Do occult anal sphincter injuries, vector volume manometry and delivery variables have any predictive value for bowel...

The aim of this study was to determine whether there exists a correlation between anal incontinence, occult sphincter injuries, anal manometry values, and delivery variables in primiparous women after first time vaginal delivery.

Eighty-six primigravida women were recruited for this study. Transanal ultrasonography (TAUS) and vector volume manometry (VVM) was performed and bowel symptoms were recorded at 25 weeks of pregnancy and 5 months after labor. Incontinent women at 5 months after vaginal delivery were interviewed again at 12 months.

Nineteen women (25%) experienced flatus incontinence postpartum. After 12 months, only one-third of the women were still incontinent. Fourteen women (19%) showed abnormal TAUS of the anal sphincter. Of the delivery variables, only baby head circumference was significantly associated with flatus incontinence (p = 0.01). There was no correlation between flatus incontinence or delivery variables and anal sphincter injuries; VVM values were not associated with either anal sphincter injuries or flatus incontinence at 5 months, but VVM values were negatively associated with flatus incontinence at 12 months after labor.

At 5 months after labor, flatus incontinence is relatively common, and is not associated with reduced VVM values. Two-thirds of women recover from flatus incontinence during the first year. Women who had flatus incontinence persisting for a minimum of 1 year had reduced VVM values. Anal sphincter injuries as seen by TAUS are not associated with either VVM values or any delivery variable. Baby head circumference is the only delivery variable significantly associated with flatus incontinence.