Variable Univariate analysis Univariate analysis Univariate analysis Multivariate analysis Multivariate analysis Multivariate analysis
OR 95% CI P value aOR 95% CI P value
History of placental abruption 3.9 1.5 – 10.7 0.007 3.5 1.3 – 9.6 0.013
ART pregnancy 2.0 1.3 – 3.0 0.002 1.7 1.1 – 2.7 0.021
Parity
0 Ref Ref
1 0.9 0.7 – 1.1 0.303 0.9 0.7 – 1.1 0.246
2 1.1 0.9 – 1.5 0.315 1.1 0.8 – 1.4 0.684
3 1.0 0.6 – 1.7 0.956 0.9 0.5 – 1.5 0.620
≥ 4 1.2 0.5 – 3.0 0.648 1.0 0.4 – 2.4 0.969
Maternal age, years
< 20 2.9 1.2 – 6.6 0.013 2.8 1.2 – 6.5 0.016
20 – 24 Ref Ref
25 – 29 1.0 0.7 – 1.6 0.834 1.1 0.7 – 1.6 0.810
30 – 34 1.4 1.0 – 2.2 0.078 1.5 1.0 – 2.2 0.070
≧35 1.7 1.1 – 2.6 0.012 1.6 1.1 – 2.5 0.024
Smoking during pregnancy 1.7 1.2 – 2.4 0.004 1.7 1.2 – 2.5 0.003
BMI
< 18.5 kg/m2 1.1 0.9 – 1.5 0.346 1.2 0.9 – 1.5 0.250
18.5 – 24.9 kg/m2 Ref Ref
≥ 25 kg/m2 1.3 1.0 – 1.8 0.062 1.1 0.8 – 1.5 0.386
Chronic hypertension 4.3 2.8 – 6.7 < 0.001 4.0 2.5 – 6.2 < 0.001
Uterine myoma 1.0 0.7 – 1.5 0.894 0.9 0.6 – 1.3 0.578