Long-term anal incontinence after obstetric anal sphincter injury-does grade of tear matter?

Anal incontinence is a major concern following delivery with obstetric anal sphincter injury (OASIS), and has been related to the degree of sphincter tear.

The aims of this study were (1) to evaluate whether women with a fourth-degree OASIS in the first delivery have an increased risk of long-term anal and fecal incontinence after a second delivery, and (2) to assess the impact of mode of second delivery on anal incontinence and related symptoms in these patients.

We performed secondary analyses of a national questionnaire study in all Danish women with an OASIS in their first delivery and 1 subsequent delivery, both deliveries in 1997 to 2005. The questionnaires were sent a minimum of 5 years since the second delivery. In Denmark, women with anal incontinence after a delivery with OASIS are recommended elective cesarean deliveries in subsequent pregnancies. We performed uni- and multivariable logistic regression analyses to evaluate the outcomes.

In total, 2008 patients had an OASIS, of whom 12.2% (n = 245) had a fourth-degree tear in the first delivery. The median follow-up time since the first delivery with OASIS was 11.6 years (IQR, 10.2-13.2 years) and since the second delivery 8.5 years (IQR, 7.1-10.1 years). Women with a fourth-degree sphincter injury in the first delivery were at higher risk for anal incontinence (58.8%, n = 144) as well as fecal incontinence (30.6%, n = 75) than patients with a third-degree injury in the first delivery (41.0%, n = 723, and 14.6%, n = 258, respectively). The differences between groups persisted after adjustment for important maternal, fetal, and obstetric characteristics (adjusted odds ratio [aOR], 2.14; 95% confidence interval [CI], 1.52-3.02; P < 0.001 for anal incontinence; and aOR, 2.49; 95% CI, 1.73-3.56; P < 0.001 for fecal incontinence). In subgroup analyses of patients with fourth-degree anal sphincter injury in the first delivery, the mode of second delivery was not associated with the risk of anal incontinence (aOR, 0.97; 95% CI, 0.41-1.84; P = 0.71) or fecal incontinence (aOR, 1.28; 95% CI, 0.65-2.52; P = 0.48). The effect of the mode of the second delivery did not differ between women with a fourth-degree OASIS and those with a third-degree injury with regard to both anal (P = 0.09) and fecal (P = 0.96) incontinence.

After a second delivery, women with a fourth-degree OASIS in the first delivery have a higher risk of long-term anal and fecal incontinence than women with a third-degree sphincter injury. Adjusted odds of long-term anal and fecal incontinence did not differ significantly by mode of second delivery. Women with a fourth-degree OASIS should be informed about the increased risk of long-term anal incontinence and advised that subsequent elective cesarean delivery is not protective.