Table 1.

Maternal and children demographic characteristics

	N	% or mean (SD)
Mothers
Active smoking during pregnacny
no	159	84.13
<=5 cigarettes/day	16	8.47
>5 cigarettes/day	14	7.41
Parity
primiparous	110	56.21
multiparous	82	43.79
Cohort
Asturias	33	17.19
Gipuzkoa	64	33.33
Sabadell	70	36.46
Valencia	25	13.02
Education
< secondary school	34	17.71
secondary school	89	46.35
university degree	69	35.94
Age (y)	192	31.83 (3.94)
Body mass index (BMI)	192	23.39 (4.07)
Children
Sex
male	97	49.48
female	95	50.52
Birth weight (g)	191	3301 (411.03)
Gestational age (weeks)	189	39.82 (1.34)