Table 4 Univariate analysis of maternal nutritional status and preterm birth

Balanced diet

 no

18

10.5

34

19.8

1

 yes

154

89.5

138

80.2

0.43

0.22-0.84

0.014

Supplement folic acid during pregnancy

 <3 months

51

29.7

65

37.8

1

 ≥3 months

121

70.3

107

62.2

0.64

0.39-1.06

0.083

Pre-pregnancy BMI (kg/m²)

20.8 ± 2.5

21.4 ± 2.9

 <18.5

30

17.4

16

9.3

0.55

0.28-1.08

0.083

 18.5-23.9

122

70.9

117

68.0

1

 ≥24

20

11.6

39

22.7

2.15

1.14-4.06

0.018

Gestational weight gain (kg)

17.0 ± 4.6

13.3 ± 5.0

 normal growth (15.2 ± 1.1)

60

34.9

55

32.0

1

 low growth (10.6 ± 2.2)

31

18.0

86

50.0

3.50

1.84-6.66

<0.001

 high growth (21.4 ± 3.5)

81

47.1

31

18.0

0.42

0.23-0.76

0.004