Risk Factors for Anal Continence Impairment Following a Second Delivery after a First Traumatic Delivery: A Prospective Cohort Study.

Postpartum anal incontinence is common. After a first delivery (D1) with perineal trauma, follow-up is advised to reduce the risk of anal incontinence. Endoanal sonography (EAS) may be considered to evaluate the sphincter and in case of sphincter lesions to discuss cesarean section for the second delivery (D2). Our objective was to study the risk factors for anal continence impairment following D2. Women with a history of traumatic D1 were followed before and 6 months after D2. Continence was measured using the Vaizey score. An increase ≥2 points after D2 defined a significant deterioration. A total of 312 women were followed and 67 (21%) had worse anal continence after D2. The main risk factors for this deterioration were the presence of urinary incontinence and the combined use of instruments and episiotomy during D2 (OR 5.12, 95% CI 1.22-21.5). After D1, 192 women (61.5%) had a sphincter rupture revealed by EAS, whereas it was diagnosed clinically in only 48 (15.7%). However, neither clinically undiagnosed ruptures nor severe ruptures were associated with an increased risk of continence deterioration after D2, and cesarean section did not protect against it. One woman out of five in this population had anal continence impairment after D2. The main risk factor was instrumental delivery. Caesarean section was not protective. Although EAS enabled the diagnosis of clinically-missed sphincter ruptures, these were not associated with continence impairment. Anal incontinence should be systematically screened in patients presenting urinary incontinence after D2 as they are frequently associated.