Table 1 Socio-demographic data for the study population

Age (mean/SD)**

0.602

Marital status*

0.989

 Married/Cohabiting

133

92.4

150

93.2

 Single

11

5.6

11

6.8

Sick leave at registration*

0.014

 Yes

9

7.0

2

1.3

 No

120

93.0

156

98.7

Socioeconomic group*

0.132

 Higher education

41

33.6

63

40.1

 Lower education

47

38.5

52

33.1

 Unemployed/parental leave

21

17.2

16

10.2

 Student

13

10.7

26

16.6

BMI in the beginning of pregnancy*

0.540

 −24.9

60

45.8

80

50.6

 25–29.9

46

35.1

55

34.8

 30-

25

19.1

23

14.5

Tobacco use*

0.007

 Yes

30

22.6

17

10.7

 No

103

77.4

142

89.3

Parity*

0.085

 0

78

49.1

84

50.3

 1

43

27.0

58

34.7

 2 or more

38

23.9

25

15.0