Anal incontinence after vaginal delivery: a five-year prospective cohort study

OBJECTIVE: The long-term prevalence of anal incontinence after vaginal delivery is unknown. The aim of the present study was to evaluate the prevalence of anal incontinence in primiparous women 5 years after their first delivery and to evaluate the influence of subsequent childbirth. METHODS: A total of 349 nulliparous women were prospectively followed up with questionnaires before pregnancy, at 5 and 9 months, and 5 years after delivery. A total of 242 women completed all questionnaires. Women with sphincter tear at their first delivery were compared with women without such injury. Risk factors for development of anal incontinence were also analyzed. RESULTS: Anal incontinence increased significantly during the study period. Among women with sphincter tears, 44% reported anal incontinence at 9 months and 53% at 5 years (P = .002). Twenty-five percent of women without a sphincter tear reported anal incontinence at 9 months and 32% had symptoms at 5 years (P < .001). Risk factors for anal incontinence at 5 years were age (odds ratio [OR] 1.1; 95% confidence interval [CI] 1.0-1.2), sphincter tear (OR 2.3; 95% CI 1.1-5.0), and subsequent childbirth (OR 2.4; 95% CI 1.1-5.6). As a predictor of anal incontinence at 5 years after the first delivery, anal incontinence at both 5 months (OR 3.8; 95% CI 2.0-7.3) and 9 months (OR 4.3; 95% CI 2.2-8.2) was identified. Among women with symptoms, the majority had infrequent incontinence to flatus, whereas fecal incontinence was rare. CONCLUSION: Anal incontinence among primiparous women increases over time and is affected by further childbirth. Anal incontinence at 9 months postpartum is an important predictor of persisting symptoms.     

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.     

Risk factors for anal sphincter tear during vaginal delivery

OBJECTIVE: To identify risk factors associated with anal sphincter tear during vaginal delivery and to identify opportunities for preventing this cause of fecal incontinence in young women. METHODS: We used baseline data from two groups of women who participated in the Childbirth and Pelvic Symptoms (CAPS) study: those women who delivered vaginally, either those with or those without a recognized anal sphincter tear. Univariable analyses of demographic and obstetric information identified factors associated with anal sphincter tear. We calculated odds ratios (ORs) for these factors alone and in combination, adjusted for maternal age, race, and gestational age. RESULTS: We included data from 797 primaparous women: 407 with a recognized anal sphincter tear and 390 without. Based on univariable analysis, a woman with a sphincter tear was more likely to be older, to be white, to have longer gestation or prolonged second stage of labor, to have a larger infant (birth weight/head circumference), or an infant who was in occiput posterior position, or to have an episiotomy or operative delivery. Logistic regression found forceps delivery (OR 13.6, 95% confidence interval [CI] 7.9-23.2) and episiotomy (OR 5.3, 95% CI 3.8-7.6) were strongly associated with a sphincter tear. The combination of forceps and episiotomy was markedly associated with sphincter tear (OR 25.3, 95% CI 10.2-62.6). The addition of epidural anesthesia to forceps and episiotomy increased the OR to 41.0 (95% CI 13.5-124.4). CONCLUSION: Our results highlight the existence of modifiable obstetric interventions that increase the risk of anal sphincter tear during vaginal delivery. Our results may be used by clinicians and women to help inform their decisions regarding obstetric interventions. LEVEL OF EVIDENCE: II.     

Anal sphincter tears at vaginal delivery: risk factors and clinical outcome of primary repair.

OBJECTIVE: To determine risk factors for obstetric anal sphincter tears and to evaluate symptomatic outcome of primary repair. METHODS: Obstetric-procedure, maternal, and fetal data were registered in 845 consecutive vaginally delivered women. Risk factors for anal sphincter tears were calculated by multiple logistic regression. All 808 Swedish-speaking women who delivered vaginally were included in a questionnaire study regarding anal incontinence in relation to the delivery. Questionnaires were distributed within the first few days postpartum, and at 5 and 9 months postpartum. RESULTS: Six percent of the women had a clinically detected sphincter tear at delivery. Sphincter tears were associated with nulliparity (odds ratio [OR] 9.8, 95% confidence interval [CI] 3.6, 26.2), postmaturity (OR 2.5, 95% CI 1.0, 6.2), fundal pressure (OR 4.6 95% CI 2.3, 7.9), midline episiotomy (OR 5.5 95% CI 1.4,18.7), and fetal weight in intervals of 250 g (OR 1.3 95% CI 1.1, 1.6). Fifty-four percent of women with repaired sphincter tears suffered from fecal or gas incontinence or both at 5 months and 41% at 9 months. Most of the symptoms were infrequent and mild. CONCLUSION: Several risk factors for sphincter tear were identified. Sphincter tear at vaginal delivery is a serious complication, and it is frequently associated with anal incontinence. Special attention should be directed toward risk factors for this complication. Symptoms of anal incontinence should explicitly be sought at follow-up after delivery.     

Mode of delivery and fecal incontinence at midlife: a study of 2,640 women in the Gazel cohort

OBJECTIVE: To estimate obstetric risk factors of fecal incontinence among middle-aged women. METHODS: We conducted a mail survey of the Gazel cohort of volunteers for epidemiologic research. In 2000, a questionnaire on anal incontinence was mailed to 3,114 women who were then between the ages of 50 and 61 years; 2,640 (85%) women returned the completed questionnaire. Fecal incontinence was defined by involuntary loss of stool. Logistic regression was used to estimate the effect of obstetric and general risk factors. RESULTS: Prevalence of fecal incontinence in the past 12 months was 9.5% (250). Significant risk factors for fecal incontinence were completion of high school (adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1-2.0), self-reported depression (OR 2.1, 95% CI 1.6-2.7), overweight or obesity measured by body mass index (BMI) (OR 1.5 for BMI of 25-30, 95% CI 1.1-2.0; OR 1.6 for BMI more than 30, 95% CI 1.1-2.5), surgery for urinary incontinence (OR 3.5, 95% CI 2.0-6.1), and anal surgery (OR 1.7, 95% CI 1.1-2.9). No obstetric variable (parity, mode of delivery, birth weight, episiotomy, or third-degree perineal tear) was significant. Prevalence of fecal incontinence was similar for nulliparous, primiparous, secundiparous, and multiparous women (11.3%, 9.0%, 9.0%, and 10.4%, respectively), and among parous women, it was similar for women with spontaneous vaginal, instrumental (at least one), or only cesarean deliveries (9.3%, 10.0%, and 6.6%, respectively). CONCLUSION: In our population of women in their 50s, fecal incontinence was not associated with either parity or mode of delivery.     

Fecal and urinary incontinence after vaginal delivery with anal sphincter disruption in an obstetrics unit in the United States

OBJECTIVE: The purpose of this study was to estimate the incidence of urinary and bowel incontinence in relation to anal sphincter laceration in primiparous women and to identify factors that are associated with anal sphincter laceration in a unit that uses primarily midline episiotomy. STUDY DESIGN: From January 1, 1997, to March 30, 2000, 2941 questionnaires concerning pelvic floor function 6 months after delivery were mailed to primiparous women who were delivered vaginally at the University of Michigan Medical Center. Charts were reviewed for 2858 deliveries to assess the use of episiotomy and the degree of perineal trauma, along with demographic and pertinent delivery variables. There were 943 women who completed the urinary function questionnaire and 831 women who completed the bowel function questionnaire. Univariate analysis was performed on all covariates. Multiple logistic regression was used for the analysis of the presence of third- or fourth-degree lacerations as the outcome. RESULTS: Nineteen percent of the women who completed the survey had sustained third- or fourth-degree lacerations during childbirth. The women in the sphincter laceration group were more likely (23.0%) to have bowel incontinence than the women in the control group (13.4%) (P<.05). The incidence of worse bowel control was nearly 10 times higher in women with fourth-degree lacerations (30.8%) compared with women with third-degree lacerations (3.6%, P<.001). Macrosomia (odds ratio, 2.19; 95% CI, 1.61, 2.99), forceps-assisted delivery (odds ratio, 4.75; 95% CI, 3.43, 6.57), and vacuum-assisted delivery (odds ratio, 3.51; 95% CI, 2.64, 4.66) were associated with higher risks of third- and fourth-degree lacerations. Midline episiotomy (odds ratio, 2.24; 95% CI, 1.81, 2.77), but not mediolateral (odds ratio, 0.66; 95% CI, 0.375, 1.19), episiotomy was associated with anal sphincter lacerations. More than one half of the women had new onset of urinary incontinence after delivery and reported several lifestyle modifications to prevent leakage. CONCLUSION: Women with third- and fourth-degree lacerations were more likely to have bowel incontinence than women without anal sphincter lacerations. Fourth-degree lacerations appear to affect anal continence greater than third-degree lacerations.     

Fecal and urinary incontinence in primiparous women

OBJECTIVE: To prospectively investigate the relationship between anal sphincter tears and postpartum fecal and urinary incontinence. METHODS: The Childbirth and Pelvic Symptoms study was a prospective cohort study performed by the Pelvic Floor Disorders Network to estimate the prevalence of postpartum fecal and urinary incontinence in primiparous women: 407 with clinically recognized anal sphincter tears during vaginal delivery, 390 without recognized sphincter tears (vaginal controls), and 124 delivered by cesarean before labor. Women were recruited postpartum while hospitalized and interviewed by telephone 6 weeks and 6 months postpartum. We assessed fecal and urinary incontinence symptoms using the Fecal Incontinence Severity Index and the Medical, Epidemiological, and Social Aspects of Aging Questionnaire, respectively. Odds ratios were adjusted for age, race, and clinical site. RESULTS: Compared with the vaginal control group, women in the sphincter tear cohort reported more fecal incontinence (6 weeks, 26.6% versus 11.2%; adjusted odds ratio [AOR] 2.8, 95% confidence interval [CI] 1.8-4.3; 6 months, 17.0% versus 8.2%; AOR 1.9, 95% CI 1.2-3.2), more fecal urgency and flatal incontinence, and greater fecal incontinence severity at both times. Urinary incontinence prevalence did not differ between the sphincter tear and vaginal control groups. Six months postpartum, 22.9% of women delivered by cesarean reported urinary incontinence, whereas 7.6% reported fecal incontinence. CONCLUSION: Women with clinically recognized anal sphincter tears are more than twice as likely to report postpartum fecal incontinence than women without sphincter tears. Cesarean delivery before labor is not entirely protective against pelvic floor disorders. LEVEL OF EVIDENCE: II-3.     

Diagnosis of anal sphincter tears by postpartum endosonography to predict fecal incontinence

OBJECTIVE: To determine whether anal endosonography immediately after vaginal delivery can predict subsequent fecal incontinence. METHODS: We studied nulliparas who delivered vaginally and had no anal sphincter tears (third- or fourth-degree perineal tears) diagnosed clinically by endosonography before any suture of the perineum. The sonographer was unaware of delivery details and the obstetrician and the women were not informed of endosonography results. Therefore, the suture of the perineum and the outcomes were not influenced by sonographer's diagnoses. Three months after delivery, we assessed fecal incontinence by self-administered questionnaires. RESULTS: Clinically undetected tears of the anal sphincter were diagnosed by anal endosonography in 42 of 150 women (28%). The external anal sphincter alone was involved in 30 women (20%), the internal anal sphincter alone in two (1.3%), and both in ten (7%). The postal questionnaire was returned by 144 women. Incontinence was reported by 22 (15%, 95% confidence interval [CI] 10%, 22%), consisting mainly of incontinence to flatus only (16 of 22, 73%, 95% CI 50%, 89%). Clinically undetected anal sphincter tears diagnosed by endosonography were associated with incontinence 3 months after delivery (odds ratio [OR] 8.8; 95% CI 2.9, 26.5). The sensitivity of anal endosonography was 68% (95% CI 49%, 88%) and the positive predictive value 37% (95% CI 22%, 51%). CONCLUSION: Anal endosonography immediately after vaginal delivery allows diagnosis of clinically undetected anal sphincter tears that might be associated with subsequent fecal incontinence.     

The clinical significance of postpartum transperineal ultrasound of the anal sphincter

BACKGROUND AND OBJECTIVE: To evaluate the clinical significance of postpartum anal sphincter damage by transperineal ultrasonography (TPUS) performed on the day of delivery. METHODS: Continence questionnaires were handed out and TPUS was performed on 154 consecutive primiparous women 6-24h after vaginal delivery. At 2 and 6 months later, complaints and sphincteric sonographic appearance were reassessed. The puerperal women's clinical status and sonographic findings in the immediate and late postpartum period were evaluated. RESULTS: Thirty-five (23%) women complained of anal incontinence on the first postpartum day and anal sphincter damage was demonstrated by TPUS in 31 (89%) of them. Four women with anorectal complaints had an intact anal sphincter by TPUS. Follow-up questionnaires, 2 months later, revealed 30 symptomatic women: all of them had sonographically recognized tears on the initial TPUS and 27 of them had positive findings on the TPUS performed 2 months after birth. Six months after delivery, 27 women reported symptoms and all of them had sphincteric disruption evidenced on TPUS performed on the day of delivery. All the women with intact sphincter on the initial TPUS were asymptomatic 6 months later. CONCLUSION: TPUS findings on the day of delivery are related to long-term anorectal complaints, supporting a potential role for TPUS as a screening aid for anal sphincter tears.     

Anal incontinence in women with and those without pelvic floor disorders

OBJECTIVE: To compare the prevalence of anal incontinence and anal sphincter injury in women with pelvic floor disorders (cases) with those in a group of normal control subjects and to evaluate the relationship between sphincter injury and anal incontinence in each group. METHODS: We previously reported the results of a cross-sectional study of 100 women with pelvic floor disorders (> or = stage II pelvic organ prolapse and/or urinary incontinence). In this study, we compared those cases with 90 controls (stage 0 or I pelvic organ prolapse and no urinary incontinence) who completed the Rockwood-Thompson fecal incontinence severity index, in which scoring (0-61) is based on the frequency and type of anal incontinence. All women underwent endoanal ultrasonography, and the internal and external anal sphincters were reported as intact versus disrupted. Chi-square test, Student t test, and logistic regression were used for statistical analysis. RESULTS: Women with pelvic floor disorders were significantly more likely to report anal incontinence (54% versus 17.8%, odds ratio [OR] 5.4, 95% confidence interval [CI] 2.8-10.6, P < .001) and had higher mean fecal incontinence severity index scores (22.3 +/- 13 versus 12.7 +/- 6.3, P = .006) than controls. Cases demonstrated higher rates of anal sphincter defects on ultrasound examination than did controls (52% versus 30%, P = .007). Anal incontinence was significantly associated with anal sphincter injury in women with pelvic floor disorders (OR 36.4, 95% CI 12-114, P < .001) and in controls (OR 5.9, 95% CI 3-11, P = .002). CONCLUSION: Anal incontinence was more common in women with pelvic floor disorders than normal controls and may be due to higher rates of anatomic anal sphincter disruption in this group.     

Risk factors for anal sphincter tear in multiparas

OBJECTIVE: To assess maternal, newborn, and obstetric risk factors associated with anal sphincter tear in multiparous women. METHODS: This case-control study identified 18,779 multiparous vaginal deliveries from 1992 to 2004 from an obstetric automated record database at the University of Alabama at Birmingham. Two hundred eighty-four patients were selected, 145 cases and 139 controls. Variables from the index pregnancy and prior pregnancies were analyzed, and multivariable logistic regression models were constructed to determine significant predictor variables for anal sphincter tear in multiparous women. RESULTS: One hundred forty-five multiparous women with no history of cesarean delivery sustained a sphincter tear. Multivariable logistic regression showed a significant association with episiotomy (odds ratio [OR] 16.3, 95% confidence interval [CI] 7.7-34.4), shoulder dystocia (OR 7.9, CI 1.6-38), forceps delivery (OR 4.7, CI 2.0-11.2), and being married (OR 2.2, CI 1.1-4.6). A second exploratory model that included variables from previous pregnancies, showed that in addition to episiotomy (OR 34.6, CI 8.8-136), shoulder dystocia (OR 11.1, CI 1.3-95.2), forceps delivery (OR 6.1, CI 1.6-23.5), previous sphincter tear (OR 7.7, CI 1.2-48.7), and second stage of labor greater than 1 hour (OR 6.7, CI 1.1-42.5) were associated with tear. CONCLUSION: The strongest clinical risk factors for anal sphincter tear in multiparous women are episiotomy, shoulder dystocia, previous sphincter tear, prolonged second stage of labor, and forceps delivery. LEVEL OF EVIDENCE: II-2.     

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.     

Long-term effects of anal sphincter rupture during vaginal delivery: faecal incontinence and sexual complaints

Objective  To determine the long-term effects of obstetric anal sphincter rupture on the frequency of faecal incontinence and sexual complaints.
Design  Retrospective case–control study.
Setting  Department of Gynaecology and Obstetrics, Ikazia Hospital, The Netherlands.
Population  All 171 women operated for anal sphincter rupture between 1971 and 1990 and 171 controls matched for parity and date of delivery.
Methods  Postal questionnaires regarding faecal incontinence were sent in 1996 and 2005 to all cases and controls with questions regarding sexual complaints added to the questionnaire in 2005.
Main outcome measures  Anorectal complaints defined as any form of faecal incontinence including faecal urgency and faecal soiling. Sexual complaints defined as dyspareunia or faecal incontinence during intercourse.
Results  Sixty-one percent of the women responded to both questionnaires. Anorectal complaints were reported by 38% of case versus 16% of controls in 1996 (risk difference: 0.22, 95% CI 0.10–0.34) and by 61% of cases versus 22% of controls in 2005 (risk difference: 0.41, 95% CI 0.29–0.53). In contrast to the control group, the increase of anorectal complaints in the case group between 1996 and 2005 was highly significant ( P < 0.0001). Postmenopausal state was not associated with an increased risk for faecal incontinence. Dyspareunia was reported by 29% of cases versus 13% of controls ( P = 0.01). Faecal incontinence during intercourse was reported by 13% of cases versus 1% of controls ( P = 0.005).
Conclusions  Obstetric anal sphincter rupture is an important risk factor for sexual complaints and for faecal incontinence increasing with age irrespective of menopausal state.     

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.     

Risks of anal incontinence from subsequent vaginal delivery after a complete obstetric anal sphincter tear.

OBJECTIVE: To assess the influence of various risk factors on long term anal incontinence in women with a complete obstetric tear of the anal sphincter. DESIGN: Postal questionnaire. SETTING: Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark. SUBJECTS: 152 women with complete obstetric tear of the anal sphincter. MAIN OUTCOME MEASURES: Occurrence and duration of anal incontinence in relation to any delivery. RESULTS: 56 of 121 respondents had experienced a subsequent vaginal delivery; 23 (41%) of these had had transient anorectal incontinence directly after the complete tear and four (7%) had permanent anorectal incontinence. In the 23 women with transient anorectal incontinence directly after the complete tear, 9 (39%; 95% CI 19%-59%) developed anorectal incontinence after the next delivery, and this was permanent in four (17.4%; 95% CI 2%-33%). In the 29 women without anorectal incontinence after complete tear, two had transient incontinence of flatus but for less than 14 days after the next delivery. CONCLUSIONS: Transient anal incontinence after a complete tear is a predictor of anal incontinence after subsequent vaginal delivery. The major long term problem in our study of premenopausal women was incontinence of flatus. This possibility should be discussed with the women when a further pregnancy is planned.     

Risk factors for perineal injury during delivery

OBJECTIVE: We sought to identify risk factors for anal sphincter injury during vaginal delivery. STUDY DESIGN: This was a retrospective, case-control study. We reviewed 2078 records of vaginal deliveries within a 2-year period from May 1, 1999, through April 30, 2001. Cases (n = 91) during the study period were defined as parturients who had documentation of greater than a second-degree perineal injury. Control subjects (n = 176), who were identified with the use of a blinded protocol, included women who were delivered vaginally with less than or equal to a second-degree perineal injury. For each patient, we reviewed medical and obstetrics records for the following characteristics: maternal age, race, weight, gestational age, parity, tobacco use, duration of first and second stages of labor, use of oxytocin, use of forceps or vacuum, infant birth weight, epidural use, and episiotomy use. RESULTS: Of the 2078 deliveries that were reviewed, we discovered 91 cases (4.4%) of documented anal sphincter injury. The mean maternal age of our sample was 24.9 +/- 5.9 years). Nearly two thirds (63.2%) were white; 26.7% were black, and 10.1% were of other racial backgrounds. Forceps were used in 51.6% of deliveries that resulted in tears (cases), compared to 8.6% of deliveries without significant tears (control subjects, P <.05). Using cases and control subjects with complete data (cases, 82; control subjects, 144), delivery with forceps was associated with a 10-fold increased risk of perineal injury (odds ratio, 10.8; 95% CI, 5.2-22.3) compared to noninstrumented deliveries. The association was similar after adjustment for age, race, parity, mode of delivery, tobacco use, episiotomy, duration of labor (stages 1 and 2), infant birth weight, epidural, and oxytocin use (odds ratio, 11.9; 95% CI, 4.7-30.4). Nulliparous women were at increased risk for tears (adjusted odds ratio, 10.0; 95% CI, 3.0-33.3) compared with multiparous patients, but parity did not reduce the association between forceps-assisted deliveries and anal sphincter injuries. Increasing fetal weight was also a risk factor in both unadjusted and adjusted analyses. The performance of a midline episiotomy was associated with an increased risk of anal sphincter tear compared with delivery without an episiotomy in the univariate analysis (odds ratio, 4.9; 95% CI, 2.5-9.6), but this association was reduced in the adjusted analysis (odds ratio, 2.5; 95% CI, 1.0-6.0). The increased duration of both the first and second stages of labor increased injury risk in the unadjusted, but not adjusted, analysis. No significant association was observed between case status and the use of oxytocin or epidural anesthesia. Greater, but not significant, increased risk was associated with maternal indications for operative delivery compared with fetal indications. CONCLUSION: Our results are consistent with recent reports that identify forceps delivery and nulliparity as risk factors for recognized anal sphincter injury at the time of vaginal delivery. Further investigation should focus on the determination of whether the association of injury to instrumentation is causal or, in fact, modifiable. Because of the established association between sphincteric muscular damage and anal incontinence, patients should be counseled about the risk of anal sphincter injury when operative vaginal delivery is contemplated. Such patients should be followed closely in the postpartum setting to assess for the development of potential anorectal complaints.     

Does the angle of episiotomy affect the incidence of anal sphincter injury?

OBJECTIVE: Mediolateral episiotomy is associated with lower rates of significant perineal tears than midline episiotomy. However, the relationship between precise angle of episiotomy from the perineal midline and risk of third-degree tear has not been established. This study quantifies this relationship. DESIGN: Case-control study. SETTING: National Maternity Hospital, Dublin, Ireland. SAMPLE: One hundred primiparous women who had undergone right mediolateral episiotomy 3 months previously. METHODS: Two groups of primiparous women were compared. Cases had sustained clinically apparent anal sphincter injury during delivery, while controls had not. The angle of episiotomy measured from the midline was marked on a superimposed sheet of transparent plastic film and measured using a protractor. Data were analysed using Student's t test, chi-square test and logistic regression analysis. MAIN OUTCOME MEASURES: Angle of mediolateral episiotomy from the perineal midline. RESULTS: Fifty-four cases and 46 controls were assessed. Cases were more likely to have undergone assisted delivery and consequently to have been delivered by an obstetrician than by a midwife. The mean angle of episiotomy measured significantly smaller in cases (30 degrees, 95% CI 28-32 degrees) than in controls (38 degrees, 95% CI 35-41 degrees; P<0.001). Analysis showed a 50% relative reduction in risk of sustaining third-degree tear for every 6 degrees away from the perineal midline that an episiotomy was cut. CONCLUSIONS: These results show that a larger angle of episiotomy is associated with a lower risk of third-degree tear and mediolateral episiotomy incisions should be made at as large an angle as possible to minimise the risk of sphincter disruption.     

Urinary and anal incontinence after vacuum delivery

OBJECTIVES: To evaluate urinary and fecal incontinence symptoms, and occult anal sphincter defects in women after vacuum and spontaneous vaginal delivery. STUDY DESIGN: In a case-control study, 50 primiparous women delivered by vacuum extraction were compared to 50 women delivered spontaneously. Urinary and anal incontinence symptoms, pelvic floor muscle strength and sphincter defects on endoanal ultrasound were evaluated 6-24 weeks postpartum. RESULTS: New anal incontinence symptoms after childbirth were found in 30% of the vacuum group compared to 34% of the controls, new urinary incontinence symptoms in 28 and 42%, respectively (not significant). After excluding Grade III perineal tear, sonographic sphincter defects were found in 11 (27.5%) after vacuum delivery compared to 4 (10%) after spontaneous delivery (P<0.05, chi(2)-test). CONCLUSION: Anal and urinary incontinence symptoms are frequent after vaginal delivery. Vacuum delivery causes more sonographic sphincter defects but appears to cause no more harm to pelvic floor function than spontaneous vaginal delivery.     

Risk factors for female anal incontinence: new insight through the Evanston-Northwestern twin sisters study

OBJECTIVE: To evaluate risk factors for anal incontinence using an identical twin sisters study design to provide control over genetic variance. METHODS: A total of 271 identical twin sister pairs (mean age 47 years) completed the validated Colorectal Anal Distress Inventory questionnaire detailing the presence and severity of anal incontinence. Data were analyzed using a stepwise logistic regression with repeated binary measures to account for correlated data within twin pairs. Three different statistical models were used to analyze nonobstetric as well as obstetric risk factors separately. RESULTS: Significant risk factors for anal incontinence and higher Colorectal Anal Distress Inventory anal incontinence subscale scores included age 40 years or older (fecal: odds ratio [OR] 2.82, 95% confidence interval [CI] 1.21-6.0; flatal: OR 1.90, 95% CI 1.11-3.24), menopause (fecal: OR 2.10, 95% CI 1.15-3.8; flatal: OR 2.11, 95% CI 1.43-3.13), increasing parity (parity > or = 2; fecal: OR 3.09, 95% CI 1.25-7.65; flatal: OR 2.72, 95% CI 1.65-4.51), and the presence of stress urinary incontinence (fecal: OR 2.11, 95% CI 1.12-3.98; flatal: OR 1.72, 95% CI 1.14-2.59). Obesity was associated with significantly higher Colorectal Anal Distress Inventory anal incontinence subscale scores (mean difference 5.18, P = .007). Cesarean delivery after initiation of labor was associated with a lower prevalence of anal incontinence than vaginal birth; however, this difference was not statistically significant (17% compared with 4%, P = .11). No anal incontinence was noted in women who had only elective cesarean deliveries. CONCLUSION: Age, menopause, obesity, parity, and stress urinary incontinence are the major risk factors for female anal incontinence.     

Risk factors for third degree perineal ruptures during delivery

Objective To determine risk factors for the occurrence of third degree perineal tears during vaginal delivery.
Design A population-based observational study.
Population All 284,783 vaginal deliveries in 1994 and 1995 recorded in the Dutch National Obstetric Database were included in the study.
Methods Third degree perineal rupture was defined as any rupture involving the anal sphincter muscles. Logistic regression analysis was used to assess risk factors.
Main outcome measures An overall rate of third degree perineal ruptures of 1.94% was found. High fetal birthweight, long duration of the second stage of delivery and primiparity were associated with an elevated risk of anal sphincter damage. Mediolateral episiotomy appeared to protect strongly against damage to the anal sphincter complex during delivery (OR: 0.21, 95% CI: 0.20–0.23). All types of assisted vaginal delivery were associated with third degree perineal ruptures, with forceps delivery (OR: 3.33, 95%-CI: 2.97–3.74) carrying the largest risk of all assisted vaginal deliveries. Use of forceps combined with other types of assisted vaginal delivery appeared to increase the risk even further.
Conclusions Mediolateral episiotomy protects strongly against the occurrence of third degree perineal ruptures and may thus serve as a primary method of prevention of faecal incontinence. Forceps delivery is a stronger risk factor for third degree perineal tears than vacuum extraction. If the obstetric situation permits use of either instrument, the vacuum extractor should be the instrument of choice with respect to the prevention of faecal incontinence.