Table 2 Characteristics of twin pregnancy women with and without sPTB in the training set
Characteristics | Control (n = 928) | sPTB (n = 385) | P |
|---|---|---|---|
Age (years), n (%) |  |  | < 0.001 |
 < 35 | 796 (85.8) | 285 (74.0) |  |
 ≥ 35 | 132 (14.2) | 100 (26.0) |  |
Pre-pregnancy BMI (kg/m2), n (%) |  |  | < 0.001 |
 Normal | 769 (82.9) | 266 (69.1) |  |
 Underweight | 77 (8.30) | 59 (15.3) |  |
 Overweight | 76 (8.19) | 44 (11.4) |  |
 Obesity | 6 (0.65) | 16 (4.16) |  |
Nulliparity, n (%) | Â | Â | 0.045 |
 No | 196 (21.1) | 62 (16.1) |  |
 Yes | 732 (78.9) | 323 (83.9) |  |
Chorionicity, n (%) | Â | Â | 0.114 |
 Dichorionic diamniotic | 810 (87.3) | 321 (83.4) |  |
 Monochorionic diamniotic | 116 (12.5) | 63 (16.4) |  |
 Monochorionic monoamniotic | 2 (0.22) | 1 (0.26) |  |
Conception modalities, n (%) | Â | Â | 0.308 |
 Spontaneous conception | 264 (28.4) | 122 (31.7) |  |
 IVF | 653 (70.4) | 256 (66.5) |  |
 Ovulation induction | 11 (1.19) | 7 (1.82) |  |
Pre-pregnancy diabetes, n (%) |  |  | < 0.001 |
 No | 909 (98.0) | 343 (89.1) |  |
 Yes | 19 (2.05) | 42 (10.9) |  |
Gestation diabetes, n (%) | Â | Â | 0.694 |
 No | 684 (73.7) | 279 (72.5) |  |
 Yes | 244 (26.3) | 106 (27.5) |  |
Pre-pregnancy hypertension, n (%) | Â | Â | 0.001 |
 No | 909 (98.0) | 363 (94.3) |  |
 Yes | 19 (2.05) | 22 (5.71) |  |
Hypertensive disorders of pregnancy, n (%) | Â | Â | 0.154 |
 No | 806 (86.9) | 346 (89.9) |  |
 Yes | 122 (13.1) | 39 (10.1) |  |
Scarred uterus, n (%) | Â | Â | 0.216 |
 No | 868 (93.5) | 352 (91.4) |  |
 Yes | 60 (6.47) | 33 (8.57) |  |
Infections, n (%) | Â | Â | 0.144 |
 No | 852 (91.8) | 343 (89.1) |  |
 Yes | 76 (8.19) | 42 (10.9) |  |
Cervical incompetence, n (%) |  |  | < 0.001 |
 No | 900 (97.0) | 338 (87.8) |  |
 Yes | 28 (3.02) | 47 (12.2) |  |
Thyroid abnormalities, n (%) |  |  | 0.894 |
 No | 830 (89.4) | 346 (89.9) |  |
 Yes | 98 (10.6) | 39 (10.1) |  |
Anemia, n (%) | Â | Â | 0.069 |
 Normal | 726 (78.2) | 276 (71.7) |  |
 Mild | 119 (12.8) | 65 (16.9) |  |
 Moderate | 67 (7.22) | 33 (8.57) |  |
 Severe | 16 (1.72) | 11 (2.86) |  |
Hypoproteinemia, n (%) | Â | Â | 0.364 |
 No | 848 (91.4) | 345 (89.6) |  |
 Yes | 80 (8.62) | 40 (10.4) |  |
Thrombocytopenia, n (%) | Â | Â | 0.234 |
 No | 867 (93.4) | 367 (95.3) |  |
 Yes | 61 (6.57) | 18 (4.68) |  |