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Table 3 Comparison between preterm and non-preterm neonates in 1980 and 2004

From: Factors associated with birthweight decline in Japan (1980–2004)

variables

units

1980

2004

Preterm (n = 63,821)

non-Preterm (n = 1,505,946)

Preterm (n = 62,935)

non-Preterm (n = 1,047,338)

mean

SD

mean

SD

mean

SD

mean

SD

Birthweight

grams

2396

608

3223

402

2191

590

3063

377

Gestational age

weeks

34.27

2.46

39.47

1.23

34.28

2.73

39.11

1.17

Father age

years of age

30.70

4.78

30.31

4.19

32.49

5.95

31.63

5.59

Mother age

years of age

28.10

4.37

27.60

3.71

30.43

5.00

29.65

4.69

Delivery number

including present birth

1.93

1.01

1.79

0.83

1.82

0.92

1.69

0.81

Multiple gestation

1 = singleton 2 = multiple birth

1.03

0.18

1.01

0.09

1.22

0.41

1.01

0.10

live birth number

 

1.89

0.98

1.78

0.82

1.80

0.91

1.68

0.80

Neonatal gender

1 = male 2 = female

1.43

0.50

1.49

0.50

1.44

0.50

1.49

0.50