Table 1 Summary of characteristics of included studies

Total

91

[27, 45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135]

Language of publication

Persian

55

[45, 55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89, 103,104,105,106,107,108,109,110, 114,115,116,117,118,119,120, 122, 123, 127, 129, 130]

English

36

[27, 46,47,48,49,50,51,52,53,54, 90,91,92,93,94,95,96,97,98,99,100,101,102, 111,112,113, 121, 124,125,126, 128, 131,132,133,134,135]

Year of data collection

1999–2010

18

[47, 50, 54, 60,61,62, 65, 75,76,77, 79, 81, 83,84,85,86,87, 124]

2011 or 2019

56

[27, 45, 46, 48, 55,56,57, 64, 67, 72, 73, 78, 82, 90,91,92,93,94,95, 97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123, 125,126,127,128,129,130,131,132,133,134,135]

Not specified

17

[49, 51,52,53, 58, 59, 63, 66, 68,69,70,71, 74, 80, 88, 89, 96]

Study design

Quantitative study

65

[45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110]

 Longitudinal

1

[46]

 Cross-sectional

48

[45, 47,48,49,50,51,52,53,54, 57,58,59,60,61,62, 65,66,67,68,69, 72,73,74,75,76,77,78, 80,81,82,83,84, 86,87,88,89,90,91,92,93,94, 96, 98, 100, 102, 103, 107,108,109]

 Experiment (baseline)

15

[55, 56, 63, 64, 70, 71, 79, 85, 95, 97, 99, 101, 104,105,106]

Prospective cohort study

1

[110]

Qualitative study

26

[27, 111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135]

Location

Urban

80

[27, 45, 47, 48, 50,51,52,53,54,55,56, 58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77, 79,80,81,82,83,84,85,86,87,88,89, 92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112, 114, 117, 118, 120,121,122,123,124,125,126,127,128,129,130,131,132, 134, 135]

Rural

1

[57]

Mixed

3

[78, 116, 119]

Unknown

7

[46, 49, 90, 91, 115, 113, 133]

Population

Facility-based

89

[27, 45,46,47, 49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89, 91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135]

Population-based

1

[48]

Unknown

1

[90]

Participants

In quantitative study

Pregnant women (regardless parity)

33

[44,45,46,47, 52, 55, 56, 58,59,60, 62, 64, 65, 71,72,73, 75, 77,78,79, 82, 84, 85, 87, 91, 93, 97,98,99,100,101,102, 107]

Nulliparous

28

[43, 43,48,49,51, 53, 54, 57, 61, 63, 63,67,68,70, 74, 76, 83, 86, 89, 90, 92, 9, 96, 103,104,105,106,107]

Multiparous

3

[50, 90, 94]

Pregnant women with previous CS

2

[48, 88]

Mothers and husbands of women

1

[95]

Midwifes and doctors

3

[66, 81, 87]

In qualitative study

Women (pregnant, postpartum, NVD or CS, Nulliparous or Multiparous), healthcare providers ( midwife, physicians), husbands

26

Quality of quantitative included studies

65

Low

18

[45, 46, 48, 51, 57,58,59,60, 64, 71,72,73, 81, 83,84,85, 89]

Middle

5

[50, 69, 70, 77, 80]

High

41

[47, 49, 52,53,54,55,56, 61,62,63, 65,66,67,68, 74,75,76, 78, 79, 82, 86,87,88, 90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110]

Quality of qualitative included studies

26

[27, 111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135]

A: High

2

[27, 113]

B: Moderate

12

[117, 118, 121, 124,125,126, 128, 130, 132,133,134,135]

C: Low

10

[111, 114,115,116, 119, 120, 123, 129, 127, 131]

D: very low

2

[112, 122]