Table 1 Quantitative synthesis of eligible positive associations for specific risk/protective factor and CHD

 Family genetic history

5

7751

0.42

3.35 (2.70,4.14)

(2.37,4.73)

0.00

0.24

1.02E-28

1.02E-28

I

 Abortion number

4

2413

0.45

1.28 (1.18,1.40)

(1.06,1.56)

55.24

0.34

1.89E-08

1.91E-08

II

 Maternal parity

14

38,027

0.88

1.22 (1.09,1.36)

(0.83,1.78)

82.65

0.94

3.80E-45

4.22E-04

III

 Singleton IVF/ICSI

5

2159

0.11

1.56 (1.21,2.00)

(0.79,3.08)

35.18

0.66

3.23E-05

5.89E-04

III

 ICSI/IVF pregnancies

8

1047

0.61

1.45 (1.21,1.73)

(0.94,2.23)

43.62

0.57

5.78E-08

4.69E-05

III

 History of spontaneous abortion

9

5377

0.54

1.21 (1.12,1.31)

(1.10,1.34)

11.15

0.64

2.57E-06

2.57E-06

III

 History of abortion

13

7957

0.13

1.22 (1.11,1.34)

(1.00,1.48)

45.77

0.03

3.75E-07

2.49E-05

III

 Gravidity number

7

4381

0.09

1.15 (1.08,1.22)

(0.99,1.33)

41.68

0.47

2.37E-08

7.12E-06

III

 Maternal or fetal abnormalities detected

3

364

0.55

2.37 (1.25,4.49)

(0.02,296.12)

18.79

0.10

3.86E-03

7.88E-03

IV

 Intermarriage

3

467

0.36

2.88 (1.88,4.39)

(0.18,44.83)

0.00

0.53

1.03E-06

1.03E-06

IV

 ICSI vs IVF (in fresh transplantation cycle)

3

72

0.08

2.07 (1.28,3.36)

(0.09,47.47)

0.00

1.00

3.05E-03

3.05E-03

IV

 History of induced abortion

6

1566

0.03

1.68 (1.10,2.55)

(0.44,6.41)

65.48

1.00

1.06E-03

1.64E-02

IV

 Gravidity

10

5464

0.62

1.18 (1.03,1.36)

(0.77,1.81)

62.10

1.00

1.11E-05

2.03E-02

IV

 MC twins without TTTS

5

134

0.77

5.44 (3.66,8.08)

(2.86,10.34)

0.00

0.94

5.57E-17

5.57E-17

IV

 MC twins with TTTS

6

146

0.04

12.50 (8.66,18.04)

(7.43,21.03)

0.00

0.68

2.06E-41

2.06E-41

IV

 MC twins

6

141

0.03

5.88 (4.18,8.28)

(3.62,9.55)

0.00

0.33

3.62E-24

3.62E-24

IV

 MC twins with TTTS vs. MC twins without TTTS

4

123

0.67

2.40 (1.64,3.51)

(1.04,5.53)

0.00

0.74

6.62E-06

6.62E-06

IV

 Maternal severe obesity

5

1497

0.10

1.38 (1.30,1.47)

(1.26,1.53)

0.00

0.25

1.99E-26

1.99E-26

I

 Maternal moderate obesity

5

3835

0.16

1.15 (1.10,1.20)

(1.05,1.27)

33.84

0.24

1.37E-12

4.40E-10

I

 Maternal obesity

20

58,926

0.01

1.33 (1.22,1.46)

(1.02,1.75)

61.64

0.06

5.28E-42

6.93E-10

II

 Paternal age (≥40 years)

11

7456

0.30

1.71 (1.31,2.23)

(0.68,4.29)

94.33

0.00

1.46E-23

9.22E-05

III

 Paternal age (35–39 years)

5

11,219

0.15

1.14 (1.06,1.22)

(0.98,1.32)

16.64

0.94

8.50E-06

1.72E-04

III

 Advanced maternal age (≥35 years)

9

19,212

0.26

1.15 (1.07,1.24)

(0.98,1.36)

22.02

0.01

1.37E-06

2.66E-04

III

 Maternal overweight

19

52,606

0.16

1.06 (1.01,1.12)

(0.93,1.21)

58.58

0.05

1.21E-04

2.20E-02

IV

 Exposure to noise during pregnancy

5

1218

0.03

2.80 (2.09,3.76)

(1.46,5.39)

31.76

0.10

3.28E-14

6.68E-12

II

 Exposure to harmful chemicals during pregnancy

13

3300

0.76

3.35 (2.19,5.13)

(0.88,12.81)

63.80

0.01

2.34E-28

2.82E-08

II

 Exposure of decoration materials during pregnancy

3

3090

0.46

4.21 (2.38,7.47)

(0.03,265.47)

74.50

0.55

6.37E-49

9.68E-07

II

 Maternal educational attainment

30

27,642

0.29

1.13 (1.05,1.21)

(0.90,1.42)

57.14

0.39

4.95E-33

6.01E-04

III

 Paternal smoking

10

8898

0.46

1.42 (1.17,1.73)

(0.72,2.82)

84.85

1.00

8.41E-17

4.07E-04

III

 Paternal active smoking

13

2099

0.44

1.43 (1.19,1.72)

(0.85,2.42)

52.99

1.00

6.87E-12

1.18E-04

III

 Maternal passive smoking

44

15,143

0.00

2.00 (1.65,2.43)

(0.61,6.55)

89.51

0.03

9.58E-55

2.09E-12

III

 Maternal active smoking

85

123,755

0.00

1.30 (1.17,1.44)

(0.57,2.97)

88.20

0.18

3.39E-18

1.11E-06

III

 Paternal occupational exposure to adverse substances

3

919

0.95

1.70 (1.19,2.43)

(0.17,17.30)

0.00

0.57

3.81E-03

3.81E-03

IV

 Family income

5

8150

0.72

1.05 (1.01,1.10)

(0.98,1.13)

0.00

0.37

2.06E-02

2.06E-02

IV

 Solvents exposure

6

2526

0.53

1.32 (1.06,1.63)

(0.97,1.78)

0.00

1.00

1.15E-02

1.15E-02

IV

 Paternal heavy smoking (≥20cigarrette/day)

5

1813

0.03

1.85 (1.01,3.40)

(0.19,18.04)

85.41

0.00

1.22E-02

4.79E-02

IV

 Paternal light smoking (10–19 cigarette/day)

4

1580

0.79

1.41 (1.13,1.76)

(0.64,3.11)

43.08

0.01

4.70E-05

2.48E-03

IV

 High intake of caffeinated products

4

320

0.29

1.32 (1.09,1.60)

(0.86,2.02)

0.00

0.75

5.12E-03

5.12E-03

IV

 Lithium exposure (in the first trimester compared with patients with bipolar disorderd)

3

59

0.39

1.96 (1.13,3.39)

(0.06,69.51)

0.00

1.00

1.69E-02

1.69E-02

IV

 Lithium exposure (in the first trimester compared with general population)

4

15,293

0.41

4.90 (1.72,13.96)

(0.07,322.10)

69.14

0.08

2.70E-07

2.95E-03

IV

 Lithium exposure (in the first trimester compared with unexposed women)

3

15,314

0.28

4.56 (1.59,13.12)

(0.00,627,861.00)

71.78

0.06

1.41E-06

4.89E-03

IV

 SNRIs

4

24,743

0.79

1.67 (1.40,1.98)

(1.09,2.55)

24.27

0.60

9.48E-10

6.07E-09

I

 SSRIs

16

43,170

0.78

1.26 (1.19,1.33)

(1.19,1.34)

32.77

0.37

1.72E-16

1.73E-16

I

 Folic acid supplementation

20

18,276

0.00

0.61 (0.51,0.73)

(0.30,1.22)

79.76

0.00

2.35E-21

2.14E-08

II

 Any antidepressant (in the first trimester)

20

61,539

0.50

1.28 (1.17,1.41)

(0.98,1.69)

48.75

0.46

2.19E-22

2.07E-07

II

 Fluoxetine

14

74,523

0.33

1.30 (1.13,1.50)

(0.98,1.72)

28.25

0.19

3.90E-06

2.40E-04

III

 SSRIs (in the first trimester)

19

74,191

0.63

1.26 (1.13,1.42)

(0.86,1.87)

56.06

0.16

4.29E-15

8.23E-05

III

 Oral hormone pregnancy tests

7

1003

0.76

1.90 (1.26,2.86)

(0.93,3.86)

0.00

0.95

5.75E-04

2.11E-03

IV

 Sertraline

13

74,598

0.26

1.44 (1.10,1.91)

(0.59,3.53)

63.82

0.02

4.33E-06

9.22E-03

IV

 Nitrate (each additional daily 0.5 mg)

3

826

0.56

1.02 (1.00,1.04)

(0.89,1.17)

0.00

0.15

4.26E-02

4.26E-02

IV

 Citalopram

11

67,622

0.21

1.26 (1.05,1.50)

(0.82,1.94)

45.51

0.29

1.04E-03

1.12E-02

IV

 Nitrate (high vs low)

4

912

0.14

1.20 (1.02,1.42)

(0.83,1.73)

0.00

1.00

3.28E-02

3.28E-02

IV

 β-blockers (in the first trimester)

8

59,756

0.72

1.57 (1.11,2.23)

(0.59,4.18)

65.02

0.99

2.17E-06

1.08E-02

IV

 Bupropion

3

6591

0.63

1.23 (1.01,1.49)

(0.35,4.31)

0.00

1.00

3.58E-02

3.58E-02

IV

 Fluconazole (in the first trimester)

5

6716

0.44

1.95 (1.18,3.21)

(0.35,10.78)

78.00

0.11

1.18E-07

8.97E-03

IV

 Gestational hypertension

23

138,067

0.13

1.73 (1.48,2.03)

(0.85,3.51)

79.93

0.83

3.92E-128

1.19E-11

II

 GDM

26

99,010

0.11

1.94 (1.59,2.35)

(0.82,4.57)

88.99

0.01

3.24E-114

3.82E-11

II

 PGDM

30

139,743

0.04

3.13 (2.65,3.69)

(1.42,6.88)

79.39

0.79

0.00E+ 00

2.74E-41

II

 DM

50

166,545

0.00

2.60 (2.65,3.01)

(1.09,6.24)

97.66

0.00

8.18E-61

1.69E-38

II

 Fever

16

37,269

0.00

1.46 (1.21,1.76)

(0.75,2.85)

80.29

0.00

5.07E-05

7.76E-05

III

 Chronic diseases before pregnancy

3

346

0.99

4.33 (2.28,8.23)

(0.07,227.22)

0.00

0.45

7.40E-06

7.40E-06

IV

 Infection of the reproductive system

3

2742

0.01

4.57 (1.10,18.92)

(0.00,3000.00)

65.91

0.27

1.92E-03

3.61E-02

IV

 Respiratory infection

5

653

0.28

3.79 (2.32,6.19)

(0.94,15.24)

57.54

0.69

1.26E-16

1.02E-07

IV

 Malnutrition during pregnancy

4

538

0.14

1.96 (1.33,2.88)

(0.46,8.42)

48.51

0.01

2.51E-06

6.40E-04

IV

 Influenza

8

6956

0.18

1.73 (1.10,2.71)

(0.59,5.03)

52.16

0.99

2.36E-06

1.73E-02

IV

 Rubella virus

7

332

0.46

3.30 (2.36,4.62)

(2.13,5.12)

46.53

0.05

2.85E-12

2.86E-12

IV

 Cytomegalovirus infection

4

119

0.42

3.95 (1.75,8.90)

(0.53,29.38)

53.34

0.33

3.28E-04

9.43E-04

IV

 Viral infection

17

6401

0.15

2.53 (1.40,4.56)

(0.23,27.47)

77.67

0.38

1.91E-15

2.15E-03

IV