Mode of Vaginal Delivery: A Modifiable Intrapartum Risk Factor for Obstetric Anal Sphincter Injury

Table 4

Summary of multivariate analysis results.

Variable			Coeff.		OR	CI 95%; Lower OR	CI 95%; Upper OR
Neonatal weight (grams)			0.001	0.002	1.001	1.000	1.001
Mode of delivery	Spontaneous delivery				1
	Instrumental delivery	Vacuum	0.920	0.087	2.509	0.876	7.189
		Forceps	1.408	<0.001	4.089	2.406	6.949
		Thierry spatulas	1.569	<0.001	4.804	2.962	7.792

Reference group.