Table 4.

Multivariable logistic regression for vaginal delivery (adjusted).

Variable (coding/unit)	Regression coefficient (β)	OR	95% CI	Wald z	P value	VIF
Combined medication use (Yes vs. No)	0.65	1.92	1.10–3.34	z = 2.30	0.02	1.8
Age (per 1-year increase)	−0.01	0.99	0.93–1.05	z = −0.33	0.74	1.2
Gestational age (per 1-week increase)	0.03	1.03	0.86–1.25	z = 0.31	0.76	1.3
Bishop score at admission (per 1-point increase)	0.25	1.28	1.12–1.46	z = 3.65	<0.001	1.6
BMI (per 1 kg/m² increase)	−0.04	0.96	0.89–1.04	z = −1.03	0.30	1.4
Pregnancy complications (Yes vs. No)	−0.30	0.74	0.32–1.70	z = −0.71	0.48	1.2
Estimated fetal weight (per 100 g increase)	−0.09	0.91	0.84–0.99	z = −2.25	0.025	1.5