Researchers from Mexico determined the incidence of anal sphincter injury and fecal incontinence after vaginal delivery.
A total of 98 healthy primiparous females were included in the prospective, observational study. All had previously intact anal sphincter and normal continence, and were without history of anorectal surgery.
Each subject completed a continence questionnaire, and underwent endoanal ultrasound 4-6 weeks before, and 6 weeks after delivery.
The women had either instrumental (vacuum or forceps) vaginal delivery (n = 23) or non-instrumental vaginal delivery (n = 75).
| Patients with anal sphincter tears:|
Instrumental vaginal delivery 48%
Non-instrumental delivery 12%
| Diseases of the Colon & Rectum |
Some 20 patients had clinical sphincter tears that required primary repair. These tears occurred in 11 (48%) after instrumental delivery and 9 (12%) after non-instrumental vaginal delivery.
The researchers found that 28 patients (29%) had ultrasonographic defects that involved the external sphincter (n = 19) or both the internal and external sphincter (n = 9). Of these individuals, 19 had previously repaired sphincter injury.
In addition, 21 patients (75%) with ultrasonographic sphincter defects had either major (n = 5) or minor (n = 16) fecal incontinence.
Dr Carlos Belmonte-Montes, of the Hospital Central Militar, Mexico City, said on behalf of the group, "Anal sphincter injuries, many of them undiagnosed at the time of delivery, are common in primiparous females after vaginal delivery. This is especially the case if vacuum or forceps are used.
"These injuries cause fecal incontinence in a significant proportion of the patients."
"Patients undergoing vaginal delivery should be aware of the risks of anal sphincter injury," he concluded.