Table 1

Characteristics of pregnant women and their offspring (n=82 877)

Characteristics	n	%
Number of coexist disease
0	54 535	65.8
1	25 341	30.6
≥2	3001	3.6
Mother age at birth
<24	7815	9.4
25–29	22 721	27.4
30–34	29 555	35.7
35–39	18 940	22.9
≥40	3846	4.6
Parity
0	36 302	43.8
1	30 646	37.0
≥2	15 929	19.2
Mother education
Junior high school	3630	4.4
High school	25 917	31.3
Vocational junior or technical college	35 323	42.6
≥University	18 007	21.7
Maternal smoking habits
Non-smoking or exit-smoking before pregnancy	68 145	82.2
Exit-smoking after pregnancy	11 324	13.7
Still-smoking	3408	4.1
Maternal drinking habits
Non-drinker	41 481	50.1
Exit drinking after pregnancy	39 143	47.2
Drinking	2253	2.7
Annual household income (1000 JPY)
<200	4193	5.1
200–399	28 476	34.4
400–599	28 663	34.6
600–799	13 045	15.7
800–999	5233	6.3
1000–1199	1870	2.3
1200–1499	735	0.9
1500–1999	427	0.5
≥2000	235	0.3
Child sex
Boys	42 563	51.4
Girls	40 314	48.6