Table 3: Relative risk of cesarean delivery, forceps- or vacuum-assisted vaginal delivery and all procedural deliveries for family physicians versus obstetricians on logistic and instrumental-variable-adjusted regression
MethodRR (95% CI)
Cesarean deliveryForceps- or vacuum-assisted vaginal deliveryAll procedural deliveries
Logistic regression
    Bivariate0.33 (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
    Bivariate0.96 (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.