Evaluating the Pelvic Floor in Obstetric Patients
Authors: Small K A , Wynne J M 
Published: February 2008

EDITORIAL COMMENT: This paper presents important information that will be new to many readers about the possibility of pelvic floor denervation occurring in association with pregnancy or delivery. There is some evidence that the condition can occur irrespective of the mode of delivery and antenatal exercises may be of relevance in avoidance of the problem. The important point is that we realize the condition does occur and that it may be influenced by antenatal preparation or the mechanics of delivery in which case we need to know whether timely episiotomy and/or forceps delivery without undue pushing in the second stage is of possible preventative value. There is no doubt that faecal incontinence is a fairly common temporary problem after vaginal delivery especially when an episiotomy has been necessary; although the condition usually resolves, it is a cause of considerable embarrassment — the patient often does not volunteer the symptom at the time of a postnatal visit unless asked. Moreover there are some patients in whom the problem is persistent and occasionally the condition can cause confusion with incontinence thought to be due to an improperly sutured third degree tear. The degree of faecal incontinence following external sphincter repair depends on the extent of injury to the pudenda! nerve. More long‐term follow‐up information is required about this entity and whether persistent problems are associated with particular delivery techniques which may indicate the possibility of prevention. It is also interesting to note that there is evidence that constipation and defaecation straining can damage the nerve supply of the puborectalis and external and sphincter muscles due to perineal descent, resulting in anorectal incontinence1B.

1A. Laurberg S, Swash M. Henry MM. Delayed external sphincter repair for obstetric tear. Br J Surg 1988; 75: 786–788.

1B. Snooks SJ, Barnes PRH, Swash M, Henry MM. Damage to the innervation of the pelvic floor musculature in chronic constipation. Gastroent 1985; 89: 977–981.

Summary: Up to 40% of vaginal deliveries lead to pelvic floor denervation. This has been linked causally with the later occurrence of urinary incontinence, faecal incontinence and vaginal prolapse. Pelvic floor position, anal sphincter pressures and anal electrosensitivity were evaluated in 72 volunteers as simple screening tests for detecting patients who might benefit from neurological assessment. A lower perineum and reduced voluntary sphincter pressures were found antenatally in parous women when compared with nulliparas. The tests were repeated postnatally 24 to 72 hours after delivery. When compared with antenatal readings, the perineum was lower and sphincter pressures were reduced in subjects delivered vaginally. Forty one subjects were reexamined after 6–8 weeks and partial recovery was found. Anal squeeze pressures and pelvic floor position when straining were the results most consistently changed. On the basis of this study it is suggested that 28% of multiparas seen anrenatally and between 25% to 30% of all women who deliver vaginally may be eligible for more detailed neurological study.