Table 2 Heterogeneity test and meta-analysis results of NEC risk factors in premature infants

Septicemia

25

43.43

45

0.009

Fixed effect

3.91 (3.37, 4.55)

< 0.001

Blood transfusion

13

23.68

49

0.02

Fixed effect

2.41 (1.97, 2.95)

< 0.001

Neonatal asphyxia

14

23.58

45

0.04

Fixed effect

2.46 (2.07, 2.93)

< 0.001

Pneumonia

6

1.34

0

0.93

Fixed effect

6.17 (3.98, 9.57)

< 0.001

Infection occurs

2

1.43

30

0.23

Fixed effect

5.99 (2.57, 13.93)

< 0.001

Oral probiotics

17

96.90

83

< 0.001

Random effect

0.36 (0.25, 0.53)

< 0.001

Breastfeeding

13

302.01

96

< 0.001

Random effect

0.31 (0.16, 0.62)

< 0.001

Congenital heart disease

3

2.01

1

0.37

Fixed effect

4.80 (3.00, 7.68)

< 0.001

Intrahepatic cholestasis of pregnancy

4

2.17

0

0.54

Fixed effect

2.71 (1.92, 3.82)

< 0.001

Mechanical ventilation

4

0.68

0

0.88

Fixed effect

1.44 (1.22, 1.71)

< 0.001

Gestational diabetes

2

0.06

0

0.80

Fixed effect

3.08 (1.73, 5.48)

0.0001

Respiratory distress syndrome

4

1.24

0

0.74

Fixed effect

3.28 (2.23, 4.85)

< 0.001

Prenatal application of glucocorticoids

5

6.19

35

0.19

Fixed effect

0.38 (0.24, 0.60)

< 0.001

Intravenous Immunoglobulin

2

5.46

82

0.02

Random effect

0.70 (0.10, 5.20)

0.73

Hypoalbuminemia

2

0.43

0

0.51

Fixed effect

2.80 (1.78, 4.41)

< 0.001

Patent ductus arteriosus

3

0.28

0

0.87

Fixed effect

3.10 (1.93, 4.98)

< 0.001

respiratory failure

2

3.50

71

0.06

Random effect

7.51 (1.60, 35.10)

0.01

Severe anemia

4

2.02

0

0.57

Fixed effect

2.86 (2.06, 3.99)

< 0.001

History of antibiotic use

2

4.53

78

0.03

Random effect

2.12 (1.18, 3.81)

0.01

Meconium-stained amniotic fluid

2

0.05

0

0.82

Fixed effect

3.14 (1.64, 6.01)

< 0.001