Skip to main content

Table 5 Demographic, medical and obstetric characteristics and preterm births among non-ART singleton birth mothers, Australia, 2007–2009

From: Risk factors associated with preterm birth among singletons following assisted reproductive technology in Australia 2007–2009–a population-based retrospective study

Characteristics

All singleton births (N = 381,345)

Preterm births

No.

%

OR (95% CI)

AOR (a)(95% CI)

Maternal age

     

Less than 25

76,182

6,012

7.9

1.27 (1.23–1.31)

1.12 (1.08–1.16)

25-34

223,494

14,130

6.3

1

1

35-44

81,216

5,673

7.0

1.11 (1.08–1.15)

1.13 (1.09–1.17)

45 and over

439

44

10.0

1.65 (1.21–2.25)

1.49 (1.08–2.06)

Smoking status during pregnancy

    

Smoked

47,179

4,569

9.7

1.64 (1.59–1.70)

1.55 (1.50–1.61)

Did not smoke

196,661

12,050

6.1

1

1

Maternal country of birth

    

Overseas

85,083

5,464

6.4

0.93 (0.90–0.96)

NS

Australia

294,196

20,211

6.9

1

 

SEIFA Index of Disadvantage

     

1 (Most disadvantaged)

78,473

5,919

7.5

1.28 (1.23–1.34)

1.14 (1.09–1.19)

2

62,969

4,565

7.3

1.23 (1.18–1.28)

1.11 (1.06–1.17)

3

83,153

5,543

6.7

1.12 (1.08–1.17)

1.05 (1.00–1.10)

4

87,116

5,516

6.3

1.06 (1.02–1.11)

1.02 (0.98–1.07)

5 (Least disadvantaged)

66,987

4,007

6.0

1

1

Parity

     

Primiparous

154,519

11,397

7.4

1.17 (1.14–1.20)

1.13 (1.10–1.17)

Multiparous

226,826

14,474

6.4

1

1

Remoteness

     

Major cities

244,632

15,951

6.5

1

1

Inner regional

80,205

5,732

7.2

1.10 (1.07–1.14)

1.00 (0.97–1.04)

Outer regional

44,867

3,216

7.2

1.11 (1.06–1.15)

1.01 (0.96–1.05)

Remote

7,082

528

7.5

1.15 (1.06–1.26)

1.04 (0.95–1.14)

Very remote

4,252

371

8.7

1.37 (1.23–1.53)

1.13 (1.01–1.27)

Health insurance

    

Public

256,511

18,612

7.3

1

1

Private

122,987

7,207

5.9

0.80 (0.77–0.82)

0.89 (0.86–0.92)

Essential hypertension

     

Yes

3,468

511

14.7

2.41 (2.19–2.65)

2.05 (1.86–2.27)

No

371,934

24,921

6.7

1

1

Diabetes mellitus

     

Yes

2,447

606

24.8

4.62 (4.21–5.06)

4.13 (3.75–4.56)

No

372,954

24,826

6.7

1

1

Epilepsy

     

Yes

2,007

219

10.9

1.10 (1.00–1.21)

1.49 (1.29–1.73)

No

373,395

25,213

6.8

1

1

Hypertensive disorders in pregnancy

    

Yes

16,850

2,778

16.5

2.92 (2.80–3.05)

2.94 (2.81–3.08)

No

364,495

23,093

6.3

1

1

Gestational diabetes

     

Yes

19,075

1,639

8.6

1.31 (1.24–1.38)

1.27 (1.20–1.34)

No

362,270

24,232

6.7

1

1

Antepartum haemorrhage

    

Yes

10,699

3,311

31.0

6.92 (6.62–7.22)

7.11 (6.80–7.43)

No

370,632

22,557

6.1

1

1

  1. (a) Stepwise multiple logistic regression model adjusted for maternal age, country of birth, smoking status during pregnancy, SEIFA, parity, health insurance type, remoteness, essential hypertension, diabetes mellitus, epilepsy, hypertensive disorders in pregnancy, gestational diabetes and antepartum haemorrhage.
  2. NS: statistically not significant.