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

From: Socioeconomic risk factors for labour induction in the United Kingdom

 Model 1
N = 6723
Model 2
N = 6305
Odds Ratio95% CIp-valueOdds Ratio95% CIp-value
Maternal Age
 19 years and under0.721*0.551, 0.9430.0170.7550.561, 1.0150.063
 20–25 years old0.7950.630, 1.0030.0530.722*0.560, 0.9320.012
 26–30 years old0.8400.677, 1.0410.1110.766*0.606, 0.9700.027
 31–35 years old0.9610.768, 1.2010.7260.9110.713, 1.1630.454
 36 years and olderRefRefRefRefRefRef
Maternal Ethnicity
 WhiteRefRefRefRefRefRef
 Indian0.9100.624, 1.3260.6231.3670.898, 2.0810.144
 Pakistani/Bangladeshi0.9710.697, 1.3530.8631.2650.865, 1.8500.225
 Black/Black British0.8860.628, 1.2510.4930.8760.589, 1.3030.514
 Other0.8330.597, 1.1620.2821.0400.726, 1.4900.832
Maternal Marital Status
 Legally MarriedRefRefRefRefRefRef
 Cohabiting1.0270.901, 1.1720.6871.0430.902, 1.2060.567
 Unpartnered0.9160.703, 1.1940.5160.9520.713, 1.2720.740
Maternal Education
 Higher/first degreesRefRefRefRefRefRef
 Diplomas in higher education1.1040.907, 1.3440.3231.1360.918, 1.4080.241
 A/O Levels (GSCE A-C)1.1450.985, 1.3310.0781.200*1.107, 1.4150.031
 Other (incl. GCSE D-G)1.0820.883, 1.3250.4481.2080.965, 1.5110.098
 None1.2020.960, 1.5060.1091.353*1.054, 1.7370.018
Electoral Ward Deprivation
 England – AdvantagedRefRefRefRefRefRef
 England – Disadvantaged1.0740.929, 1.2410.3361.0590.904, 1.2400.480
 England – Ethnic1.1540.902, 1.4770.2561.2000.910, 1.5810.196
 Wales – Advantaged0.9070.703, 1.1700.4520.8500.642, 1.1260.257
 Wales – Disadvantaged1.1010.913, 1.3280.3121.0980.896, 1.3460.367
 Scotland – Advantaged1.2030.975, 1.4830.0851.309*1.041, 1.6460.021
 Scotland – Disadvantaged1.303**1.060, 1.6030.0121.393**1.112, 1.7450.004
 N. Ireland – Advantaged2.021***1.563, 2.6140.0002.560***1.947, 3.3660.000
 N. Ireland – Disadvantaged1.2000.953, 1.5090.1211.377*1.072, 1.7680.012
Pregnancy Complications
 No pregnancy complications   RefRefRef
 Complications not associated with induction   1.276**1.101, 1.4790.001
 Complications associated with induction   2.653***2.281, 3.0850.000
 Other   1.409**1.097, 1.8090.007
Maternal BMI
 Low (< 18.5)   RefRefRef
 Normal (18.5–24.9)   0.9710.771, 1.2210.799
 High (≥25.0)   1.305*1.109, 1.6700.035
Infant Birth Weight
 Low (< 2500 g)   0.9990.776, 1.2860.995
 Normal (2500–4000 g)   RefRefRef
 High (> 4000 g)   1.325**1.094, 1.6030.004
Infant Gestational Age
 259 days or less   0.9540.764, 1.1910.676
 260–272 days   1.0440.879, 1.2400.624
 273–286 days   RefRefRef
 287–293 days   3.058***2.675, 3.5000.000
 294 days or more   8.049***6.039, 10.7270.000
  1. Model 1 was adjusted for maternal occupation, housing tenure, and income quintile
  2. Model 2 was adjusted for maternal occupation, housing tenure, income quintile, and smoking behaviour
  3. *P < 0.05 **P < 0.01 ***P < 0.001