Table 1.
Baseline characteristics of patients in the training and validation cohorts.
| Variable | Training Cohort (n = 392) | Validation Cohort (n = 176) | P value |
|---|---|---|---|
| Patient characteristics | |||
| Maternal age, years, mean ± SD | 33.97 ± 8.65 | 34.57 ± 8.49 | 0.441a |
| BMI before pregnancy, kg/m2, mean ± SD | 25.18 ± 5.81 | 25.06 ± 5.96 | 0.825a |
| Cervical length, mm, mean ± SD | 16.16 ± 4.88 | 15.67 ± 4.55 | 0.258a |
| Parity, n (%) | 0.176b | ||
| 0 | 265 (67.6) | 108 (61.4) | |
| ≥1 | 127 (32.4) | 68 (38.6) | |
| Uterine curettage, n (%) | 0.948b | ||
| Yes | 40 (10.2) | 19 (10.8) | |
| No | 352 (89.8) | 157 (89.2) | |
| Alcohol drinking history, n (%) | 0.747b | ||
| Yes | 43 (11.0) | 17 (9.7) | |
| No | 349 (89.0) | 159 (90.3) | |
| Smoking history, n (%) | 0.987b | ||
| Yes | 5 (1.3) | 3 (1.7) | |
| No | 387 (98.7) | 173 (98.3) | |
| Family history of diabetes mellitus, n (%) | 0.943b | ||
| Yes | 38 (9.7) | 16 (9.1) | |
| No | 354 (90.3) | 160 (90.9) | |
| History of hypertension, n (%) | 0.845b | ||
| Yes | 14 (3.6) | 5 (2.8) | |
| No | 378 (96.4) | 171 (97.2) | |
| GDM, n (%) | 0.918b | ||
| Yes | 44 (11.2) | 21 (11.9) | |
| No | 348 (88.8) | 155 (88.1) | |
| HDP, n (%) | 0.983b | ||
| Yes | 33 (8.4) | 14 (8.0) | |
| No | 359 (91.6) | 162 (92.0) | |
| Anemia, n (%) | 1.000b | ||
| Yes | 52 (13.3) | 24 (13.6) | |
| No | 340 (86.7) | 152 (86.4) | |
| C-reactive protein, mg/L, mean ± SD | 7.81 ± 4.69 | 8.02 ± 4.95 | 0.631a |
| Urinary tract infection, n (%) | 0.964b | ||
| Yes | 31 (7.9) | 13 (7.4) | |
| No | 361 (92.1) | 163 (92.6) | |
| Reproductive tract infection, n (%) | 0.917b | ||
| Yes | 55 (14.0) | 26 (14.8) | |
| No | 337 (86.0) | 150 (85.2) | |
| Inter-pregnancy interval, months, mean ± SD | 39.34 ± 21.27 | 40.69 ± 24.89 | 0.507a |
| Household yearly income (yuan), n (%) | 0.958b | ||
| <50,000 | 203 (51.8) | 90 (51.1) | |
| ≥50,000 | 189 (48.2) | 86 (48.9) | |
| Emergency cerclage, n (%) | 0.207b | ||
| Yes | 12 (3.1) | 10 (5.7) | |
| No | 380 (96.9) | 166 (94.3) | |
| Assisted reproductive technologies, n (%) | 1.000b | ||
| Yes | 22 (5.6) | 10 (5.7) | |
| No | 370 (94.4) | 166 (94.3) | |
| Antibiotics use, n (%) | 0.974b | ||
| Yes | 87 (22.2) | 40 (22.7) | |
| No | 305 (77.8) | 136 (77.3) | |
| Strain in the cervix | |||
| AI, mean ± SD | 0.27 ± 0.09 | 0.27 ± 0.10 | 0.844a |
| PI, mean ± SD | 0.31 ± 0.12 | 0.31 ± 0.12 | 0.994a |
| AE, mean ± SD | 0.41 ± 0.11 | 0.42 ± 0.12 | 0.197a |
| PE, mean ± SD | 0.43 ± 0.11 | 0.45 ± 0.11 | 0.141a |
a
, for independent sample t-test.
b
, for chi-square test; SD, standard deviation; BMI, body mass index; GDM, gestational diabetes mellitus; HDP, hypertensive disorders of pregnancy; AI, anterior lip of internal os; AE, anterior lip of external os; PI, posterior lip of internal os; PE, posterior lip of external os.