Table 4 Logistic regression-based Attributable Fraction (AF), Stratum-specific Total Attributable Fraction (sTAF) and overall Total Attributable Fraction (TAF) of not attending any antenatal visit, insufficient antenatal visit (<4 visits) and lack of skilled attendant at birth in each stratum from 1988 to 2008 presented in 5 years intervals

Residence ^*

 Urban

Ref

Ref

Ref

Ref

 Rural

0.73 (0.68)

0.52 (0.47)

0.62 (0.59)

0.44 (0.39)

 TAF

0.68

0.47

0.59

0.39

 p-value

0.000

0.035

0.001

0.211

Highest educational level ^*

 No education

0.94 (0.68)

0.92 (0.70)

-

0.41 (0.21)

 Basic education

0.76 (0.20)

0.77 (0.18)

0.16 (0.08)

 Secondary+

Ref

Ref

Ref

 TAF

0.88

0.88

0.29

 p-value

0.000

0.000

0.439

Income level ^*

 Low income

No data

0.17 (0.09)

0.47 (0.39)

0.68 (0.54)

 Average income

-

0.23 (0.03)

0.47 (0.06)

 High income

Ref

Ref

Ref

 TAF

0.09

0.42

0.60

 p-value

0.455

0.095

0.056

Parity*

 Nulliparous

Ref

Ref

Ref

Ref

 Para 1-3

0.38 (0.19)

0.16 (0.07)

0.09 (0.04)

0.67 (0.32)

 Para 4+

0.38 (0.14)

0.16 (0.07)

0.50 (0.24)

0.82 (0.36)

 TAF

0.33

0.14

0.28

0.68

 p-value

0.151

0.832

0.026

0.007

Less than four antenatal visits

1988

1993

1998

2003

2008

AF (sTAF)

AF (sTAF)

AF (sTAF)

AF (sTAF)

AF (sTAF)

Residence ^*

 Urban

Ref

Ref

Ref

Ref

 Rural

0.71 (0.62)

0.57 (0.50)

0.58 (0.52)

0.33 (0.28)

 TAF

0.62

0.50

0.52

0.28

 p-value

0.000

0.000

0.000

0.013

Highest educational level ^*

 No education

0.90 (0.50)

0.90 (0.52)

0.77 (0.47)

0.55 (0.28)

 Basic education

0.77 (0.34)

0.82 (0.33)

0.62 (0.23)

0.33 (0.16)

 Secondary+

Ref

Ref

Ref

Ref

 TAF

0.84

0.85

0.70

0.44

 p-value

0.000

0.000

0.000

0.006

Income level ^*

 Low income

No data

0.33 (0.18)

0.57 (0.40)

0.71 (0.52)

 Average income

0.16 (0.04)

0.57 (0.11)

0.64 (0.10)

 High income

Ref

Ref

Ref

 TAF

0.22

0.51

0.62

 p-value

0.002

0.000

0.000

Parity*

 Nulliparous

Ref

Ref

Ref

Ref

 Para 1-3

0.09 (0.04)

0.33 (0.15)

0.23 (0.10)

0.44 (0.21)

 Para 4+

0.23 (0.08)

0.50 (0.19)

0.57 (0.23)

0.71 (0.26)

 TAF

0.12

0.34

0.33

0.47

 p-value

0.423

0.007

0.000

0.000

Lacked skilled attendant at birth

1988

1993

1998

2003

2008

AF (sTAF)

AF (sTAF)

AF (sTAF)

AF (sTAF)

AF (sTAF)

Residence ^*

 Urban

Ref

Ref

Ref

Ref

Ref

 Rural

0.77 (0.66)

0.88 (0.80)

0.77 (0.70)

0.66 (0.59)

0.58 (0.50)

 TAF

0.66

0.80

0.70

0.59

0.50

 p-value

0.000

0.000

0.000

0.000

0.000

Highest educational level ^*

 No education

0.80 (0.44)

0.85 (0.46)

0.85 (0.51)

0.84 (0.49)

0.73 (0.38)

 Basic education

0.55 (0.23)

0.55 (0.24)

0.62 (0.24)

0.68 (0.26)

0.47 (0.22)

 Secondary+

Ref

Ref

Ref

Ref

Ref

 TAF

0.67

0.70

0.75

0.75

0.60

 p-value

0.000

0.000

0.000

0.000

0.000

Income level ^*

No data

 Low income

0.41 (0.20)

0.41 (0.20)

0.77 (0.57)

0.77 (0.59)

 Average income

0.23 (0.04)

0.09 (0.02)

0.63 (0.11)

0.52 (0.07)

 High income

Ref

Ref

Ref

Ref

 TAF

0.24

0.22

0.68

0.66

 p-value

0.000

0.001

0.000

0.000

Parity*

 Nulliparous

Ref

Ref

Ref

Ref

Ref

 Para 1-3

0.38 (0.17)

0.44 (0.22)

0.47 (0.21)

0.44 (0.20)

0.44 (0.16)

 Para 4+

0.38 (0.15)

0.50 (0.17)

0.71 (0.28)

0.62 (0.24)

0.62 (0.20)

 TAF

0.32

0.39

0.49

0.44

0.36

 p-value

0.007

0.001

0.000

0.000

0.001