Obstetric risk factors for early-onset anal incontinence

The aim of the study was to identify primiparous pregnant women with a higher risk for early anal incontinence (AI) after labour.

In the retrospective case control study, 133 primiparous women were questioned using the Wexner scoring system, and possible obstetric anal sphincter injuries (OASIS) were assessed using endoanal ultrasonography (EUS) 6-12 weeks after the labour. Obstetric characteristics (possible risk factors) for AI were collected from the maternal medical records. The univariate and multiple regression of maternal, neonatal and labour risk factors were calculated. Cut-off values were set to divide women into groups with higher and lower risk for AI.

The data of 30 primiparous women with and 103 without AI were analysed. Univariate logistic regression of obstetrics characteristics showed that stimulation of labour (RO [95% CI] 3.31 [1.07, 10.28]) and neonatal head circumference (RO [95% CI] 1.36 [1.03, 1.78]) are both associated with AI. With a neonatal head circumference of 34 cm or more (cut-off value), probability for AI was 33%, while below that value, it was just 2%. The incidence of AI was not significantly different between women with surgically repaired OASIS and women without anal sphincter injury.

The findings can assist in the identification of pregnant women at higher risk of AI. The women at higher risk of AI should be given special attention during the labour and specific rehabilitation after the labour.