Table 2.
Demographic and Clinical Characteristics of Study Population
| Characteristic | Preterm (n=96) | Term (n=426) | p value |
|---|---|---|---|
| Maternal age, yearsa | 30.6±4.2 | 32.3±4.1 | <0.001 |
| 20–24 | 8 (8.3%) | 8 (1.9%) | <0.01 |
| 25–29 | 29 (30.2%) | 102 (23.9%) | |
| 30–34 | 44 (45.8%) | 186 (43.7%) | |
| 35–39 | 13 (13.5%) | 113 (26.5%) | |
| ≥40 | 2 (2.1%) | 17 (4.0%) | |
| Prepregnancy body weight (kg)a | 54.5±9.6 | 54.7±8.2 | NS |
| Maternal body weight at delivery (kg)a | 64.1±10.8 | 67.9±8.6 | <0.01 |
| Weight gain per week (kg)a | 0.30±0.1 | 0.34±0.1 | NS |
| Maternal height (cm)a | 160.5±4.5 | 161.5±4.8 | NS |
| Prepregnancy BMIa,b | 21.1±3.7 | 20.9±3.1 | NS |
| <18.5 | 10 (22.7%) | 76 (20.1%) | |
| 18.5–22.9 | 24 (54.5%) | 231 (60.9%) | |
| 23.0–24.9 | 5 (11.4%) | 34 (9.0%) | |
| ≥25 | 5 (11.4%) | 38 (10.0%) | |
| Maternal BMI at deliverya,c | 24.9±4.0 | 26.0±3.0 | <0.01 |
| <18.5 | 0 (0.0%) | 0 (0.0%) | <0.001 |
| 18.5–22.9 | 33 (34.4%) | 58 (13.8%) | |
| 23.0–24.9 | 23 (24.0%) | 111 (26.4%) | |
| ≥25 | 40 (41.7%) | 251 (59.8%) | |
| BMI increase per weeka | 0.12±0.05 | 0.13±0.04 | NS |
| Gestational age at delivery (weeks)a | 34.5±2.5 | 39.6±1.1 | <0.001 |
| Multiparityd | 57 (60.0%) | 224 (52.7%) | NS |
| Prior preterm birthe | 6 (11.3%) | 10 (2.9%) | <0.05 |
| Maternal education ≤12 yearsf | 37 (41.6%) | 82 (19.9%) | <0.001 |
| Paternal education ≤12 yearsg | 7 (23.3%) | 52 (14.5%) | NS |
| With maternal occupationh | 9 (28.1%) | 130 (36.5%) | NS |
| Income <USD 2,500i | 15 (48.4%) | 169 (46.9%) | NS |
| Smokingj | 4 (12.5%) | 37 (10.3%) | NS |
| Passive smokingk | 16 (50.0%) | 139 (38.7%) | NS |
| Cervical length (cm)a | 2.83±1.35 | 3.83±0.66 | <0.001 |
| Short cervix | 32 (33.3%) | 4 (0.9%) | <0.001 |
| Positive fetal fibronectin | 20 (20.8%) | 1 (0.2%) | <0.001 |
Values are given as mean±standard deviation.
Denominators are 44 for the preterm group and 379 for the term group.
A denominator is 420 for term group.
Denominators are 95 for the preterm group and 425 for the term group.
Denominators are 53 for the preterm group and 347 for the term group.
Denominators are 89 for the preterm group and 413 for the term group.
Denominators are 30 for the preterm group and 359 for the term group.
Denominators are 32 for the preterm group and 356 for the term group.
Denominators are 31 for the preterm group and 360 for the term group.
Denominators are 32 for the preterm group and 358 for the term group.
Denominators are 32 for the preterm group and 359 for the term group.
BMI, body mass index; NS, not significant; USD, US dollars.