|
Maternal medical background
|
|
Ca intake before pregnancy mg/day median (inter-quartile range)
|
199 (154–235)
|
321 (295–347)
|
430 (401–460)
|
567 (529–613)
|
899 (755–1253)
|
< 0.001a
|
|
Maternal age, years mean (SD)
|
28.5 (5.1)
|
29.9 (5.1)
|
30.4 (5.0)
|
30.7 (4.9)
|
30.8 (5.1)
|
< 0.001b
|
|
Advanced maternal age, %
|
13.4
|
19.2
|
21.3
|
22.9
|
24.2
|
< 0.001c
|
|
Pre-pregnancy BMI (kg/m2), %
|
|
< 18.5
|
19.1
|
18.4
|
16.2
|
16.7
|
16.1
|
< 0.001c
|
|
18.5 to 25.0
|
71.4
|
72.4
|
75.3
|
75.0
|
76.2
|
|
> 25.0
|
9.5
|
9.2
|
8.6
|
8.4
|
7.7
|
|
Smoking during pregnancy, %
|
5.5
|
3.5
|
3.1
|
2.6
|
2.7
|
< 0.001c
|
|
Sterility treatment, %
|
7.3
|
10.7
|
10.8
|
11.5
|
12.2
|
< 0.001c
|
|
Maternal education, year, %
|
|
< 10
|
5.8
|
3.6
|
2.6
|
2.3
|
2.5
|
< 0.001c
|
|
10 to 12
|
36.7
|
29.9
|
25.8
|
24.3
|
24.8
|
|
13 to 16
|
39.6
|
43.0
|
43.2
|
43.2
|
43.9
|
|
more than 17
|
17.7
|
23.6
|
28.5
|
30.2
|
28.8
|
|
Household income, JPY, %
|
|
<2,000,000
|
8.1
|
5.7
|
4.7
|
4.4
|
4.8
|
< 0.001c
|
|
2,000,000–5,999,999
|
69.5
|
66.4
|
65.6
|
64.1
|
64.1
|
|
6,000,000–9,999,999
|
19.5
|
23.7
|
24.9
|
26.4
|
25.7
|
|
≥10,000,000
|
3.0
|
4.2
|
4.9
|
5.1
|
5.3
|
|
Obstetric outcome
|
|
HDP, %
|
3.1
|
3.4
|
3.5
|
3.2
|
3.1
|
0.719d
|
|
Eo-HDP, %
|
0.5
|
0.7
|
0.5
|
0.5
|
0.6
|
0.739d
|
|
Lo-HDP, %
|
2.3
|
2.4
|
2.6
|
2.4
|
2.2
|
0.655d
|
|
PTB < 37 wks, %
|
4.4
|
3.9
|
4.5
|
4.2
|
4.0
|
0.322d
|
|
LBW < 2500 g, %
|
9.7
|
8.6
|
8.7
|
9.0
|
8.9
|
0.213d
|
