Risk Factors for Obstetric Anal Sphincter Injuries among Women Delivering at a Tertiary Hospital in Southwestern Uganda

Table 3

Risk factors for anal sphincter injuries (OASIS) in multivariable and univariable logistic regression analyses.

Characteristic	% of cases	Univariable analysis	value	Multivariable analysis	value
	n/N (%)	OR (95%CI)		Adjusted OR (95%CI)
Age category (years)
≤ 25	60/148 (40.5)	Ref	0.003	Ref	0.963
>25	20/92 (21.7)	0.41 (0.22–0.74)		0.98 (0.40–2.39)
Income in Ugx
50 k or less	76/159 (47.8)	Ref	0.001	Ref	<0.001
More than 50 k	4/68 (5.9)	0.07 (0.02–0.20)		0.09 (0.03–0.28)
Gravidity
Multigravida	30/145 (20.7)	Ref	0.001	Ref	0.068
Prime gravida	50/94 (53.2)	4.35 (2.46–7.71)		2.40 (0.94–6.14)
Duration of 2nd stage of labour
<1 hour	64/205 (31.2)	Ref	<0.001	Ref	0.003
≥1 hour	20/29 (69.0)	4.90 (2.11–11.34)		6.07 (1.86–19.82)
Performed episiotomy
No	26/150 (26.0)	Ref	0.004	Ref	0.035
Yes	33/73 (45.2)	2.35 (1.30–4.23)		2.57 (1.07–6.17)
Perineum supported
No	30/37 (81.1)	Ref	0.001	Ref	<0.001
Yes	41/191 (22.0)	0.07 (0.03–0.16)		0.03 (0.01–0.12)

K = 1,000 shillings; Ugx = Ugandan shillings; Ref = reference category.