The team examined the prevalence and possible causes of anal incontinence in a large cohort of women, and published their findings in the latest issue of the Canadian Medical Association Journal.
A total of 949 pregnant women, who gave birth in 5 hospitals in 1995-1996 in the province of Quebec, were studied.
These women, participants in a randomized controlled trial of prenatal perineal massage, completed a self-administered questionnaire 3 months after giving birth.
Three months after delivery, 29 women (3%) reported incontinence of stool, and 242 (26%) had involuntary escape of flatus.
Incontinence of stool was more frequent among women who delivered vaginally and had third- or fourth-degree perineal tears, than among those who delivered vaginally and had no anal sphincter tears (8% vs 3%).
|Anal sphincter injury linked with:|
- First vaginal birth
- Median episiotomy
- Forceps and vacuum delivery
| Canadian Medical Association Journal |
Forceps delivery (adjusted risk ratio [RR] 1.45) and anal sphincter tears (adjusted RR 2.09) were independent risk factors for incontinence of flatus or stool or both.
Anal sphincter injury was strongly and independently associated with first vaginal birth (RR 39.2), median episiotomy (adjusted RR 9.6), forceps delivery (adjusted RR 12.3), and vacuum-assisted delivery (adjusted RR 7.4).
However, it was not found to be associated with birth weight (adjusted RR for birth weight 4 kg or more: 1.4) or length of the second stage of labor (adjusted RR for second stage 1.5 hours or longer compared with less than 0.5 hours: 1.2).
Dr Erica Eason, of the University of Ottawa, Ontario, concluded on behalf of her colleagues, "Anal incontinence is associated with forceps delivery and anal sphincter laceration.
"Anal sphincter laceration is strongly predicted by first vaginal birth, median episiotomy, and forceps or vacuum delivery, but not by birth weight or length of the second stage of labor."