Table 4 Odds ratio and corresponding 95% confidence intervals from a multinomial logistic regression for instrumental delivery, emergency CS and elective CS compared to vaginal delivery, adjusted for all variables presented in the table

25-29.9

1.02 (0.33-3.12)

0.976

≥30

Reference

Group

Index

0.94 (0.47-1.87)

0.852

Reference

Reference

Age

<25

0.44 (0.16-1.24)

0.121

25-34

0.88 (0.39-1.95)

0.465

≥35

Reference

Smoking

No

0.88 (0.39-1.95)

0.744

Yes

Reference

Complications during pregnancy

No

2.17 (0.78-6.05)

0.137

Yes

Reference

Emergency CS

BMI

<25

0.56 (0.21-1.47)

0.242

25-29.9

0.90 (0.31-2.67)

0.855

≥30

Reference

Group

Index

1.44 (0.67-3.09)

0.346

Reference

Reference

Age

<25

0.49 (0.16-1.49)

0.208

25-34

0.74 (0.32-1.73)

0.490

≥35

Reference

Smoking

No

0.80 (0.32-2.01)

0.638

Yes

Reference

Complications during pregnancy

No

0.15 (0.07-0.32)

<0.001

Yes

Reference

Elective CS

BMI

<25

1.54 (0.39-3.10)

0.540

25-29.9

0.92 (0.17-4.99)

0.924

≥30

Reference

Group

Index

12.16 (4.43-33.34)

<0.001

Reference

Reference

Age

<25

0.65 (0.16-2.73)

0.559

25-34

0.72 (0.22-2.34)

0.584

≥35

Reference

Smoking

No

1.06 (0.35-3.19)

0.915

Yes

Reference

Complications during pregnancy

No

0.18 (0.07-0.46)

<0.001

Yes

Reference