BioMed Research International / 2014 / Article / Tab 3

Research Article

Maternal Body Mass Index and Risk of Obstetric Anal Sphincter Injury

Table 3

The effect of fetal head position at delivery and the effect of instrumental delivery on the risk for any anal sphincter injury according to maternal body mass index among primiparous women with singleton vaginal cephalic births at term.

Maternal BMIOcciput posteriorOcciput anteriorOR*95% CIInstrumental vaginal deliverySpontaneous vaginal deliveryOR**95% CI
No anal sphincter injury ( )Anal sphincter injury ( )No anal sphincter injury ( )Anal sphincter injury ( )No anal sphincter injury ( )Anal sphincter injury ( )No anal sphincter injury ( )Anal sphincter injury ( )

Unknown158331404872031401.231.04–1.46210612454260121062.702.50–2.91
Less than 18.536132117757431.210.81–1.80482302104104823.122.68–3.14
18.5–24.98037959250460160991.441.34–1.55109496302220189109492.712.62–2.80
25–29.929722137915752211.191.05–1.35341921236896434192.782.62–2.94
30–34.9774962185313361.621.28–2.05875568192088753.152.81–3.54
35–39.92101961653511.270.77–2.0925911253672592.021.58–2.58
40 or more700195411480431700802.211.46–3.06

Adjustments were made for year of birth, maternal age, birth weight, and instrumental delivery. **Adjustments were made for year of birth, maternal age, birth weight, and fetal head position.

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