–1.839 | <0.001 | |
| 15–19.9 | 675 (36.5%) | 470 (40.6%) | Ref. | |||
| ≥20 | 617 (33.4%) | 460 (39.7%) | 0.899 | 0.753–1.072 | 0.236 | |
| HDP* | <0.001 | <0.001 | ||||
| No | 1,740 (85.2%) | 1,132 (90.9%) | Ref. | |||
| HTN | 4 (0.2%) | 3 (0.2%) | 0.704 | 0.151–3.271 | 0.654 | |
| GH | 60 (2.9%) | 45 (3.6%) | 0.689 | 0.440–1.080 | 0.104 | |
| PE | 239 (11.7%) | 65 (5.2%) | 3.067 | 2.142–4.390 | <0.001 | |
| ICP* | <0.001 | |||||
| Yes | 172 (8.4%) | 34 (2.7%) | 3.122 | 2.121–4.596 | <0.001 | |
| No | 1,871 (91.6%) | 1,211 (97.3%) | 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.