Table 2.

Selected characteristics of participants in the NINFEA study^a.

Characteristics		N=7003 (%)
Maternal age, y
	≤25	5.0
	26-31	33.3
	32-35	35.0
	≥36	26.7
	Missing data	0.1
Maternal origin
	Italian born	95.8
	Non-Italian born	4.2
Maternal residence
	North Italy	71.3
	Central Italy	25.2
	South Italy	3.5
Maternal educational level
	Primary school	5.8
	Secondary/college	33.8
	University/tertiary	58.6
	Missing data	1.8
First pregnancy
	No	32.7
	Yes	63.3
	Missing data	4.0
Stage of pregnancy at recruitment
	Trimester 1	15.3
	Trimester 2	36.0
	Trimester 3	48.5
	Missing data	0.2
Smoking during pregnancy
	No	89.3
	Yes	8.4
	Missing data	2.4
Drinking during pregnancy
	No	64.4
	Yes	33.7
	Missing data	1.9

^aDatabase version 15.03 (March 2015).