Table 3 Cox regression showing the hazard ratio (HR) of caesarean delivery comparing the defined BMI groups, with and without adjustment for covariates

 < 25

1

1

 25–29.9

1.39

[1.06–1.81]

1.28

[0.97–1.69]

 ≥ 30

1.94

[1.40–2.69]

1.80

[1.28–2.54]

 < 160 cm

1

1

 160–169 cm

0.83

[0.60–1.15]

0.77

[0.55–1.09]

 170–179 cm

0.74

[0.52–1.05]

0.64

[0.44–0.93]

 ≥ 180 cm

0.67

[0.31–1.41]

0.50

[0.23–1.08]

 < 25

1

1

 25–29

0.99

[0.72–1.37]

0.97

[0.69–1.37]

 30–34

1.22

[0.88–1.68]

1.31

[0.94–1.84]

 ≥ 35

1.57

[1.08–2.29]

1.82

[1.22–2.69]

 < 3.0 kg

1

1

 3.0–3.5 kg

0.89

[0.56–1.41]

0.98

[0.59–1.61]

 3.5–4.0 kg

1.03

[0.67–1.59]

1.13

[0.71–1.82]

 > 4.0 kg

1.39

[0.87–2.18]

1.43

[0.87–2.36]

 No

1

1

 Yes

1.16

[0.88–1.53]

0.96

[0.72–1.29]

 No

1

1

 Yes

1.21

[0.85–1.72]

0.96

[0.65–1.42]

 No

1

1

 Yes

1.80

[1.43–2.27]

1.67

[1.33–2.17]

Crude HR

95% CI

Adjusted HR

95% CI

 < 25

1

1

 25–29.9

1.68

[1.07–2.66]

1.55

[0.97–2.48]

 ≥ 30

1.56

[0.86–2.84]

1.56

[0.84–2.89]

Crude HR

95% CI

Adjusted HR

95% CI

 < 25

1

1

 25–29.9

1.22

[0.77–1.94]

1.08

[0.67–1.74]

 ≥ 30

1.56

[0.86–2.84]

1.56

[0.84–2.89]