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["Table S1. Characteristics of the study population in the training and validation cohorts"]
[]
["Feature","Training cohort (n=1405)","Validation cohort (n=601)","χ2/Z","p"]
["Maternal age [n(%)]",null,null,"4.386a",0.036]
["19~34 years","1129 (80.4%)","458 (76.2%)"]
["<19 years or >34 years","276 (19.6%)","143 (23.8%)"]
["Week gestational [M(P25,P75)，weeks]","22 (18,25)","22 (17,25)","-0.049b",0.961]
["Abdominal pain [n(%)]",null,null,"0.430a",0.807]
["No","815 (58.0%)","341 (56.7%)"]
["mild ","479 (34.1%)","214 (35.6%)"]
["frequent","111 (7.9%)","46 (7.7%)"]
["Vaginal bleeding [n(%)]",null,null,"0.665a",0.717]
["No","718 (51.1%)","316 (52.6%)"]
["Less than menstrual flow","581 (41.4%)","237 (39.4%)"]
["More than menstrual flow","106 (7.5%)","48 (8.0%)"]
["Vaginal discharge [n(%)]",null,null,"2.965a",0.085]
["No","1348 (95.9%)","586 (97.5%)"]
["Yes","57 (4.1%)","15 (2.5%)"]
["Cervical length [n(%)]",null,null,"1.015a",0.602]
["≥30mm","788 (56.1%)","328 (54.6%)"]
["≥ 20 and ＜30","274 (19.5%)","129 (21.5%)"]
["＜20mm","343 (24.4%)","144 (24.0%)"]
["History of preterm birth [n(%)]",null,null,"0.879a",0.348]
["No","1377 (98%)","585 (97.3%)"]
["Yes","28 (2.0%)","16 (2.7%)"]
["Second Trimester Miscarriage history [n(%)]",null,null,"0.028a",0.868]
["No","1312 (93.4%)","560 (93.2%)"]
["Yes","93 (6.6%)","41 (6.8%)"]
["Number of intrauterine procedures [n(%)]",null,null,"3.716a",0.156]
["No","763 (54.3%)","300 (49.9%)"]
[1,"352 (25.1%)","172 (28.6%)"]
["≥2","290 (20.6%)","129 (21.5%)"]
["Subchorionic hematoma[n(%)]",null,null,"0.541a",0.763]
["No","1194 (85.0%)","506 (84.2%)"]
["≤10mm","60 (4.3%)","24 (4.0%)"]
["＞10mm","151 (10.7%)","71 (11.8%)"]
["Uterine fibroids [n(%)]",null,null,"3.453a",0.063]
["＜5mm","1324 (94.2%)","553 (92.0%)"]
["≥5mm","81 (5.8%)","48 (8.0%)"]
["Parity[n(%)]",null,null,"3.880a",0.144]
[0,"951 (67.7%)","389 (64.7%)"]
[1,"375 (26.7%)","165 (27.5%)"]
["≥2","79 (5.6%)","47 (7.8%)"]
["WBC [M(P25,P75)，×10^9/L]","10.5 (8.85,12.4)","10.5 (8.8,12.5)","-0.172b",0.863]
["Neutrophil percentage [M(P25,P75)，%]","79 (75,83)","79 (75,83)","-0.502b",0.615]
["CRP [M(P25,P75)，mg/L]","2.9 (1.4,6.1)","2.9 (1.4,6.3)","-1.069b",0.285]
["Pre-pregnancy BMI [n(%)]",null,null,"0.743a",{"v":0.69,"d":"0.690"}]
["18.5~27.9kg/m²","1142 (81.3%)","481 (80.0%)"]
["＜18.5kg/m²","133 (9.5%)","57 (9.5%)"]
["≥28kg/m²","130 (9.3%)","63 (10.5%)"]
["Vaginitis during pregnancy [n(%)]",null,null,"1.375a",0.241]
["No","977 (69.5%)","402 (66.9%)"]
["Yes","428 (30.5%)","199 (33.1%)"]
["Assisted pregnancy [n(%)]",null,null,"0.003a",0.953]
["No","1158 (82.4%)","496 (82.5%)"]
["Yes","247 (17.6%)","105 (17.5%)"]
["Multiple pregnancies [n(%)]",null,null,"0.374a",0.541]
["No","1230 (87.5%)","532 (88.5%)"]
["Yes","175 (12.5%)","69 (11.5%)"]
["Diabetes [n(%)]",null,null,"2.011a",0.156]
["No","1275 (90.7%)","533 (88.7%)"]
["Yes","130 (9.3%)","68 (11.3%)"]
["Hypertension [n(%)]",null,null,"3.058a",{"v":0.08,"d":"0.080"}]
["No","1382 (98.4%)","584 (97.2%)"]
["Yes","23 (1.6%)","17 (2.8%)"]
["Anemia [n(%)]",null,null,"0.083a",0.773]
["No","1379 (98.1%)","591 (98.3%)"]
["Yes","26 (1.9%)","10 (1.7%)"]
["Thrombophilia [n(%)]",null,null,"0.045a",0.831]
["No","1338 (95.2%)","571 (95.0%)"]
["Yes","67 (4.8%)","30 (5.0%)"]
["Thyroid disease [n(%)]",null,null,"1.191a",0.275]
["No","1284 (91.4%)","558 (92.8%)"]
["Yes","121 (8.6%)","43 (7.2%)"]
["Scar uterus[n(%)]",null,null,"2.287a",{"v":0.13,"d":"0.130"}]
["No","1234 (87.8%)","513 (85.4%)"]
["Yes","171 (12.2%)","88 (14.6%)"]
["Placental abnormalities [n(%)]",null,null,"2.264a",0.322]
["No","1187 (84.5%)","514 (85.5%)"]
["Abnormal development","174 (12.4%)","63 (10.5%)"]
["Placenta previa","44 (3.1%)","24 (4.0%)"]
["Abnormal amniotic fluid volume [n(%)]",null,null,"0.022a",0.881]
["No","1354 (96.4%)","580 (96.5%)"]
["Yes","51 (3.6%)","21 (3.5%)"]
["Uterine abnormalities [n(%)]",null,null,"0.767a",0.381]
["No","1403 (99.9%)","599 (99.7%)"]
["Yes","2 (0.1%)","2 (0.3%)"]
["Neoplasms of cervix [n(%)]",null,null,"0.606a",0.436]
["No","1348 (95.9%)","581 (96.7%)"]
["Yes","57 (4.1%)","20 (3.3%)"]
["After cervical surgery [n(%)]",null,null,"0.359a",0.549]
["No","1350 (96.1%)","55 (3.9%)"]
["Yes","574 (95.5%)","27 (4.5%)"]
[]
["a: Pearson's chi-squared test, b: U Mann–Whitney test\nContinuous variables were expressed as median (interquartile range); n (percentage) for categorical variables\nAbbreviations: WBC White blood cell count, CRP C-reactive protein, BMI Body Mass Index"]