Method | RR (95% CI) | ||
---|---|---|---|
Cesarean delivery | Forceps- or vacuum-assisted vaginal delivery | All procedural deliveries | |
Logistic regression | |||
Bivariate | 0.33 (0.27-0.40) | 1.02 (0.91-1.13) | 0.35 (0.31-0.40) |
Multivariate* | 0.48 (0.41-0.56) | 1.00 (0.92-1.09) | 0.61 (0.56-0.67) |
Instrumental-variable-adjusted regression | |||
Bivariate | 0.96 (0.79-1.17) | 0.92 (0.74-1.12) | 0.94 (0.82-1.09) |
Multivariate* | 1.27 (1.02-1.57) | 1.03 (0.82-1.29) | 1.16 (0.99-1.35) |
Note: CI = confidence interval, RR = relative risk.
*Multivariate adjusted models controlled for all comorbidities listed in Appendix 1.