Clinical consequences of vaginal delivery with midline episiotomy and anal sphincter tear on anal continence in primiparae

Obstetric damage of the anorectal continence organ can lead to impaired anal continence. To assess the effect of birth, either with or without direct injury of the anal sphincter, 123 primiparae were studied. 41 patients with a midline episiotomy and 82 patients with an additional injury of the anal sphincter were assessed at a median of 21 weeks postpartum and compared with 18 healthy volunteers. Anorectal manometry as well as a standardized questionnaire were employed. Patients with an additional injury of the anal sphincter reported persistent flatus incontinence significantly more often (p = 0.0069) than patients with a midline episiotomy only. Incontinence of solid or liquid stool occurred only transiently. Compared to nulliparae in all primiparae a significant shortening of anal canal and a decreased squeeze pressure were observed. In addition, a significantly reduced resting pressure was seen in patients with an anal sphincter injury. The rectoanal inhibitory reflex was absent significantly more often following anal sphincter tear (p = 0.0023). Vaginal delivery, both with and without anal sphincter injury, leads to early detectable changes in anorectal sphincter function.