Preterm delivery | Non preterm delivery | p value | |||
---|---|---|---|---|---|
(n = 2343) | (n = 75,324) | ||||
Age, n (%) | < 0.001 | ||||
< 30 years old | 867 | (37.0) | 29,388 | (39.0) | |
30–34 years old | 796 | (34.0) | 26,841 | (35.6) | |
≥ 35 years old | 680 | (29.0) | 19,092 | (25.4) | |
BMI(kg/m2) group, n (%) | < 0.001 | ||||
Leptosome (< 18.5) | 488 | (20.8) | 12,272 | (16.3) | |
Healthy weight(18.5 to < 25) | 1614 | (68.9) | 56,093 | (74.5) | |
Obese (≥ 25) | 240 | (10.3) | 6924 | (9.2) | |
Smoking history, n (%) | 0.083 | ||||
Yes | 999 | (43.1) | 30,862 | (41.3) | |
No | 1321 | (56.9) | 43,931 | (58.7) | |
Nulliparity, n (%) | 0.022 | ||||
Yes | 1015 | (43.6) | 30,927 | (41.2) | |
No | 1314 | (56.4) | 44,135 | (58.8) | |
Educational background (years), n (%) | 0.028 | ||||
< 10 | 132 | (5.9) | 3410 | (4.6) | |
10–12 | 748 | (33.4) | 24,652 | (33.2) | |
13–15 | 883 | (39.4) | 29,886 | (40.2) | |
≥ 16 | 476 | (21.3) | 16,417 | (22.1) | |
Household income (million Japanese Yen/year), n (%) | 0.032 | ||||
< 2 | 139 | (6.6) | 3769 | (5.4) | |
2 to < 4 | 706 | (33.7) | 24,147 | (34.8) | |
4 to < 6 | 728 | (34.7) | 22,976 | (33.1) | |
6 to < 8 | 303 | (14.5) | 11,068 | (15.9) | |
8 to < 10 | 125 | (6.0) | 4577 | (6.6) | |
≥ 10 | 95 | (4.4) | 2947 | (4.2) | |
Working > 42 h/week, n (%) | 0.691 | ||||
Yes | 481 | (20.5) | 15,211 | (20.2) | |
No | 1862 | (79.5) | 60,113 | (79.8) | |
Part-timer, n (%) | 0.863 | ||||
Yes | 371 | (15.8) | 12,027 | (16.0) | |
No | 1972 | (84.2) | 63,297 | (84.0) |