The effect of a normal vaginal delivery on anal function

Cell-based secondary prevention of childbirth-induced pelvic floor trauma

With advancing population age, pelvic-floor dysfunction (PFD) will affect an increasing number of women. Many of these women wish to maintain active lifestyles, indicating an urgent need for effective strategies to treat or, preferably, prevent the occurrence of PFD. Childbirth and pregnancy have both long been recognized as crucial contributing factors in the pathophysiology of PFD. Vaginal delivery of a child is a serious traumatic event, causing anatomical and functional changes in the pelvic floor. Similar changes to those experienced during childbirth can be found in symptomatic women, often many years after delivery. Thus, women with such PFD symptoms might have incompletely recovered from the trauma caused by vaginal delivery. This hypothesis creates the possibility that preventive measures can be initiated around the time of delivery. Secondary prevention has been shown to be beneficial in patients with many other chronic conditions. The current general consensus is that clinicians should aim to minimize the extent of damage during delivery, and aim to optimize healing processes after delivery, therefore preventing later dysfunction. A substantial amount of research investigating the potential of stem-cell injections as a therapeutic strategy for achieving this purpose is currently ongoing. Data from small animal models have demonstrated positive effects of mesenchymal stem-cell injections on the healing process following simulated vaginal birth injury.

The immediate effect of vaginal and caesarean delivery on anal sphincter measurements

Objective

This study evaluated the effects of vaginal and caesarean delivery on internal and external anal sphincter muscle thickness using translabial ultrasonography (TL-US).

Methods

This prospective cohort study enrolled nulliparous women who either had vaginal or caesarean deliveries. The thickness of the hypoechoic internal anal sphincter (IAS) and hyperechoic external anal sphincter (EAS) at the 12, 3, 6, and 9 o’clock positions at the distal level were measured before delivery and within 24–48 h after delivery.

Results

A total 105 consecutive women were enrolled in the study: 60 in the vaginal delivery group and 45 in the caesarean delivery group. The IAS muscle thickness at the 12 o’clock position in the vaginal delivery group was significantly thicker before compared with after delivery (mean ± SD: 2.31 ± 0.74 mm versus 1.81 ± 0.64 mm, respectively). The EAS muscle thickness at the 12 o’clock position in the vaginal delivery group was significantly thicker before compared with after delivery (mean ± SD: 2.42 ± 0.64 mm versus 1.97 ± 0.85, respectively).

Conclusions

There was significant muscle thinning of both the IAS and EAS at the 12 o’clock position after vaginal delivery, but not after caesarean delivery.

Pregnancy and postpartum bowel changes: constipation and fecal incontinence

Pregnancy and the postpartum period are often associated with many gastrointestinal complaints, including nausea, vomiting, and heartburn; however, the most troublesome complaints in some women are defecatory disorders such as constipation and fecal incontinence, especially postpartum. These disorders are often multifactorial in etiology, and many studies have looked to see what risk factors lead to these complications. This review discusses the current knowledge of pelvic floor and anorectal physiology, especially during pregnancy, and reviews the current literature on causes and treatments of postpartum bowel symptoms of constipation and fecal incontinence.

Manometric evaluation of anal sphincter function after vaginal and cesarean delivery

OBJECTIVE

To compare anal sphincter function following spontaneous vaginal delivery and cesarean delivery, and assess the association of perineal length and sphincter injury with each delivery mode.

METHOD

Perineal length was measured and anal manometric measurements were performed in 120 primigravidas before and after delivery.

RESULTS

Mean values for maximum anal resting and squeeze pressures were significantly lower after delivery irrespective of the mode of delivery, but there was a positive correlation between postpartum maximum anal resting pressure and perineal length (r=0.24, P<0.01).

CONCLUSION

Anal sphincter function was disturbed after both vaginal and cesarean delivery, a finding weakened by the fact that almost half of the cesareans were performed for cephalopelvic disproportion identified during labor.

Does the mode of delivery predispose women to anal incontinence in the first year postpartum? A comparative systematic review

OBJECTIVES

To assess if mode of delivery is associated with increased symptoms of anal incontinence following childbirth.

DESIGN

Systematic review of all relevant studies in English.

DATA SOURCES

Medline, Embase, Cochrane Library, bibliographies of retrieved primary articles and consultation with experts.

STUDY SELECTION AND DATA EXTRACTION

Data were extracted on study characteristics, quality and results. Exposure to risk factors was compared between women with and without anal incontinence. Categorical data in 2 x 2 contingency tables were used to generate odds ratios.

RESULTS

Eighteen studies met the inclusion criteria with 12,237 participants. Women having any type of vaginal delivery compared with a caesarean section have an increased risk of developing symptoms of solid, liquid or flatus anal incontinence. The risk varies with the mode of delivery ranging from a doubled risk with a forceps delivery (OR 2.01, 95% CI 1.47-2.74, P < 0.0001) to a third increased risk for a spontaneous vaginal delivery (OR 1.32, 95% CI 1.04-1.68, P = 0.02). Instrumental deliveries also resulted in more symptoms of anal incontinence when compared with spontaneous vaginal delivery (OR 1.47, 95% CI 1.22-1.78). This was statistically significant for forceps deliveries alone (OR 1.5, 95% CI 1.19-1.89, P = 0.0006) but not for ventouse deliveries (OR 1.31, 95% CI 0.97-1.77, P = 0.08). When symptoms of solid and liquid anal incontinence alone were assessed, these trends persisted but were no longer statistically significant.

CONCLUSION

Symptoms of anal incontinence in the first year postpartum are associated with mode of delivery.

Impact of pregnancy and parturition on the anal sphincters and pelvic floor

Incontinence and defecatory difficulties are commonly reported among women and are often ascribed to traumas sustained during childbirth. Specifically, injuries to the anal sphincters (tears) and conformational changes in the various structures that comprise the pelvic floor (prolapse and perineal descent) have been considered as important contributors to the development of anal incontinence, or difficult defaecation (straining, incomplete evacuation), in later life. An understanding of both the effects of pregnancy and parturition on these structures and the natural history of any traumas sustained are, therefore, of key importance. Unfortunately, the literature on these issues, though vast, is far from complete. While it is evident that pregnancy, per se, imposes changes, primarily through hormonal influences, on colonic, ano-rectal and pelvic floor physiology, the long-term impact of such effects is far from clear. Risk factors for the occurrence of significant, though often occult, anal sphincter injuries during birth have been identified and the role of these tears in the etiology of post-partum incontinence has been well delineated. In contrast, the contribution of such intra-partum events to the later onset of incontinence is far from clear and may well have been over-estimated.

Factors associated with postpartum urinary/anal incontinence in primiparous women in Quebec

OBJECTIVE

To identify the factors associated with urinary incontinence (UI), anal incontinence (AI), and combined UI and AI (UI/AI) in primiparous women in Quebec at six months postpartum.

METHODS

A questionnaire was mailed to 2492 primiparous women at six months postpartum to collect data on incontinence status, sociodemographic characteristics, elimination habits, lifestyle, and severity index scales. Obstetric characteristics were obtained via Quebec's Med-Echo databank. Pearson chi-square, t test, analysis of variance, univariate regression, and stepwise modelling techniques were used for data analysis.

RESULTS

The prevalence of UI in responders was 29.6%, of AI, 20.6%, and of combined UI/AI, 10.4%. Significant adjusted odds ratios were (1) for UI, English spoken (2.04 [95% confidence intervals 1.13-3.69]) and shoulder dystocia (2.90 [1.09-7.69]); (2) for AI, age > 35 years (2.13 [1.12-4.03]), duration of second stage of labour (1.67 [1.11-2.51]), and third or fourth degree tears (4.00 [2.32-6.89]); and (3) for UI and AI, age (2.00 [1.04-3.83]), English spoken (2.55 [1.25-5.19]), shoulder dystocia (4.91 [1.76-13.71]), instrumental delivery (2.28 [1.30-3.99]), third or fourth degree tears (3.58 [1.95-6.57]), and episiotomy (2.24 [1.162-4.33]). Caesarean section was associated with less UI (0.45 [0.28-0.72]), and smoking was associated with less AI (0.38 [0.19-0.76]).

CONCLUSION

Combined UI/AI is associated with several obstetrical factors. The association of UI and AI is observed more frequently after complicated delivery (requiring the application of forceps) or involving perineal damage and episiotomy. As most of the identified factors are modifiable, a preventive treatment policy is advisable.

Diagnosis of anal sphincter tears to prevent fecal incontinence: a randomized controlled trial

OBJECTIVE

Maternal anal sphincter tears after vaginal delivery are frequently not diagnosed clinically and are associated with subsequent fecal incontinence. This study examined whether diagnosis of these tears by ultrasonography, followed by immediate surgical repair, reduces the occurrence of incontinence.

METHODS

We conducted a randomized trial involving 752 primiparous women without a clinically evident anal sphincter tear to evaluate the benefit of adding endoanal ultrasonography immediately after vaginal delivery to the standard clinical examination of the perineum. When a sphincter tear was diagnosed, the perineum was surgically explored and the sphincter sutured. The main outcome evaluated was fecal incontinence 3 months postpartum graded by the Wexner incontinence scale, which measures incontinence to flatus and liquid or solid stools, need to wear a pad, and lifestyle alterations.

RESULTS

Among women assessed by ultrasonography, 5.6% had a sphincter tear. Severe incontinence was reported 3 months after childbirth by 3.3% of women in the intervention group compared with 8.7% in the control group (risk difference -5.4%; 95% confidence interval -8.9 to -2.0; P = .002). The benefit of the intervention persisted 1 year after delivery, with 3.2% severe incontinence in the intervention group compared with 6.7% in the control group (risk difference -3.5%; 95% confidence interval -6.8% to -0.3%; P = .03). Ultrasonography needs to be performed in 29 women to prevent 1 case of severe fecal incontinence.

CONCLUSION

Ultrasound examination of the perineum after childbirth improves the diagnosis of anal sphincter tears, and their immediate repair decreases the risk of severe fecal incontinence.

LEVEL OF EVIDENCE

I.

Postpartum Urinary and Anal Incontinence: A Population-Based Study of Quality of Life of Primiparous Women in Quebec

OBJECTIVE

To describe the quality of life of primiparous women with urinary or anal incontinence.

METHODS

A questionnaire was mailed at six months postpartum to 2492 primiparous women living in Quebec. The prevalence of urinary incontinence was assessed at six months postpartum through the FPSUND severity score index; the prevalence of anal incontinence was assessed by the grading system of Vaizey et al.; the quality of life of women who developed incontinence was assessed using the Shumaker's I-QOL for urinary incontinence and Lowry's quality of life instrument for anal incontinence. Descriptive analysis, t-test, analysis of variance, and linear regression were used.

RESULTS

The prevalence of urinary incontinence was 29.6% and of anal incontinence was 20.6%. Quality of life was affected significantly by the presence of urinary incontinence or both forms of incontinence (P 0.001) and by the type of urinary incontinence (P < 0.001). Women with all types of anal incontinence had significantly lower quality of life scores for access to toilet (P < 0.001), lifestyle (P < 0.01), self-esteem (P = 0.037), and total score (P < 0.001). Quality of life correlated with the severity of both urinary incontinence and anal incontinence: the more severe the urinary or anal incontinence, the lower the quality of life score.

CONCLUSION

Women who have urinary or anal incontinence, or both, have significant reductions in indicators of quality of life. Research is needed to evaluate strategies for preventing and treating these problems.

Alteration of anal sphincter morphology following vaginal delivery revealed by multiplanar anal endosonography

OBJECTIVE

To assess morphologic change in the anal sphincters in the absence of endosonographic evidence of trauma after vaginal delivery.

DESIGN

Prospective observational study.

SETTING

District general hospital.

POPULATION

Consecutively booked nulliparous pregnant women attending antenatal clinic.

METHODS

All women were examined using three-dimensional anal endosonography, simple manometry and had questionnaire assessment of incontinence before and after delivery.

MAIN OUTCOME MEASURES

Components of the anal canal were measured in the axial, sagittal and coronal planes and paired pre- and post-delivery examinations were compared. Any changes were related to changes in continence and anal canal manometry.

RESULTS

Twenty-two women had a vaginal delivery and no endosonographic evidence of perineal trauma after delivery. After delivery, there was significant shortening of the length of the anterior external anal sphincter [EAS] (mean 21.7 vs 20.5 mm, P = 0.02) when measured in the sagittal plane, which increased in anterior angulation with respect to the axis of the anal canal (10 degrees vs 13.8 degrees, P = 0.03). In the axial plane, no change was seen in the thickness of any of the sphincter components after delivery. None of these morphologic changes correlated with changes in manometry or continence score.

CONCLUSIONS

Anal sphincter morphology changes after an otherwise atraumatic vaginal delivery. This change does not correlate with any functional symptoms.

Do occult anal sphincter injuries, vector volume manometry and delivery variables have any predictive value for bowel symptoms after first time vaginal delivery without third and fourth degree rupture? A prospective study

BACKGROUND

The aim of this study was to determine whether there exists a correlation between anal incontinence, occult sphincter injuries, anal manometry values, and delivery variables in primiparous women after first time vaginal delivery.

METHODS

Eighty-six primigravida women were recruited for this study. Transanal ultrasonography (TAUS) and vector volume manometry (VVM) was performed and bowel symptoms were recorded at 25 weeks of pregnancy and 5 months after labor. Incontinent women at 5 months after vaginal delivery were interviewed again at 12 months.

RESULTS

Nineteen women (25%) experienced flatus incontinence postpartum. After 12 months, only one-third of the women were still incontinent. Fourteen women (19%) showed abnormal TAUS of the anal sphincter. Of the delivery variables, only baby head circumference was significantly associated with flatus incontinence (p = 0.01). There was no correlation between flatus incontinence or delivery variables and anal sphincter injuries; VVM values were not associated with either anal sphincter injuries or flatus incontinence at 5 months, but VVM values were negatively associated with flatus incontinence at 12 months after labor.

CONCLUSIONS

At 5 months after labor, flatus incontinence is relatively common, and is not associated with reduced VVM values. Two-thirds of women recover from flatus incontinence during the first year. Women who had flatus incontinence persisting for a minimum of 1 year had reduced VVM values. Anal sphincter injuries as seen by TAUS are not associated with either VVM values or any delivery variable. Baby head circumference is the only delivery variable significantly associated with flatus incontinence.

Clinical neurophysiology and electrodiagnostic testing of the pelvic floor

This article summarizes our current understanding of the neuroanatomy and neurophysiology of the pelvic floor. The electrodiagnostic evaluation of the pelvic floor muscles and external anal sphincter, including pudendal nerve conduction studies, sacral reflexes, and needs EMG is presented. The discussion reviews the test methodology, the strengths and limitations of each test, and their clinical utility. The authors have tried to critically review the objective evidence to support the use of electrodiagnostic tests in the evaluation and management of pelvic floor disorders. The reader will have a better understanding of the rationale, methodology, clinical utility, and potential pitfalls for each of the commonly used neurophysiological tests of the pelvic floor.

Effect of delivery on anal sphincter morphology and function

PURPOSE

Anal sphincter injury is a serious complication of childbirth, which may result in persistent anal incontinence. Occult injuries, visualized with endoanal ultrasonography, have previously been reported in up to 35 percent of females in a British study. The aim of the present study was to study anal sphincter morphology and function before and after delivery in primiparous females in the United States.

METHODS

Thirty-eight primiparous patients (mean age, 31 years) were evaluated with endoanal ultrasonography, anal manometry, and pudendal nerve terminal motor latency during pregnancy and after delivery. Bowel function before and after delivery was recorded according to set questionnaires. Cesarean section was performed in three patients.

RESULTS

Clinical sphincter tears, requiring primary repair, occurred in 15 percent of the patients. After delivery endoanal ultrasonography revealed disruptions in the external anal sphincter in six patients, but no patient had disruption in the internal anal sphincter. One patient had slight scarring in the external sphincter. Of the seven patients with pathologic findings at endoanal ultrasonography, the left pudendal latency increased after delivery (P < 0.05), and manometric results were reduced. Three of these seven patients had a third-degree or fourth-degree tear during delivery. All investigations were normal in the three patients who underwent cesarean section.

CONCLUSIONS

The present study demonstrates a significant frequency of sphincter injuries (20 percent) after vaginal delivery. Obstetricians should be aware of this risk and explicitly inquire about incontinence symptoms at follow-up after delivery.