Table 4. Baseline profiles of the children in the Japan Environment and Children’s Study, 2011–2014.

Variables	Total			With participating fathers
	Number of valid response	n		Number of valid response	n
Number of live births	100,148			51,539
Singleton births, n %		98,259	98.1		50,564	98.1
Gestational age at birth	100,148			51,539
Total, weeks, mean (SD)		100,148	39.2 (1.7)		51,539	39.2 (1.6)
Preterm births (<37 weeks), n %		5,599	5.6		2,644	5.1
Term births (37–41 weeks), n %		94,322	94.2		48,763	94.6
Postterm births (≥42 weeks), n %		227	0.2		132	0.3
Sex	100,137			51,534
Male, n %		51,316	51.2		26,279	51.0
Female, n %		48,821	48.8		25,255	49.0
Type of delivery	99,884			51,413
Vaginal, n %		79,783	79.9		41,212	80.2
Caesarean, n %		20,101	20.1		10,201	19.8
Birth weight, g	100,071			51,509
Total, mean (SD)		100,071	3,008 (434)		51,509	3,015 (425)
Singleton births	98,182			50,534
Total, mean (SD)		98,182	3,023 (420)		50,534	3,030 (410)
Male, mean (SD)		50,312	3,065 (426)		25,779	3,074 (415)
Female, mean (SD)		47,863	2,979 (408)		24,751	2,984 (399)
Low birth weight, <2,500 g, n %		7,981	8.1		3,856	7.6
Birth height, cm	99,785			51,336
Total, mean (SD)		99,785	48.8 (2.4)		51,336	48.9 (2.3)
Singleton births	97,912			50,368
Total, mean (SD)		97,912	48.9 (2.3)		50,368	49.0 (2.2)
Male, mean (SD)		50,166	49.2 (2.3)		25,690	49.3 (2.2)
Female, mean (SD)		47,740	48.6 (2.3)		24,675	48.7 (2.2)
Birth head circumference, cm	99,538			51,222
Total, mean (SD)		99,538	33.2 (1.5)		51,222	33.2 (1.5)
Singleton births	97,692			50,265
Total, mean (SD)		97,692	33.2 (1.5)		50,265	33.2 (1.5)
Male, mean (SD)		50,054	33.4 (1.5)		25,635	33.4 (1.5)
Female, mean (SD)		47,633	33.0 (1.5)		24,627	33.0 (1.4)
Birth chest circumference, cm	99,489			51,198
Total, mean (SD)		99,489	31.7 (1.9)		51,198	31.7 (1.8)
Singleton births	97,653			50,245
Total, mean (SD)		97,653	31.8 (1.8)		50,245	31.8 (1.8)
Male, mean (SD)		50,034	31.9 (1.9)		25,625	31.9 (1.8)
Female, mean (SD)		47,614	31.6 (1.8)		24,617	31.6 (1.8)

SD, standard deviation.