Table 1 Summary of the demographic characteristics of participants

Infant sex [case (percentage, %)]

1.923¹

0.382

 males

33(47.1)

34(55.7)

33(58.9)

 female

37(52.9)

27(44.3)

23(41.1)

Gestational age (weeks, ‾X ± s)

26.38 ± 1.25

26.37 ± 1.21

26.13 ± 1.43

0.726²

0.485

birth weight(g, ‾X ± s)

873.29 ± 195.05

912.46 ± 167.38

833.11 ± 217.42

2.450²

0.089

Mode of delivery [ case (percentage, %)]

1.565¹

0.457

 Cesarean section

25(35.7)

27(44.3)

19(33.9)

 vaginal delivery

45(64.3)

34(55.7)

37(66.1)

SNAPPEII

22.94 ± 13.14

19.25 ± 11.48

24.16 ± 12.75

2.509²

0.084

Hospitalization days (days)

75.8 ± 19.67

73.59 ± 16.14

80.34 ± 25.11

1.644²

0.196

Maternal education level [case (percentage, %)]

4.681¹

0.322

 Primary and Junior High

15(21.4)

20(32.8)

11(19.6)

 High school, technical secondary school

24(43.3)

13(21.3)

18(32.1)

 Bachelor degree, college degree and above

31(44.3)

28(45.9)

27(48.2)

Father ‘s education level [case (percentage, %)]

8.609¹

0.072

 Primary and junior high

19(27.1)

24(39.3)

9(16.1)

 High school, technical secondary school

25(35.7)

15(24.6)

20(35.7)

 Bachelor degree, college degree and above

26(37.1)

22(36.1)

27(48.2)

Corrected head circumference at gestational age of 37 weeks (cm, ‾X ± s)

31.86 ± 1.55

31.33 ± 1.48

31.89 ± 1.69

2.476²

0.087

Corrected length at a gestational age of 37 weeks(cm, ‾X ± s)

45.94 ± 1.65

46.65 ± 1.39

47.13 ± 1.03

11.542²

<0.001

Corrected weight at a gestational age of 37 weeks(g, ‾X ± s)

2534.79 ± 132.21

2694.26 ± 254.44

2710.09 ± 218.66

14.652²

<0.001

Corrected head circumference Z-score at a gestational age of 37 weeks.

-0.96 ± 1.2

-1.36 ± 1.14

-0.93 ± 1.3

2.476²

0.087

Corrected length Z-score at a gestational age of 37 weeks

-1.29 ± 0.66

-0.93 ± 0.59

-0.72 ± 0.54

14.175²

<0.001

Corrected weight Z-score at a gestational age of 37 weeks

-1.05 ± 0.36

-0.62 ± 0.69

-0.58 ± 0.59

14.652²

<0.001