BioMed Research International / 2014 / Article / Tab 1

Research Article

Maternal Body Mass Index and Risk of Obstetric Anal Sphincter Injury

Table 1

Risk factors for any anal sphincter injury among primiparous women with singleton vaginal cephalic births at term. OR for each variable studied in relation to anal sphincter injury was adjusted for all other variables and for year of delivery.

Reference population ( )Anal Sphincter injury ( )%Adjusted OR95% CI

Maternal body mass index
 Unknown5052133516.60.960.93–1.00
 Less than 18.5121547846.51.311.23–1.41
 18.5–24.9260037172516.61.00Reference
 25–29.98263855926.80.920.89–0.95
 30–34.92273314436.30.870.82–0.92
 35–39.963623715.80.770.69–0.85
 40 or more20371236.00.750.65–0.90
Maternal age, y
 Younger than 20183273952.10.350.32–0.39
 20–249874942764.20.650.63–0.68
 25–29162898114836.61.00Reference
 30–3411803797167.61.131.10–1.16
 35–393352827027.51.071.03–1.12
 40–4448033376.60.910.81–1.02
 45 or older14064.10.520.22–12.3
Fetal head position
 Occipitoanterior position420006270046.41.00Reference
 Occipitoposterior position13955159611.41.361.29–1.44
 Other252131512.51.541.34–1.74
Instrumental delivery
 No368519181704.91.00Reference
 Yes679631074515.82.742.67–2.81
Infant birth weight
 Less than 30005555014242.50.800.75–0.85
 3000–349916705974154.21.00 Reference
 3500–3999155742118937.11.371.33–1.41
 4000–449950373655611.52.672.58–2.77
 4500–49997117144516.96.335.97–6.92
 5000 or more64118222.111.569.95–13.44

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