Table 3 Odds Ratios for Logistic Regression of Labour Induction: Nulliparous Women

 19 years and under

0.721*

0.551, 0.943

0.017

0.755

0.561, 1.015

0.063

 20–25 years old

0.795

0.630, 1.003

0.053

0.722*

0.560, 0.932

0.012

 26–30 years old

0.840

0.677, 1.041

0.111

0.766*

0.606, 0.970

0.027

 31–35 years old

0.961

0.768, 1.201

0.726

0.911

0.713, 1.163

0.454

 36 years and older

Ref

Ref

Ref

Ref

Ref

Ref

 White

Ref

Ref

Ref

Ref

Ref

Ref

 Indian

0.910

0.624, 1.326

0.623

1.367

0.898, 2.081

0.144

 Pakistani/Bangladeshi

0.971

0.697, 1.353

0.863

1.265

0.865, 1.850

0.225

 Black/Black British

0.886

0.628, 1.251

0.493

0.876

0.589, 1.303

0.514

 Other

0.833

0.597, 1.162

0.282

1.040

0.726, 1.490

0.832

 Legally Married

Ref

Ref

Ref

Ref

Ref

Ref

 Cohabiting

1.027

0.901, 1.172

0.687

1.043

0.902, 1.206

0.567

 Unpartnered

0.916

0.703, 1.194

0.516

0.952

0.713, 1.272

0.740

 Higher/first degrees

Ref

Ref

Ref

Ref

Ref

Ref

 Diplomas in higher education

1.104

0.907, 1.344

0.323

1.136

0.918, 1.408

0.241

 A/O Levels (GSCE A-C)

1.145

0.985, 1.331

0.078

1.200*

1.107, 1.415

0.031

 Other (incl. GCSE D-G)

1.082

0.883, 1.325

0.448

1.208

0.965, 1.511

0.098

 None

1.202

0.960, 1.506

0.109

1.353*

1.054, 1.737

0.018

 England – Advantaged

Ref

Ref

Ref

Ref

Ref

Ref

 England – Disadvantaged

1.074

0.929, 1.241

0.336

1.059

0.904, 1.240

0.480

 England – Ethnic

1.154

0.902, 1.477

0.256

1.200

0.910, 1.581

0.196

 Wales – Advantaged

0.907

0.703, 1.170

0.452

0.850

0.642, 1.126

0.257

 Wales – Disadvantaged

1.101

0.913, 1.328

0.312

1.098

0.896, 1.346

0.367

 Scotland – Advantaged

1.203

0.975, 1.483

0.085

1.309*

1.041, 1.646

0.021

 Scotland – Disadvantaged

1.303**

1.060, 1.603

0.012

1.393**

1.112, 1.745

0.004

 N. Ireland – Advantaged

2.021***

1.563, 2.614

0.000

2.560***

1.947, 3.366

0.000

 N. Ireland – Disadvantaged

1.200

0.953, 1.509

0.121

1.377*

1.072, 1.768

0.012

 No pregnancy complications

Ref

Ref

Ref

 Complications not associated with induction

1.276**

1.101, 1.479

0.001

 Complications associated with induction

2.653***

2.281, 3.085

0.000

 Other

1.409**

1.097, 1.809

0.007

 Low (< 18.5)

Ref

Ref

Ref

 Normal (18.5–24.9)

0.971

0.771, 1.221

0.799

 High (≥25.0)

1.305*

1.109, 1.670

0.035

 Low (< 2500 g)

0.999

0.776, 1.286

0.995

 Normal (2500–4000 g)

Ref

Ref

Ref

 High (> 4000 g)

1.325**

1.094, 1.603

0.004

 259 days or less

0.954

0.764, 1.191

0.676

 260–272 days

1.044

0.879, 1.240

0.624

 273–286 days

Ref

Ref

Ref

 287–293 days

3.058***

2.675, 3.500

0.000

 294 days or more

8.049***

6.039, 10.727

0.000