Variable
Placental abruption (+) N=416 Placental abruption (-) N=93,994
P value
Maternal age (years), mean (SD) 32.0 (5.2) 31.2 (5.0) 0.003a
Maternal age category, %
≦19 years 1.7 0.8 0.001b
20 – 24 years 6.5 8.9
25 – 29 years 20.9 27.5
30 – 34 years 37.3 35.5
≧35 years 33.7 27.3
Parity, %
0 40.9 40.2 0.458b
1 35.5 39.1
2 19.0 16.3
3 3.6 3.5
≥ 4 1.2 1.0
History of placental abruption, % 1.0 0.2 0.021c
ART pregnancy, % 5.5 2.9 0.002b
Smoking during pregnancy, % 7.9 4.9 0.004b
Chronic hypertension, % 5.3 1.3 < 0.001b
Uterine myoma, % 6.3 6.1 0.894b
BMI, %
< 18.5 kg/m2 17.3 16.1 0.144b
18.5 – 24.9 kg/m2 69.3 73.1
≥ 25 kg/m2 13.4 10.8
Obstetric outcomes
Cesarean section, % 62.2 18.6 < 0.001b
UmA pH, mean (SD) 7.21 (0.18) 7.32 (0.12) < 0.001a
UmA pH < 7.20, % 30.7 6.2 < 0.001b
UmA pH < 7.10, % 16.1 1.1 < 0.001b
UmA pH < 7.00, % 10.9 0.2 < 0.001b
Maternal transfusion, % 1.7 0.5 0.004c
Maternal transfusion, % 1.7 0.5 0.004c