Table 2 Univariate analysis of socio-economic status and preterm birth

Education

lower education

31

18.0

39

22.7

1

higher education

141

82.0

133

77.3

0.72

0.41-1.27

0.260

Family income(dollars, per month)

 ≥1000

78

45.3

70

40.7

1

 <1000

94

54.7

102

59.3

1.31

0.79-2.18

0.303

Family living space (m², per person)

 ≥20

123

71.5

106

61.6

1

 <20

49

28.5

66

38.4

1.90

1.09-3.30

0.024