Table 1 Characteristics of the solvent exposed and unexposed study groups, and the source population

Number of observations

26 415

712

10 561

Births with maternal age <18 years (%)

2.1

1.1

2.6

Maternal alcohol abuse in pregnancy (%)

0.5

0.7

0.3

Maternal tobacco smoking in pregnancy (%)

1.9

1.7

1.3

Maternal malformation (%)

1.2

1.0

1.4

Maternal diabetes mellitus

0.1

0.0

0.1

Mean first antenatal visit in weeks (SD)³

14.2 (7.9)

14.1 (7.6)

13.6 (7.1)

Primiparous births (%)

52.4

48.3

46.8

Stillborn (%)

1.0

1.1

0.8

Mean maternal age in years (SD)³

25.2 (5.1)

24.3 (4.6)

25.1 (5.1)