Table 1 Characteristics of the women with twin pregnancies in the training and validation sets
Characteristics | Training set (n = 1313) | Validation set (n = 564) | P value |
|---|---|---|---|
Age (years), n (%) | Â | Â | 0.857 |
 < 35 | 1081 (82.3) | 467 (82.8) |  |
 ≥ 35 | 232 (17.7) | 97 (17.2) |  |
Pre-pregnancy BMI (kg/m2), n (%) | Â | Â | 0.575 |
 Normal | 1035 (78.8) | 443 (78.5) |  |
 Underweight | 136 (10.4) | 63 (11.2) |  |
 Overweight | 120 (9.14) | 53 (9.40) |  |
 Obesity | 22 (1.68) | 5 (0.89) |  |
Nulliparity, n (%) | Â | Â | 0.277 |
 No | 258 (19.6) | 98 (17.4) |  |
 Yes | 1055 (80.4) | 466 (82.6) |  |
Chorionicity, n (%) | Â | Â | 0.460 |
 Dichorionic diamniotic | 1131 (86.1) | 496 (87.9) |  |
 Monochorionic diamniotic | 179 (13.6) | 68 (12.1) |  |
 Monochorionic monoamniotic | 3 (0.23) | 0 (0.00) |  |
Conception modalities, n (%) | Â | Â | 0.106 |
 Spontaneous conception | 386 (29.4) | 142 (25.2) |  |
 IVF | 909 (69.2) | 417 (73.9) |  |
 Ovulation induction | 18 (1.37) | 5 (0.89) |  |
Pre-pregnancy diabetes, n (%) | Â | Â | 0.935 |
 No | 1252 (95.4) | 539 (95.6) |  |
 Yes | 61 (4.65) | 25 (4.43) |  |
Gestation diabetes, n (%) | Â | Â | 0.310 |
 No | 963 (73.3) | 427 (75.7) |  |
 Yes | 350 (26.7) | 137 (24.3) |  |
Pre-pregnancy hypertension, n (%) | Â | Â | 0.893 |
 No | 1272 (96.9) | 545 (96.6) |  |
 Yes | 41 (3.12) | 19 (3.37) |  |
Hypertensive disorders of pregnancy, n (%) | Â | Â | 0.739 |
 No | 1152 (87.7) | 491 (87.1) |  |
 Yes | 161 (12.3) | 73 (12.9) |  |
Scarred uterus, n (%) | Â | Â | 0.554 |
 No | 1220 (92.9) | 529 (93.8) |  |
 Yes | 93 (7.08) | 35 (6.21) |  |
Infections, n (%) | Â | Â | 0.620 |
 No | 1195 (91.0) | 518 (91.8) |  |
 Yes | 118 (8.99) | 46 (8.16) |  |
Cervical incompetence, n (%) |  |  | 0.110 |
 No | 1238 (94.3) | 520 (92.2) |  |
 Yes | 75 (5.71) | 44 (7.80) |  |
Thyroid abnormalities, n (%) |  |  | 0.869 |
 No | 1176 (89.6) | 503 (89.2) |  |
 Yes | 137 (10.4) | 61 (10.8) |  |
Anemia, n (%) | Â | Â | 0.457 |
 Normal | 1002 (76.3) | 447 (79.3) |  |
 Mild | 184 (14.0) | 64 (11.3) |  |
 Moderate | 100 (7.62) | 42 (7.45) |  |
 Severe | 27 (2.06) | 11 (1.95) |  |
Hypoproteinemia, n (%) | Â | Â | 0.727 |
 No | 1193 (90.9) | 516 (91.5) |  |
 Yes | 120 (9.14) | 48 (8.51) |  |
Thrombocytopenia, n (%) | Â | Â | 0.112 |
 No | 1234 (94.0) | 541 (95.9) |  |
 Yes | 79 (6.02) | 23 (4.08) |  |