Sphincter rupture and anal incontinence after first vaginal delivery

Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta-analysis

OBJECTIVES

The primary objective was to perform a systematic review of predictive factors for obstetric anal sphincter injury (OASI) occurrence at first vaginal delivery, with the diagnosis made by ultrasound (US-OASI). The secondary objective was to report on incidence rates of sonographic anal sphincter (AS) trauma, including trauma that was not clinically reported at childbirth, among the studies providing data for our primary objective.

METHODS

We conducted a systematic search of MEDLINE, EMBASE, Web of Science, CINAHL, The Cochrane Library and ClinicalTrials.gov databases. Both observational cohort studies and interventional trials were eligible for inclusion. Study eligibility was assessed independently by two authors. Random-effects meta-analyses were performed to pool effect estimates from studies reporting on similar predictive factors. Summary odds ratio (OR) or mean difference (MD) is reported with 95% CI. Heterogeneity was assessed using the I2 statistic. Methodological quality was assessed using the Quality in Prognosis Studies tool.

RESULTS

A total of 2805 records were screened and 21 met the inclusion criteria (16 prospective cohort studies, three retrospective cohort studies and two interventional non-randomized trials). Increasing gestational age at delivery (MD, 0.34 (95% CI, 0.04-0.64) weeks), shorter antepartum perineal body length (MD, -0.60 (95% CI, -1.09 to -0.11) cm), labor augmentation (OR, 1.81 (95% CI, 1.21-2.71)), instrumental delivery (OR, 2.13 (95% CI, 1.13-4.01)), in particular forceps extraction (OR, 3.56 (95% CI, 1.31-9.67)), shoulder dystocia (OR, 12.07 (95% CI, 1.06-137.60)), episiotomy use (OR, 1.85 (95% CI, 1.11-3.06)) and shorter episiotomy length (MD, -0.40 (95% CI, -0.75 to -0.05) cm) were associated with US-OASI. When pooling incidence rates, 26% (95% CI, 20-32%) of women who had a first vaginal delivery had US-OASI (20 studies; I2  = 88%). In studies reporting on both clinical and US-OASI rates, 20% (95% CI, 14-28%) of women had AS trauma on ultrasound that was not reported clinically at childbirth (16 studies; I2  = 90%). No differences were found in maternal age, body mass index, weight, subpubic arch angle, induction of labor, epidural analgesia, episiotomy angle, duration of first/second/active-second stages of labor, vacuum extraction, neonatal birth weight or head circumference between cases with and those without US-OASI. Antenatal perineal massage and use of an intrapartum pelvic floor muscle dilator did not affect the odds of US-OASI. Most (81%) studies were judged to be at high risk of bias in at least one domain and only four (19%) studies had an overall low risk of bias.

CONCLUSION

Given the ultrasound evidence of structural damage to the AS in 26% of women following a first vaginal delivery, clinicians should have a low threshold of suspicion for the condition. This systematic review identified several predictive factors for this. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Short and long term results of anatomical reconstruction of perineal body and sphincter complex in obstetric anal sphincter injuries

OBJECTIVES

The effective way to reduce the risk of fecal incontinence (FI) in primary repaired obstetric anal sphincter injuries (OASIS) patients is to accurately detect the injury and provide complete anatomical reconstruction. The aim of the study was to evaluate the short-term and long-term results of OASIS cases that were diagnosed by an experienced surgical team and whose perineal body and anal sphincters were reconstructed separately.

MATERIAL AND METHODS

Sixteen patients that required consultations due to anal sphincter damage during vaginal delivery and underwent anatomical reconstruction due to Grade 3c and Grade 4 sphincter damage between 2007 and 2019 were included in the study. These cases were divided into three groups [Group 1 (≤12 months), Group 2 (12-60 months), Group 3 (≥60 months)] according to the time elapsed until anal manometry, and incontinence questionnaires were conducted in the postoperative period. Recto-anal inhibitory reflex (RAIR), mean resting (IB) and squeezing (SB) pressures were measured by anal manometry. Anal incontinence (AI) and FI rates were determined by questionnaires. Anal sphincter damage repair techniques (overlapping, end-to-end) were determined. These parameters were compared between the three groups.

RESULTS

Mean age of the patients was 27.5 (16-35) years. Six (37.5%) patients had Grade 3c, while 10 (62.5%) had Grade 4 injury. The overall mean RP and SP were 35 (26-56) mmHg and 67 (31-100) mmHg, respectively. Mean RP and SP were 46/67 mmHg, 33.5/75.5 mmHg, and 37.5/70.5 mmHg in Groups 1, 2, and 3 respectively. There was no difference between the three groups in terms of mean RP and SP (p= 0.691, p= 0.673). The rate of AI and FI in all patients were 18.75% and 12.5%, respectively while the rate of severe AI incontinence was 6%. Severe AI was observed in 1 (16.7%) case in Group 1, mild AI was observed in 1 (25%) case in group 2, and in 1 (16.7%) case in Group 3. RAIR was positive in all patients. In Group 1, 5 (83.3%) patients underwent overlapping repair, and in Group 3, 6 (100%) patients underwent end-to-end repair. This difference was statistically significant (p= 0.011).

CONCLUSION

In vaginal births, evaluation of anal sphincter damage, determination of perineal body structures and anal sphincters separately and performing anatomical reconstruction when needed significantly reduce the rate of FI in the short and long term.

Obstetric risk factors for anorectal dysfunction after delivery: a systematic review and meta-analysis

INTRODUCTION AND HYPOTHESIS

Pregnancy and childbirth are considered risk factors for pelvic floor dysfunction, including anorectal dysfunction. We aimed to assess the effect of obstetric events on anal incontinence and constipation after delivery.

METHODS

We systematically reviewed the literature by searching MEDLINE, Embase and CENTRAL. We included studies in women after childbirth examining the association between obstetric events and anorectal dysfunction assessed through validated questionnaires. We selected eligible studies and clustered the data according to the type of dysfunction, obstetric event and interval from delivery. We assessed risk of bias using the Newcastle Ottawa Scale and we performed a random-effects meta-analysis and reported the results as odds ratios (ORs) with their 95% confidence intervals. Heterogeneity across studies was assessed using I² statistics.

RESULTS

Anal sphincter injury (OR: 2.44 [1.92-3.09]) and operative delivery were risk factors for anal incontinence (forceps-OR :1.35 [1.12-1.63]; vacuum-OR: 1.17 [1.04-1.31]). Spontaneous vaginal delivery increased the risk of anal incontinence compared with caesarean section (OR: 1.27 [1.07-1.50]). Maternal obesity (OR:1.48 [1.28-1.72]) and advanced maternal age (OR: 1.56 [1.30-1.88]) were risk factors for anal incontinence. The evidence on incontinence is of low certainty owing to the observational nature of the studies. No evidence was retrieved regarding constipation after delivery because of a lack of standardised validated assessment tools.

CONCLUSIONS

Besides anal sphincter injury, forceps delivery, maternal obesity and advanced age were associated with higher odds of anal incontinence, whereas caesarean section is protective. We could not identify obstetric risk factors for postpartum constipation, as few prospective studies addressed this question and none used a standardised validated questionnaire.

Risk of obstetric anal sphincter injuries (OASIS) and anal incontinence: A meta-analysis

BACKGROUND

Obstetric anal sphincter injuries (OASIS) are the commonest cause of anal incontinence in women of reproductive age. We determined the risk of anal sphincter defects diagnosed by ultrasound, and the risk of anal incontinence in (i) all women who deliver vaginally, (ii) in women without clinical suspicion of OASIS, and (iii) after primary repair of sphincter injury, by systematic review.

METHODS

We searched major databases until June 2018, without language restrictions. Random effects meta-analysis was used to obtain pooled estimates of ultrasound diagnosed OASIS and risk of anal incontinence symptoms at various time points after delivery, and of persistent sphincter defects after primary repair. We reported the association between ultrasound diagnosed OASIS and anal incontinence symptoms using relative risk (RR) with 95 % CI.

RESULTS

We included 103 studies involving 16,110 women. Of all women who delivered vaginally, OASIS were diagnosed on ultrasound in 26 % (95 %CI, 21-30, I² = 91 %), and 19 % experienced anal incontinence (95 %CI, 14-25, I² = 92 %). In women without clinical suspicion of OASIS (n = 3688), sphincter defects were observed in 13 % (10-17, I² = 89 %) and anal incontinence experienced by 14 % (95 % CI: 6-24, I² = 95 %). Following primary repair of OASIS, 55 % (46-63, I² = 98 %) of 7549 women had persistent sphincter defect with 38 % experiencing anal incontinence (33-43, I² = 92 %). There was a significant association between ultrasound diagnosed OASIS and anal incontinence (RR 3.74, 2.17-6.45, I² = 98 %).

INTERPRETATION

Women and clinicians should be aware of the high risk for sphincter defects following vaginal delivery even when clinically unsuspected. This underlines the need of careful and systematic perineal assessment after birth to mitigate the risk of missing OASIS. We also noted a high rate of persistent defects and symptoms following primary repair of OASIS. This dictates the need for provision of robust training for clinicians to achieve proficiency and sustain competency in repairing OASIS.

Inflammatory bowel disease position statement of the Italian Society of Colorectal Surgery (SICCR): ulcerative colitis

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a Position Statement of Italian colorectal surgeons to address the surgical aspects of ulcerative colitis management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of ulcerative colitis. The committee was able to identify some points of major disagreement and suggested strategies to improve the quality of available data and acceptance of guidelines.

Obstetric trauma, pelvic floor injury and fecal incontinence: a population-based case-control study

OBJECTIVES

Current concepts based on referral center data suggest that pelvic floor injury from obstetric trauma is a major risk factor for fecal incontinence (FI) in women. In contrast, a majority of community women only develop FI decades after vaginal delivery, and obstetric events are not independent risk factors for FI. However, obstetric events are imperfect surrogates for anal and pelvic floor injury, which is often clinically occult. Hence, the objectives of this study were to evaluate the relationship between prior obstetric events, pelvic floor injury, and FI among community women.

METHODS

In this nested case-control study of 68 women with FI (cases; mean age 57 years) and 68 age-matched controls from a population-based cohort in Olmsted County, MN, pelvic floor anatomy and motion during voluntary contraction and defecation were assessed by magnetic resonance imaging. Obstetric events and bowel habits were recorded.

RESULTS

By multivariable analysis, internal sphincter injury (cases-28%, controls-6%; odds ratio (OR): 8.8; 95% confidence interval (CI): 2.3-34) and reduced perineal descent during defecation (cases-2.6 ± 0.2 cm, controls-3.1 ± 0.2 cm; OR: 1.7; 95% CI: 1.2-2.4) increased FI risk, but external sphincter injury (cases-25%, controls-4%; P<0.005) was not independently predictive. Puborectalis injury was associated (P<0.05) with impaired anorectal motion during squeeze, but was not independently associated with FI. Grades 3-4 episiotomy (OR: 3.9; 95% CI: 1.4-11) but not other obstetric events increased the risk for pelvic floor injury. Heavy smoking (≥ 20 pack-years) was associated (P=0.052) with external sphincter atrophy.

CONCLUSIONS

State-of-the-art imaging techniques reveal pelvic floor injury or abnormal anorectal motion in a minority of community women with FI. Internal sphincter injury and reduced perineal descent during defecation are independent risk factors for FI. In addition to grades 3-4 episiotomy, smoking may be a potentially preventable, risk factor for pelvic floor injury.

High episiotomy rate protects from obstetric anal sphincter ruptures: A birth register-study on delivery intervention policies in Finland

Aim: To assess the impact of hospital episiotomy policy on obstetric and anal sphincter rupture (OASR, n = 2448) rates and risks among singleton vaginal deliveries in Finland between 1997 and 2007. Methods: An observational, retrospective, population-based register study. All 424,297 women in hospitals with more than 1000 deliveries annually, were divided into three groups based on the episiotomy rate quartiles for 11 years and separated on the basis of whether the women were primiparous or multiparous. The lowest and the highest quartiles were compared against the hospitals with intermediate episiotomy rates, comprising the two quartiles around the median. Stepwise logistic regression analysis was used to adjust significant risk factors. Results: The annual range of episiotomy varied from 11 to 94% in primiparous women, and from 1 to 46% in multiparous women. After adjustment the risk of OASR appears to be 39% lower (OR 0.61, 95% CI 0.52—0.90) in primiparous and 45% lower (OR 0.55, 95% CI 0.42—0.72) in multiparous women delivered in the highest quartile hospitals. At an individual level, episiotomy was a protective factor (OR 0.82, 95% CI 0.75—0.91) in primiparous women, but increased the risk by 2.36-fold in multiparous women (OR 2.36, 95% CI 1.86—2.84). Conclusions: The results suggest that high episiotomy rate provided protection from OASR among both groups of women. Among the multiparous women, the 2.4-fold risk of OASR related to episiotomy at an individual level might be explained by confounding by indication, since episiotomy was performed more often to women at a high risk of OASR.

Cesarean delivery for the prevention of anal incontinence

BACKGROUND

Caesarean delivery (CD) is a common form of delivery of a baby, rising in frequency. One reason for its performance is to preserve maternal pelvic floor function, part of which is anal continence.

OBJECTIVES

To assess the ability of CD in comparison to vaginal delivery (VD) to preserve anal continence in a systematic review

SEARCH STRATEGY

Search terms include: "Caesarean section, Cesarean delivery, vaginal delivery, incontinence and randomised". PubMed, EMBASE and the Cochrane Central Register of Controlled Trials (Central) were searched from their inception through July, 2009.

SELECTION CRITERIA

Both randomised and non-randomised studies that allowed comparisons of post partum anal continence (both fecal and flatus) in women who had had babies delivered by either CD or VD were included.

DATA COLLECTION AND ANALYSIS

Mode of delivery, and when possible mode of all previous deliveries prior to the index pregnancy were extracted, as well as assessment of continence post partum of both faeces and flatus. In Non-RCTs, available adjusted odds ratios were the primary end point sought. Incontinence of flatus is reported as a separate outcome. Summary odds ratios are not presented as no study was analysed as a randomised controlled trial. Numbers needed to treat (NNT) are presented, that is, the number of CDs needed to be performed to prevent a single case of fecal or flatus incontinence, for each individual study. Quality criteria were developed, selecting studies that allowed maternal age adjustment, studies that allowed a sufficient time after the birth of the baby for continence assessment and studies in which mode of delivery of prior pregnancies was known. Subgroup analyses were done selecting studies meeting all quality criteria and in comparisons of elective versus emergency CD, elective CD versus VD and nulliparous women versus those delivered by VD or CD, in each case again, not calculating a summary risk statistic.

MAIN RESULTS

Twentyone reports have been found eligible for inclusion in the review, encompassing 31,698 women having had 6,028 CDs and 25,170 VDs as the index event prior to anal continence assessment . Only one report randomised women (with breech presentation) to CD or VD, but because of extensive crossing over, 52.1%, after randomisation, it was analysed along with the other 20 studies as treated, i.e. as a non-randomised trial. Only one of these reports demonstrated a significant benefit of CD in the preservation of anal continence, a report in which incontinence incidence was extremely high, 39% in CD and 48% in VD, questioning, relative to other reports, the timing and nature of continence assessment. The greater the quality of the report, the closer its Odds ratio approached 1.0. There was no difference in continence preservation in women have emergency versus elective CD.

AUTHORS' CONCLUSIONS

Without demonstrable benefit, preservation of anal continence should not be used as a criterion for choosing elective primary CD. The strength of this conclusion would be greatly strengthened if there were studies that randomised women with average risk pregnancies to CD versus VD.

Onset and risk factors for fecal incontinence in a US community

OBJECTIVES

The natural history of fecal incontinence (FI) in community subjects is uncertain and the onset rate is unknown. The aim of the study is to estimate the prevalence, new-onset rate, and risk factors for FI in community subjects.

METHODS

A random sample of 2,400 community subjects aged > or =50 years was surveyed in 1993, using a validated questionnaire. Responders were recontacted in 2003. FI was defined as self-reported problems with leakage of stool. Onset rate was calculated as the proportion of subjects without FI who became new cases. Logistic regression models were constructed to identify predictive factors for developing FI and changes in bowel habit associated with the onset of FI.

RESULTS

Overall, 1,540 (64%) subjects responded to the initial survey, and 674 (44%) of them responded to the second survey a median of 9 (8.8-9.5) years later. The prevalence of FI in the first survey was 15.3% (13.4-17.3%). In the second survey, 37 reported incident FI; thus, the onset rate of FI was 7.0% (5.0-9.6) per 10 years. Predictive factors at baseline for the onset of FI were self-reported diarrhea (odds ratio (OR)=3.8 (1.5, 9.4)), incomplete evacuation (OR=3.4 (1.2, 9.8)), and pelvic radiation (OR=5.1 (1.01, 25.9)). Development of urgency was the primary predictor among the set of predictors reflecting changes in bowel symptoms that were associated with the onset of FI (OR=24.9 (10.6, 58.4)).

CONCLUSIONS

The onset rate of FI is approximately 7% per 10 years in community subjects aged > or =50 years. Prevention may be possible if bowel habit is appropriately managed in high-risk individuals.

Anal resting pressures at manometry correlate with the Fecal Incontinence Severity Index and with presence of sphincter defects on ultrasound

INTRODUCTION

We describe the relationship between anorectal manometry, fecal incontinence severity, and findings at endoanal ultrasound.

METHODS

A total of 351 women completed the Fecal Incontinence Severity Index, underwent anorectal manometry, and endoanal ultrasound. Severity index and manometry pressures in 203 women with intact sphincters on ultrasound were compared with pressures in 148 women with sphincter defects. Relationships between resting and squeeze pressures, severity index, and size of sphincter defects were evaluated.

RESULTS

Mean severity index in patients with and without sphincter defect was 35.7 vs. 36.7 (not significant). Worsening index correlated with worsening mean and maximum resting pressure (P < 0.0001). Differences were observed in mean and maximum resting pressure between the patients with and without sphincter defects (26.6 vs. 37.2, P < 0.0001; 39.4 vs. 51.7, P < 0.001). Resting pressures correlated with the sizes of defect (P < 0.0001).

CONCLUSIONS

Patients with and without sphincter defects had similar severity scores, but patients with defects had a significant decrease in resting pressures. Patients with larger sphincter defects had lower severity scores and resting pressures. Until a manometry cutoff can be set to discriminate between absence and presence of defects, both manometry and ultrasound should be offered to patients with history of anal trauma.

Obstetric anal sphincter injury: incidence, risk factors, and management

BACKGROUND AND AIMS

Obstetric sphincter damage is the most common cause of fecal incontinence in women. This review aimed to survey the literature, and reach a consensus, on its incidence, risk factors, and management.

METHOD

This systematic review identified relevant studies from the following sources: Medline, Cochrane database, cross referencing from identified articles, conference abstracts and proceedings, and guidelines published by the National Institute of Clinical Excellence (United Kingdom), Royal College of Obstetricians and Gynaecologists (United Kingdom), and American College of Obstetricians and Gynecologists.

RESULTS

A total of 451 articles and abstracts were reviewed. There was a wide variation in the reported incidence of anal sphincter muscle injury from childbirth, with the true incidence likely to be approximately 11% of postpartum women. Risk factors for injury included instrumental delivery, prolonged second stage of labor, birth weight greater than 4 kg, fetal occipitoposterior presentation, and episiotomy. First vaginal delivery, induction of labor, epidural anesthesia, early pushing, and active restraint of the fetal head during delivery may be associated with an increased risk of sphincter trauma. The majority of sphincter tears can be identified clinically by a suitably trained clinician. In those with recognized tears at the time of delivery repair should be performed using long-term absorbable sutures. Patients presenting later with fecal incontinence may be managed successfully using antidiarrheal drugs and biofeedback. In those who fail conservative treatment, and who have a substantial sphincter disruption, elective repair may be attempted. The results of primary and elective repair may deteriorate with time. Sacral nerve stimulation may be an appropriate alternative treatment modality.

CONCLUSIONS

Obstetric anal sphincter damage, and related fecal incontinence, are common. Risk factors for such trauma are well recognized, and should allow for reduction of injury by proactive management. Improved classification, recognition, and follow-up of at-risk patients should facilitate improved outcome. Further studies are required to determine optimal long-term management.

Delivery method, anal sphincter tears and fecal incontinence: new information on a persistent problem

PURPOSE OF REVIEW

To review the risk factors for anal sphincter tears during vaginal delivery and their association with fecal incontinence symptoms.

RECENT FINDINGS

Recent evidence links sphincter tears with fecal incontinence, which has a significant negative impact on quality of life. The Childbirth and Pelvic Symptoms cohort study reported that the incidence and severity of fecal incontinence was increased in primiparous women experiencing a sphincter tear. Risk factors for tear included forceps, occiput posterior, vacuum delivery, prolonged second stage of labor and epidural. Using cesarean delivery to prevent fecal incontinence has not been justified, but the confluence of these risk factors in the context of labor management may be important in deciding on earlier intervention with cesarean delivery. Internal anal sphincter defects impact fecal incontinence, highlighting the identification and repair of the internal anal sphincter for future research and clinical applications. Routine episiotomy (or instrumentation) is not warranted, and there is no clear advantage to mediolateral episiotomy or overlapping sphincter repair. Postpartum ultrasound of the sphincter complex may have an emerging role.

SUMMARY

The modifiable risk factors of routine episotomy and instrumented delivery are associated with sphincter tear; definitive recommendations for labor management remain unclear in preventing fecal incontinence.

Female fertility and childbirth after ileal pouch-anal anastomosis for ulcerative colitis

BACKGROUND

The aim of this study was to calculate the probability of becoming pregnant after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis, and to evaluate complications during pregnancy and childbirth.

METHODS

A questionnaire was posted to 160 women with an IPAA and to 160 controls. The probability of becoming pregnant after IPAA was calculated by the Kaplan-Meier method.

RESULTS

Of 54 women who had undergone IPAA surgery, 36 (67 per cent) succeeded in becoming pregnant naturally, compared with 49 (82 per cent) of 60 controls. The probability of pregnancy after 2 years of trying was 56 per cent in the IPAA group and 91 per cent in the control group (P < 0.001). Women in the IPAA group needed infertility investigations more often (24 versus 10 per cent; P = 0.044). In all, 39 (72 per cent) women in the IPAA group and 53 (88 per cent) in the control group bore a child. Twenty-one of 39 women in the IPAA group and 13 of 53 in the control group had a caesarean section (P = 0.005). Anal incontinence after delivery occurred more often in the control group.

CONCLUSION

Women with an IPAA mostly suffer a reduction in the probability of conception rather than complete infertility. Because complications during pregnancy and delivery were rare, caesarean section should be based mainly on obstetric indications.

Endoanal ultrasound findings and fecal incontinence symptoms in women with and without recognized anal sphincter tears

OBJECTIVE

To estimate whether endoanal ultrasound findings are more prevalent in primiparous women with a history of anal sphincter tear than in women without this history and whether the findings are associated with fecal incontinence symptoms.

METHODS

A total of 251 primiparous women at seven clinical sites underwent standardized ultrasound assessment of the internal and external anal sphincter 6-12 months after delivery. Participants were women in the three cohorts of the Childbirth and Pelvic Symptoms Study: 1) women with clinically evident third- or fourth-degree tear at vaginal delivery (n=106); 2) no tear at vaginal delivery (n=106); and 3) cesarean delivery without labor (n=39). Women completed the Fecal Incontinence Severity Index to assess fecal incontinence symptoms.

RESULTS

Thirty-five percent of the sphincter tear group exhibited internal sphincter gaps compared with 3% of vaginal controls (odds ratio [OR] 18.4, 95% confidence interval [CI] 5.5-62.1) and 10% of cesarean controls. External sphincter gaps were identified in 51% of the tear group compared with 31% of vaginal controls (OR 2.3, 95% CI 1.3-4.0) and 28% of cesarean controls. In the tear group, fecal incontinence severity was greater in those with internal sphincter gaps compared with those with no internal sphincter gaps (Fecal Incontinence Severity Index score 6.6+/-8.3 compared with 3.3+/-6.1, P=.02), as well as in those with external sphincter gaps (6.1+/-8.4 compared with 2.7+/-5.0, P=.01), and greatest in those with both internal and external sphincter gaps compared with at least one gap not present (7.2+/-8.1 compared with 3.4+/-6.4, P=.003).

CONCLUSION

Anal sphincter gaps detected by ultrasonography are prevalent in postpartum primiparous women with a history of sphincter tear and are associated with fecal incontinence severity.

LEVEL OF EVIDENCE

II-2.

A systematic review of the efficacy of cesarean section in the preservation of anal continence

PURPOSE

Elective primary cesarean section is performed largely to avoid maternal pelvic trauma that may result in anal incontinence, although its efficacy in this regard has not been thoroughly assessed. We perform a systematic review of published reports that compare anal incontinence risk by mode of delivery.

METHODS

PubMed was searched from 1966 through August 2005. Authors were contacted for missing data or analyses. Both randomized and nonrandomized reports were included. Eligible studies included females having vaginal delivery or cesarean section, fecal and/or flatal incontinence was reported as an outcome, and risk was calculable from the reported data. Crude data were extracted from the reports, as well as reported odds ratios and confidence intervals. In the nonrandomized studies, adjusted odds ratios also were extracted and additional data obtained from authors to adjust risks for age and parity if not originally done. Sensitivity analyses were performed using quality indicators: age and parity adjustment, time to continence assessment, and mode of previous delivery.

RESULTS

Fifteen studies were found eligible, encompassing 3,010 cesarean sections and 11,440 vaginal deliveries. The summary relative risk for fecal incontinence was 0.91 (95 percent confidence interval, 0.74-1.14). For flatus the relative risk was 0.98 (range, 0.86-1.13). The number needed to treat by cesarean section was 167 to prevent a single case of fecal incontinence. Five studies were judged to be of high quality. In these studies, the summary relative risk was 0.94 (range, 0.72-1.22) and number needed to treat was 198.

CONCLUSIONS

The best evidence to assess the efficacy of cesarean section in the prevention of anal incontinence would be in randomized trials of average-risk pregnancies with few crossovers. In the absence of such trials and based on this review, cesarean section does not prevent anal incontinence. This implies that incontinence associated with delivery may be more likely incontinence caused by pregnancy.