Table 1 Social, medical and obstetric factors of Northern Territory women who birthed in 2001–2012 by Aboriginal status and induction of labour status

Maternal age

 Less than 20 years

25.6

25.1

1.05 (0.93, 1.18)

4.0

4.4

0.88 (0.76, 1.01)

 20 to 24 years

28.3

32.9

0.89 (0.79, 0.99)

16.6

16.0

1.00 (0.92, 1.09)

 25 to 29 years

21.9

22.6

1.00

29.8

28.8

1.00

 30 to 34 years

15.5

12.9

1.25 (1.09, 1.42)

30.4

31.1

0.95 (0.88, 1.02)

 35 years and over

8.7

6.5

1.37 (1.17, 1.62)

19.1

19.7

0.94 (0.86, 1.02)

Marriage status

 Single

49.7

54.5

0.83 (0.76, 0.89)

17.3

17.8

1.02 (0.94, 1.09)

 Married/defacto

45.2

41.0

1.00

63.8

66.6

1.00

 Other

5.2

4.6

1.03 (0.85, 1.24)

18.9

15.6

1.26 (1.17, 1.36)

Parity

 First-time mother

40.4

28.9

1.86 (1.70, 2.05)

51.4

41.3

1.55 (1.46, 1.65)

 1-2 previous births

34.3

45.6

1.00

39.8

49.7

1.00

 ≥3 previous births

25.3

25.5

1.32 (1.19, 1.47)

8.7

8.9

1.22 (0.25, 0.27)

Place of birth

 Public hospital

98.9

94.4

1.00

62.5

70.9

1.00

 Private hospital

1.1

0.6

1.71 (1.21, 2.70)

37.5

26.9

1.58 (1.49, 1.68)

 Other

0.0

5.0

NA^a

0.0

2.2

0.02 (0.00, 0.06)

Residence of mother

 Urban

30.0

28.7

1.00

88.9

87.8

1.00

 Remote

70.0

71.3

0.94 (0.86, 1.03)

11.1

12.2

0.90 (0.82, 0.98)

Medical and obstetric factors^b

 Multiple pregnancy

0.8

0.9

0.88 (0.56, 1.38)

1.0

1.3

0.72 (0.55, 0.95)

 Early antenatal visit

47.8

43.3

1.20 (1.11, 1.30)

77.1

74.1

1.18 (1.10, 1.26)

 Previous caesarean section

7.4

20.4

0.31 (0.27, 0.36)

3.6

17.9

0.17 (0.15, 0.19)

 Smoked during pregnancy

38.1

44.8

0.76 (0.70, 0.82)

15.0

16.7

0.88 (0.81, 0.95)

 Diabetes in pregnancy

17.4

8.0

2.42 (2.16, 2.71)

7.6

5.2

1.51 (1.35, 1.68)

 Maternal hypertension

7.5

2.5

3.13 (2.62, 3.73)

4.5

1.2

4.00 (3.36, 4.76)

 Pre-eclampsia

14.4

3.1

5.27 (4.56, 6.07)

8.5

2.0

4.59 (4.02, 5.23)

 Antepartum haemorrhage

1.6

1.7

0.93 (0.68, 1.27)

2.1

2.4

0.88 (0.73, 1.07)

 Malpresentation

1.0

4.9

0.19 (0.13, 0.28)

1.1

6.0

0.18 (0.14, 0.23)

 Preterm delivery

10.4

12.3

0.83 (0.73, 0.94)

3.8

6.3

0.58 (0.51, 0.67)

 Late term (≥41 weeks)

24.4

5.9

5.18 (4.64, 5.79)

27.9

8.5

4.15 (3.86, 4.46)

 Premature rupture of membranes

5.8

2.8

2.10 (1.74, 2.53)

2.2

1.4

1.63 (1.33, 2.00)

 Prolonged rupture of membranes

16.5

3.1

6.20 (5.39, 7.12)

9.3

1.7

6.04 (5.27, 6.92)

 Intrauterine growth retardation

18.5

17.7

1.05 (0.95, 1.17)

9.3

9.3

1.00 (0.91, 1.10)

 Macrosomia

10.8

6.7

1.69 (1.47, 1.93)

16.0

10.9

1.55 (1.43, 1.68)