Risk of Recurrence of Anal Sphincter Lacerations

Counseling women with obstetric anal sphincter injury - Risk of recurrence and the influence of mode of second delivery on subsequent anal incontinence - A systematic review and meta-analysis

Obstetric anal sphincter injury (OASI) is a severe complication of vaginal delivery. Up to 50% of women with OASI will experience anal incontinence at long-term. However, it is uncertain whether an elective cesarean section (CS) in a subsequent pregnancy following OASI decreases the risk of anal incontinence. The aim of this study was to assess the risk of recurrent OASI in a subsequent pregnancy after a first delivery with OASI. Additionally, we wanted to evaluate the impact of recurrent OASI on the risk of anal incontinence, and to determine whether the CS was protective against anal incontinence in women with a first delivery with OASI. Literature searches were made in PubMed, Cochrane, and Embase, the last search was made in May 2024. Studies were screened and study quality was assessed using "SIGN - Methodology Checklist". Thirteen studies (including 3 020 897 women) were included in the meta-analysis on risk of recurrent OASI. OASI in the first delivery increased the risk of recurrent OASI in the second delivery fivefold compared to women without previous OASI OR 4.9 (95%CI 4.0-5.9). The overall risk of acquiring a recurrent OASI was 6.1% (95%CI 5.9%-6.2%). Five studies (including 2 330 women) were included in the meta-analysis assessing the effect of mode of subsequent delivery on anal incontinence. The risk of anal incontinence was non-significantly increased in women with a second vaginal delivery OR 1.1 (95%CI 0.9-1.4). Four studies (including 2 300 women) were included in the meta-analysis on the risk of developing anal incontinence after recurrent OASI. The risk of anal incontinence was increased in women with recurrent OASI compared to women with OASI in the first delivery and a subsequent delivery without OASI OR 1.6 (95%CI 1.3-2.0). In conclusion, we found an increased risk of recurrent OASI in the second delivery for women with a previous OASI, compared to women without previous OASI. The risk of anal incontinence was increased in women with recurrent OASI. The risk of new onset or worsening of anal incontinence was not associated with mode of the second delivery. Women with previous OASI should be informed about the increased risk of recurrence and that elective CS is not necessarily protective against anal incontinence.

Caesarean section and anal incontinence in women after obstetric anal sphincter injury: A systematic review and meta-analysis

BACKGROUND

Approximately 50% women who give birth after obstetric anal sphincter injury (OASI) develop anal incontinence (AI) over their lifetime.

OBJECTIVE

To evaluate current evidence for a protective benefit of planned caesarean section (CS) to prevent AI after OASI.

SEARCH STRATEGY

MEDLINE/PubMed, Embase 1974-2024, CINAHL and Cochrane to 7 February 2024 (PROSPERO CRD42022372442).

SELECTION CRITERIA

All studies reporting outcomes after OASI and a subsequent birth, by any mode.

DATA COLLECTION AND ANALYSIS

Eighty-six of 2646 screened studies met inclusion criteria, with nine studies suitable to meta-analyse the primary outcome of 'adjusted AI' after OASI and subsequent birth. Subgroups: short-term AI, long-term AI, AI in asymptomatic women.

SECONDARY OUTCOMES

total AI, quality of life, satisfaction/regret, solid/liquid/flatal incontinence, faecal urgency, AI in women with and without subsequent birth, change in AI pre- to post- subsequent birth.

MAIN RESULTS

There was no evidence of a difference in adjusted AI after subsequent vaginal birth compared with CS after OASI across all time periods (OR = 0.92, 95% CI 0.72-1.20; 9 studies, 2104 participants, I2 = 0% p = 0.58), for subgroup analyses or secondary outcomes. There was no evidence of a difference in AI in women with or without subsequent birth (OR = 1.00 95% CI 0.65-1.54; 10 studies, 970 participants, I2 = 35% p = 0.99), or pre- to post- subsequent birth (OR = 0.79 95% CI 0.51-1.25; 13 studies, 5496 participants, I2 = 73% p = 0.31).

CONCLUSIONS

Due to low evidence quality, we are unable to determine whether planned caesarean is protective against AI after OASI. Higher quality evidence is required to guide personalised decision-making for asymptomatic women and to determine the effect of subsequent birth mode on long-term AI outcomes.

Predicting perineal trauma during childbirth using data from a general obstetric population

Background

Perineal trauma is a common complication of childbirth and can have serious impacts on long-term health. Few studies have examined the combined effect of multiple risk factors. We developed and internally validated a risk prediction model to predict third and fourth degree perineal tears using data from a general obstetric population.

Methods

Risk prediction model using data from all singleton vaginal deliveries at Cork University Maternity Hospital (CUMH), Ireland during 2019 and 2020. Third/fourth degree tears were diagnosed by an obstetrician or midwife at time of birth and defined as tears that extended into the anal sphincter complex or involved both the anal sphincter complex and anorectal mucosa. We used univariable and multivariable logistic regression with backward stepwise selection to develop the models. Candidate predictors included infant sex, maternal age, maternal body mass index, parity, mode of delivery, birthweight, post-term delivery, induction of labour and public/private antenatal care. We used the receiver operating characteristic (ROC) curve C-statistic to assess discrimination, and bootstrapping techniques were used to assess internal validation.

Results

Of 8,403 singleton vaginal deliveries, 8,367 (99.54%) had complete data on predictors for model development. A total of 128 women (1.53%) had a third/fourth degree tear. Three variables remained in the final model: nulliparity, mode of delivery (specifically forceps delivery or ventouse delivery) and increasing birthweight (per 100 gram increase) (C-statistic: 0.75, 95% CI: 0.71, 0.79). We developed a nomogram to calculate individualised risk of third/fourth degree tears using these predictors. Bootstrapping indicated good internal performance.

Conclusions

Use of our nomogram can provide an individualised risk assessment of third/fourth degree tears and potentially aid counselling of women on their potential risk.

Universal Urogynecologic Consultation and Screening for Fecal Incontinence in Pregnant Women With a History of Obstetric Anal Sphincter Injury: A Cost-Effectiveness Analysis

IMPORTANCE

Obstetric anal sphincter injuries (OASIS) predispose for the development of fecal incontinence (FI), but management of subsequent pregnancy after OASIS is controversial.

OBJECTIVE

We aimed to determine if universal urogynecologic consultation (UUC) for pregnant women with prior OASIS is cost-effective.

STUDY DESIGN

We performed a cost-effectiveness analysis of pregnant women with a history of OASIS modeling UUC compared with no referral (usual care). We modeled the route of delivery, peripartum complications, and subsequent treatment options for FI. Probabilities and utilities were obtained from published literature. Costs using a third-party payer perspective were gathered from the Medicare physician fee schedule reimbursement data or published literature converted to 2019 U.S. dollars. Cost-effectiveness was determined using incremental cost-effectiveness ratios).

RESULTS

Our model demonstrated that UUC for pregnant patients with prior OASIS was cost-effective. Compared with usual care, the incremental cost-effectiveness ratio for this strategy was $19,858.32 per quality-adjusted life-year, below the willingness to pay a threshold of $50,000/quality-adjusted life-year. Universal urogynecologic consultation reduced the ultimate rate of FI from 25.33% to 22.67% and reduced patients living with untreated FI from 17.36% to 1.49%. Universal urogynecologic consultation increased the use of physical therapy by 14.14%, whereas rates of sacral neuromodulation and sphincteroplasty increased by only 2.48% and 0.58%, respectively. Universal urogynecologic consultation reduced the rate of vaginal delivery from 97.26% to 72.42%, which in turn led to a 1.15% increase in peripartum maternal complications.

CONCLUSIONS

Universal urogynecologic consultation in women with a history of OASIS is a cost-effective strategy that decreases the overall incidence of FI, increases treatment utilization for FI, and only marginally increases the risk of maternal morbidity.

Predicting perineal trauma during childbirth using data from a general obstetric population

Background: Perineal trauma is a common complication of childbirth and can have serious impacts on long-term health. Few studies have examined the combined effect of multiple risk factors. We developed and internally validated a risk prediction model to predict third and fourth degree perineal tears using data from a general obstetric population. Methods: Risk prediction model using data from all singleton vaginal deliveries at Cork University Maternity Hospital (CUMH), Ireland during 2019 and 2020. Third/fourth degree tears were diagnosed by an obstetrician or midwife at time of birth and defined as tears that extended into the anal sphincter complex or involved both the anal sphincter complex and anorectal mucosa. We used univariable and multivariable logistic regression with backward stepwise selection to develop the models. Candidate predictors included infant sex, maternal age, maternal body mass index, parity, mode of delivery, birthweight, post-term delivery, induction of labour and public/private antenatal care. We used the receiver operating characteristic (ROC) curve C-statistic to assess discrimination, and bootstrapping techniques were used to assess internal validation. Results: Of 8,403 singleton vaginal deliveries, 8,367 (99.54%) had complete data on predictors for model development. A total of 128 women (1.53%) had a third/fourth degree tear. Three variables remained in the final model: nulliparity, mode of delivery (specifically forceps delivery or ventouse delivery) and increasing birthweight (per 100 gram increase) (C-statistic: 0.75, 95% CI: 0.71, 0.79). We developed a nomogram to calculate individualised risk of third/fourth degree tears using these predictors. Bootstrapping indicated good internal performance. Conclusions: Use of our nomogram can provide an individualised risk assessment of third/fourth degree tears and potentially aid counselling of women on their potential risk.

Risk factors for obstetric anal sphincter injury recurrence: A systematic review and meta-analysis

BACKGROUND

Women with previous obstetric anal sphincter injuries (OASIs) are at a higher risk of recurrence in the subsequent pregnancy, which may lead to the development or worsening of anal incontinence. Due to a lack of evidence, few recommendations can be made about the factors that may affect the risk of OASI recurrence.

OBJECTIVE

We sought to conduct a systematic review and meta-analysis to investigate potential risk factors for recurrent OASIs.

SEARCH STRATEGY

Studies up to May 2019 were identified from PubMed, Scopus, Cochrane Library, and ISI Web of Science.

SELECTION CRITERIA

Studies assessing the impact of risk factors on OASI recurrence in subsequent pregnancies were included. Reviews, letters to the editor, conference abstracts, book chapters, guidelines, Cochrane reviews, and expert opinions were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers. Odds ratio and standardized mean difference were chosen as effect measures. Pooled estimates were calculated using the random-effects model.

MAIN RESULTS

The meta-analysis showed that maternal age, gestational age, occiput posterior presentation, oxytocin augmentation, operative delivery, and shoulder dystocia were associated with the risk of recurrent OASIs in the subsequent delivery.

CONCLUSION

Prenatal and intrapartum risk factors are associated with recurrence of OASI. PROSPERO registration no. CRD42020178125.

Delivery after an obstetric anal sphincter tear

Purpose

The present study aimed to assess the risk of obstetric anal sphincter injuries (OASIS) of a subsequent delivery after the previous OASIS in countries with low (Finland) and high rates (Norway and Sweden) of OASIS.

Methods

This population-based case–control study included women who experienced OASIS 1997–2002. 26,598 women with OASIS were included from countries with low (Finland) and high (Norway and Sweden) OASIS incidences. Each case was matched with one background-adjusted control without OASIS. A follow-up data, including all subsequent deliveries between 1998 and 2011 were then collected. Statistics significances were calculated using chi-square test, test for relative proportions and Students t test, where appropriate.

Results

OASIS in the first birth was associated with increased recurrences in subsequent births, 6.9% vs. 1.7% in Norway (p < 0.001); 4.5% vs. 0.7 (p < 0.001) in Sweden; and 2.1% vs. 0.8% in Finland (p = 0.038). In Norway, more than two deliveries occurred in 4.8% of cases and 6.2% of controls (p = 0.001), 4.2% vs. 5.1% in Sweden (p < 0.001), and 5.7% vs. 6.3% in Finland (p = 0.572). For women with OASIS in a previous delivery, the rates of cesarean deliveries in subsequent pregnancies were 16.4% (7.9% for controls) in Norway, and 16.3% (6.0% for controls) in Sweden, and 50.2% (14.2% for controls) in Finland. In all countries, the differences between cases and controls were significant (p < 0.001).

Conclusion

Next deliveries after OASIS are associated with increased frequency of new OASIS, more cesarean deliveries, and less subsequent deliveries in the high-risk population than women without previous OASIS.

The impact of third- or fourth-degree perineal tears on the second pregnancy: A cohort study of 182,445 Scottish women

This study aimed to investigate the reproductive impact of a third- or fourth-degree tear in primigravid women. A retrospective population-based cohort study was conducted using data from Scottish Morbidity Records (SMR02). Primigravid women with a vaginal birth in Scotland from 1997 until 2010 were included. Exposure was third- or fourth-degree tear in the first pregnancy. The second pregnancy rate, interpregnancy interval and third- or fourth-degree tear in a second pregnancy were the primary outcomes. A nested case-control study was used to determine factors associated with repeat third- or fourth-degree tears in a second vaginal birth. Cox regression analysis and logistic regression were used to look for associations. Initial third- or fourth-degree tear occurred in 2.8% women (5174/182445). The percentage of third- or fourth-degree tears in first vaginal births increased from 1% in 1997 to 4.9% in 2010. There was no difference in having a second pregnancy (adjusted Odds Ratio (aOR) 0.98 (99%CI 0.89–1.09)) or the median interpregnancy interval to second pregnancy (adjusted Hazard Ratio (aHR) 1.01 (99%CI 0.95–1.08)) after an initial third- or fourth-degree tear. Women were over four times more likely to have a repeat injury in a subsequent vaginal birth (n = 149/333, aOR 4.68 (99% 3.52–6.23)) and were significantly more likely to have an elective caesarean section in their second pregnancy (n = 887/3333, 26.6%; 12.75 (11.29–14.40)). Increased maternal age and birthweight ≥4500g were risk factors for repeat injury. Third- and fourth-degree tears are increasing in Scotland. Women do not delay or avoid childbirth after initial third- or fourth-degree tear. However, women are more likely to have a repeat third- or fourth-degree tear or an elective caesarean section in the second pregnancy. Strategies to prevent third- or fourth-degree tears are needed.

Obstetrical Anal Sphincter Injuries (OASIS): Prevention, Recognition, and Repair

OBJECTIVE

To review the evidence relating to obstetrical anal sphincter injuries (OASIS) with respect to diagnosis, repair techniques and outcomes. To formulate recommendations as to patient counselling regarding route of delivery for subsequent pregnancy after OASIS.

OPTIONS

Obstetrical care providers caring for women with OASIS have the option of repairing the anal sphincter using end-to-end or overlapping techniques. They may also be involved in counselling women with prior OASIS regarding the route of delivery for future pregnancies.

OUTCOMES

The outcome measured is anal continence following primary OASIS repair and after subsequent childbirth.

EVIDENCE

Published literature was retrieved through searches of Medline, EMBASE, and The Cochrane Library in May 2011 using appropriate controlled vocabulary (e.g., anal canal, obstetrics, obstetric labour complication, pregnancy complication, treatment outcome, surgery, quality of life) and key words (obstetrical anal sphincter injur*, anus sphincter, anus injury, delivery, obstetrical care, surgery, suturing method, overlap, end-to-end, feces incontinence). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Benefits from implementation of these guidelines include: improved diagnosis of OASIS, optimal functional outcomes following repair, and evidence-based counselling of women for future childbirth.

Risk factors for recurrent obstetric anal sphincter injury (rOASI): a systematic review and meta-analysis

Objectives

The objective of this study was to estimate the risk of recurrent obstetric anal sphincter injury (rOASI) in women who have suffered anal sphincter injury in their previous pregnancy and analyse risk factors for recurrence through a systematic review and meta-analysis.

Data sources

A review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were made in Ovid MEDLINE (1996 to May 2015), PubMed, EMBASE and Google Scholar, including bibliographies and conference proceedings.

Methods of study selection

Observational studies (cohort/case–control) evaluating rOASI and risk factors were selected by two reviewers who also analysed methodological quality of those studies. Pooled odds ratios (OR) for rOASI and individual risk factors were calculated using RevMan 5.3.

Tabulation, integration and results

From the eight studies assessed, overall risk of rOASI was 6.3 % compared with a 5.7 % risk of OASI in the first pregnancy. The risk in parous women with no previous OASI was 1.5 %. Factors that increased the risk in a future pregnancy were instrumental delivery with forceps [OR 3.12, 95 % confidence interval (CI) 2.42–4.01) or ventouse (OR 2.44, 95 % CI 1.83–3.25), previous fourth-degree tear (OR 1.7, 95 % CI 1.24–2.36) and birth weight ≥4 kg (OR 2.29, 95 % CI 2.06–2.54). Maternal age ≥35 years marginally increased the risk (OR 1.16, 95 % CI 1–1.35).

Conclusion

The overall rate of rOASI and associated risk factors for recurrence are similar to the rate and risk factors of primary OASI. Antenatal decisions could be based on assessment of foetal weight and intrapartum decisions based upon the requirement for an instrumental delivery.

Electronic supplementary material

The online version of this article (doi:10.1007/s00192-015-2893-4) contains supplementary material, which is available to authorized users.

The impact of first birth obstetric anal sphincter injury on the subsequent birth: a population-based linkage study

BACKGROUND

With rising obstetric anal sphincter injury (OASI) rates, the number of women at risk of OASI recurrence is in turn increasing. Decisions regarding mode of subsequent birth following an OASI are complex, and depend on a variety of factors. We sought to identify the risk factors for OASI recurrence from first and subsequent births, and to investigate the effect of OASI birth factors on planned caesarean for the second birth.

METHODS

Using two linked population datasets from New South Wales, Australia, we selected women giving birth between 2001 and 2011 with a first birth OASI and a subsequent birth. Multivariable logistic regression was used to identify the association of first and second birth factors with OASI recurrence, and to determine which factors were associated with a planned pre-labour caesarean at the second birth.

RESULTS

Of 6,380 women with a first birth OASI who proceeded to a subsequent birth, 75.4% had a vaginal second birth, 19.4% a pre-labour caesarean, and 5.2% an intrapartum caesarean. Although the OASI recurrence rate of 5.7% was significantly higher than the first birth OASI rate of 4.5% (p < 0.01), this may not reflect a clinically significant increase. Following adjustment for first and second birth factors, first birth diabetes and second birthweight ≥3.5 kg were associated with increased likelihood of OASI recurrence, while first birthweight ≥4.0 kg and second gestation at 37-38 weeks were associated with decreased likelihood. A fourth degree tear at the first birth was the strongest factor associated with planned caesarean at the second birth, with other factors including epidural, spinal or general anaesthetic, birthweight, gestation, country of birth and maternal age.

CONCLUSIONS

Compared with previous reports, the low OASI recurrence rate (approximately one in twenty) may reflect appropriate decision-making about subsequent mode of delivery following first birth OASI. This assertion is supported by evidence of different risk profiles for women who have planned caesareans compared with planned vaginal births.

Interventions for women in subsequent pregnancies following obstetric anal sphincter injury to reduce the risk of recurrent injury and associated harms

BACKGROUND

Perineal damage occurs frequently during childbirth, with severe damage involving injury to the anal sphincter reported in up to 18% of vaginal births. Women who have sustained anal sphincter damage are more likely to suffer perineal pain, dyspareunia (painful sexual intercourse), defaecatory dysfunction, and urinary and faecal incontinence compared to those without damage. Interventions in a subsequent pregnancy may be beneficial in reducing the risk of further severe trauma and may reduce the risk of associated morbidities.

OBJECTIVES

To examine the effects of Interventions for women in subsequent pregnancies following obstetric anal sphincter injury for improving health.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014).

SELECTION CRITERIA

Randomised controlled trials, cluster-randomised trials and multi-arm trials assessing the effects of any intervention in subsequent pregnancies following obstetric anal sphincter injury to improve health. Quasi-randomised controlled trials and cross-over trials were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

No trials were included. In future updates of this review, at least two review authors will extract data and assess the risk of bias of included studies.

MAIN RESULTS

No eligible completed trials were identified. One ongoing trial was identified.

AUTHORS' CONCLUSIONS

No relevant trials were included. The effectiveness of interventions for women in subsequent pregnancies following obstetric anal sphincter injury for improving health is therefore unknown. Randomised trials to assess the relative effects of interventions are required before clear practice recommendations can be made.

Anal incontinence in women with recurrent obstetric anal sphincter rupture: a case control study

OBJECTIVES

To determine the risk of recurrent anal sphincter rupture (ASR), and compare the risk of anal incontinence (AI) after recurrent ASR, with that seen in women with previous ASR who deliver by caesarean section or vaginally without sustaining a recurrent ASR.

METHODS

Women with recurrent ASR between January 2000 and June 2011 were identified at two delivery wards in Copenhagen. The women answered a questionnaire with a validated scoring system for AI (St. Mark`s score), and the results were compared with those obtained in two control groups: women with subsequent uncomplicated vaginal delivery or caesarean section.

RESULTS

There were 93 437 vaginal deliveries. ASR occurred in 5.5% (n = 2851) of the nulliparous and 1.5% (n = 608) of the multiparous women. Recurrent ASR occurred in 8% (n = 49) of whom 50% reported symptoms of AI. We found no difference in the occurrence of AI between women with recurrent ASR, and those who delivered vaginally without repeat ASR (p = 0.37; OR = 2.0) or by caesarean section (p = 0.77; OR = 1.3).

CONCLUSION

Women with a past history of ASR have an 8% risk of recurrence. AI affects half of the women with recurrent ASR. Larger studies are required to confirm our findings.

Third and fourth degree perineal tears--the risk of recurrence in subsequent pregnancy

OBJECTIVE

To assess the risk of recurrence of third- and fourth-degree perineal tears (34DPT) and to determine whether previous 34DPT is an independent risk factor for 34DPT in subsequent deliveries.

METHOD

The study group included all women who had a vaginal delivery complicated by 34DPT (2000-2012, N = 356) and subsequently delivered again in the same medical center (N = 204). The rate of recurrence of 34DPT was compared with a control group of women who had a previous vaginal delivery not complicated by 34DPT (N = 58 581) and had a subsequent delivery in the same time period (N = 23 045).

RESULTS

Women in the past-34DPT group had a higher rate of CS (18.6% versus 10.1%, p < 0.001), fetal head in occiput-posterior position (POP; 2.5% versus 0.7%, p = 0.004) and mediolateral episiotomy (25.5% versus 19.4%, p = 0.03). Women in the past-34DPT group had a higher rate of 34DPT in the subsequent delivery (2.0% versus 0.3%, p < 0.001). The rate of recurrence of 34DPT was considerably higher among women with past fourth-degree tear versus women with past third-degree tear (22.2% versus 1.0%, p < 0.001). 34DPT in previous pregnancy is independently associated with increased risk of 34DPT in subsequent delivery (OR = 4.6, 95%-CI 1.3-15.3).

CONCLUSION

Women who experienced 34DPT in their previous pregnancy have an increased risk for recurrence of 34DPT in subsequent pregnancy, especially in cases of past fourth-degree tears.

Is severe perineal damage increased in women with prior anal sphincter injury?

OBJECTIVE

There is conflicting data in the literature regarding the risk of obstetric anal sphincter laceration in patients with a prior laceration. This retrospective chart review seeks to examine the risk of recurrence of obstetric anal sphincter lacerations.

METHODS

Patients who sustained anal sphincter laceration at delivery during a 13-year time period from January 1991 to December 2003 were identified from the medical records database at Temple University Hospital. All subsequent deliveries in this group of patients were extracted from the database. Chart review was performed on all subsequent deliveries with specific attention to demographic factors such as age, race, parity, etc., maternal weight, fetal weight, presence of maternal diabetes, and labor characteristics such as induction or augmentation of labor, instrumentation at delivery (vacuum or forceps), use of episiotomy, and degree of perineal laceration.

RESULTS

There were 23 451 vaginal deliveries at Temple University Hospital between January 1, 1991 and December 31, 2003. Anal sphincter laceration was noted in 778 subjects. Subsequent deliveries among the group of patients with prior sphincter tears numbered 271. Six (2.4%) patients had recurrence of anal sphincter lacerations, and five of them were third degree lacerations. The rate of recurrent lacerations was not significantly different from the rate of initial lacerations (2.4% vs. 3.3%; odds ratio 0.72, 95% confidence interval 0.33-1.59; p = 0.4). Women who sustained recurrent lacerations were older, more obese (mean weight 92 kg vs. 82 kg), had larger babies (3506 g vs. 3227 g), and were more likely to have episiotomies (66.7% vs. 7%) or instrumental deliveries (33.3 vs. 6.5%).

CONCLUSION

Prior anal sphincter laceration does not result in an increased rate of recurrence. Operative vaginal delivery particularly with episiotomy is a risk factor for both initial and recurrent laceration.

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.

Short-term and long-term effects of obstetric anal sphincter injury and their management

PURPOSE OF REVIEW

During the past decade increasing attention has focused on the problem of obstetric anal sphincter damage. Although risk factors are now well known, the effects of such damage have received less study. This review focuses on the early and long-term problems that may arise subsequent to anal sphincter injury following childbirth and assesses therapeutic options.

RECENT FINDINGS

Up to 25% of women experience altered faecal continence after vaginal delivery, with 4% having persistent symptoms. In those women who have sustained a recognized tear to the sphincter, the quality of primary repair is crucial. Nevertheless, evidence clearly supporting the superiority of overlap over approximation repair is still lacking. The importance of pudendal nerve damage in the aetiology of postpartum faecal incontinence is gaining increasing attention. Augmented biofeedback physiotherapy is the gold standard for treatment of women with such injury, whereas sacral nerve stimulation represents a newer treatment option.

SUMMARY

The short-term and long-term effects of obstetric anal sphincter injury warrant increased attention, because with increasing longevity more women are surviving into their 80s and the prevalence of faecal incontinence in this population will increase if measures are not taken to address the problem. Prevention of such injury is not always possible and management options must be further explored. Adequate primary treatment of third-degree tears is of paramount importance.