Table 1.

Characteristics of study participants in the Lifestyle During Pregnancy Study–Danish National Birth Cohort (LDPS-DNBC) ($n=\mathrm{1,592}$).

Characteristics	$n$ or Mean	Percent or standard deviation
Maternal age at child birth (years)	30.8	4.4
Maternal IQa	100.1	15
Gestational week of blood drawa	8.7	2.5
Child's sex
Female	761	47.8
Male	831	52.2
Parity
0	801	50.3
1	511	32.1
$>1$	280	17.6
Socioeconomic status (SES)b
High	1,131	71.0
Medium	412	25.9
Low	43	2.7
Missing	6	0.4
Maternal alcohol consumption during pregnancy
Never	756	47.5
1–4 glasses per week	655	41.1
$>4$ glasses per week	181	11.4
Maternal smoking during pregnancy
No	1,097	68.9
Yes	495	31.1
Maternal prepregnancy body mass index (BMI)a
$<18.5$	61	3.8
18.5–24.9	1,093	68.7
25.0–29.9	292	18.3
$\ge 30$	116	7.3
Missing	30	1.9

^a8 and 135 observations were missing information about maternal IQ and gestational week of blood draw, respectively.

^bSES was created based on self-reported maternal and paternal education and occupation using three categories (high, medium, and low): higher education (four years beyond high school) or work in management were classified as high, skilled workers and middle-range education as medium, unskilled workers and unemployed as low.