Impact of third- and fourth-degree perineal tears at first birth on subsequent pregnancy outcomes: a cohort study

Management After Obstetric Anal Sphincter Injury: Anorectal Manometry and Symptoms Predict Long-Term Fecal Incontinence

INTRODUCTION

Obstetric anal sphincter injury (OASI) is associated with serious morbidity and reduced quality of life. The role of anorectal manometry (ARM) to guide treatment is unclear. We aimed to define the role of ARM and symptom assessment after OASI in predicting anal incontinence at long-term follow-up.

METHODS

Prospective evaluation of 205 consecutive post-OASI women who underwent baseline ARM and symptom assessment in a tertiary setting was undertaken. Ninety-nine women were available for long-term follow-up (median 6.6 years). Associations between post-OASI ARM testing and short-term and long-term anal incontinence were examined in addition to clinical and obstetric factors.

RESULTS

Fourth degree tears and lower anal resting and squeeze pressures were associated with short-term anal incontinence. Women with anal incontinence at baseline and women with lower anal resting pressure were more likely to suffer from long-term fecal incontinence (FI). A best-fit cutoff value of 59 mm Hg for baseline anal resting pressure predicted long-term FI, and none of the short-term asymptomatic women with an anal resting pressure of >59 mm Hg reported FI at long-term follow-up.

DISCUSSION

Symptoms of anal incontinence and ARM in patients after OASI are both useful to predict subsequent long-term FI with a best-fit cutoff of 59 mm Hg for anal resting pressure. This provides rationale for routine ARM and accurate symptom assessment in all patients after OASI, to identify high-risk groups to follow and treat, and it may assist decision making regarding mode of subsequent obstetric deliveries.

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.

Obstetric Anal Sphincter Injury: Interpregnancy Interval and Route of Subsequent Delivery

IMPORTANCE

Knowledge on the interpregnancy interval (IPI) among women with an obstetric anal sphincter injury (OASI) is both limited and not well understood.

OBJECTIVES

The objectives of this study were to describe the IPI among women with OASI and to compare women with OASI based on the route of subsequent obstetric delivery and OASI recurrence.

STUDY DESIGN

This was a retrospective single-cohort study of women who had an OASI between 2013 and 2015 at a tertiary academic medical center. Demographics, obstetric delivery data, postpartum sequelae, and subsequent pregnancy delivery data from 2013 to 2021 were collected. The IPI was defined as the time from date of first vaginal delivery to date of conception of the subsequent pregnancy. Women without a subsequent pregnancy were censored at the date of last contact. The IPI was evaluated using a survival analysis (Kaplan-Meier estimator).

RESULTS

A total of 287 women experienced an OASI, and subsequent pregnancy occurred for 178 (62.0%) women. The median IPI was 26.4 months (95% confidence interval: 23.7-29.9) for women with a prior OASI. Of the 97 women who did not have a subsequent pregnancy documented during the study, the median follow-up was 64.0 months (interquartile range: 5.7-80.0). Subsequent delivery route data were available for 171 women; of those, 127 (74.3%) experienced a subsequent vaginal delivery and 44 (25.7%) experienced a cesarean delivery. Of the 127 women who experienced a subsequent vaginal delivery, 3 (2.4%) experienced a recurrent OASI.

CONCLUSION

The IPI among women with OASI is similar to the IPI for all women in Ohio and in the United States.

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.

Risk Factors for Anal Continence Impairment Following a Second Delivery after a First Traumatic Delivery: A Prospective Cohort Study

Postpartum anal incontinence is common. After a first delivery (D1) with perineal trauma, follow-up is advised to reduce the risk of anal incontinence. Endoanal sonography (EAS) may be considered to evaluate the sphincter and in case of sphincter lesions to discuss cesarean section for the second delivery (D2). Our objective was to study the risk factors for anal continence impairment following D2. Women with a history of traumatic D1 were followed before and 6 months after D2. Continence was measured using the Vaizey score. An increase ≥2 points after D2 defined a significant deterioration. A total of 312 women were followed and 67 (21%) had worse anal continence after D2. The main risk factors for this deterioration were the presence of urinary incontinence and the combined use of instruments and episiotomy during D2 (OR 5.12, 95% CI 1.22-21.5). After D1, 192 women (61.5%) had a sphincter rupture revealed by EAS, whereas it was diagnosed clinically in only 48 (15.7%). However, neither clinically undiagnosed ruptures nor severe ruptures were associated with an increased risk of continence deterioration after D2, and cesarean section did not protect against it. One woman out of five in this population had anal continence impairment after D2. The main risk factor was instrumental delivery. Caesarean section was not protective. Although EAS enabled the diagnosis of clinically-missed sphincter ruptures, these were not associated with continence impairment. Anal incontinence should be systematically screened in patients presenting urinary incontinence after D2 as they are frequently associated.

The association between episiotomy or OASIS at vacuum extraction in nulliparous women and subsequent prelabor cesarean delivery: A nationwide observational study

INTRODUCTION

Severe perineal injuries at childbirth affect women's postnatal health, including future childbirths. First births with vacuum extraction carry an increased risk of obstetric anal sphincter injuries (OASIS). Lateral or mediolateral episiotomy at vacuum extraction may decrease the risk of OASIS. Our aim was to assess whether lateral or mediolateral episiotomy, or OASIS, at vacuum extraction in nulliparous women is associated with prelabor cesarean delivery in the subsequent childbirth.

MATERIAL AND METHODS

This is a nationwide observational study using data from the Swedish Medical Birth Register, including women having a first birth with vacuum extraction and a second birth in 2000-2014. Both births were live, single, cephalic, ≥34 gestational weeks without malformations. The association between episiotomy or OASIS in the first birth and prelabor cesarean delivery in the second birth was examined using univariate and multivariate logistic regression with inverse probability of treatment weighting, and interaction analysis. Main outcome measure was prelabor cesarean delivery in the second birth.

RESULTS

In total, 44 656 women with vacuum extraction at their first birth were included. The rate of prelabor cesarean delivery in the second birth was 5.9% (824 of 13 950) in women with episiotomy, compared with 6.0% (1830 of 30 706) in women without episiotomy. Thus, women with episiotomy did not have an increased risk of prelabor cesarean delivery (adjusted odds ratio [aOR] 1.00, 95% confidence interval [95% CI] 0.83-1.20) compared with women without episiotomy. For comparison, the rate of prelabor cesarean delivery in the second birth was 20.6% (1275 of 6176) in women with OASIS, compared with 3.6% (1379 of 38 480) in women without OASIS (aOR 6.57, 95% CI 5.97-7.23). There was no interaction between episiotomy and OASIS.

CONCLUSIONS

Lateral or mediolateral episiotomy at vacuum extraction in nulliparous women did not increase the risk of prelabor cesarean delivery in the subsequent childbirth. OASIS increased the odds of prelabor cesarean delivery more than sixfold.

Patterns in Second Stage Labor Care Practices Associated With Genital Tract Injury and Postpartum Hemorrhage During Physiologic Birth: A Latent Mixture Model Analysis

INTRODUCTION

Genital tract injury during childbirth contributes to short and long-term problems, including postpartum hemorrhage, incontinence, and pelvic organ prolapse. The purpose of this study was to examine which sets of second stage management techniques employed by midwives attending births in the community setting are associated with genital tract injury and subsequent postpartum hemorrhage.

METHODS

Data from primiparous individuals within the Midwives Alliance of North America (MANA) Stats 2.0 (2004–2009) database were used for this analysis. Latent mixture modeling identified classes (groups) within the sample that are most similar based on 11 different characteristics of second stage management as noted by midwives in their birth notes, including hands-on management techniques during birth, maternal positioning at birth, and water birth.

RESULTS

Three classes of second stage management techniques best fit this complex dataset. The patterns of techniques used by midwives were only marginally associated with better or worse genital tract outcomes independent of other factors. Two covariables, however, advanced maternal age (OR1.60, 95% CI 1.09–2.34) and births with low fetal heart rate during second stage (OR2.82, 95% CI 1.93–4.10)—were associated with severe genital tract injury. Postpartum hemorrhage was more likely for the two classes where midwives used more hands-on management during second stage, even when considering presence of genital tract injury (OR1.33, 95% CI 1.09–1.63). This study highlights the complex second stage circumstances that interact with management techniques, which together shape or contribute to both genital tissue and hemorrhage outcomes.

Prolonged Second Stage of Labor and Anal Sphincter Injury in a Contemporary Cohort of Term Nulliparas

OBJECTIVE

This study aimed to assess whether a prolonged second stage of labor is an independent predictor of obstetric anal sphincter injury (OASI) in a contemporary cohort of nulliparous and term parturients, and to evaluate whether predelivery factors can accurately predict OASI.

STUDY DESIGN

This was a nested case-control study within a cohort of consecutive nulliparous term parturients with a singleton gestation who underwent a vaginal delivery at a single institution between January 2014 and January 2015. Cases were defined as women with a third- or fourth-degree laceration at the time of delivery, and controls were women without a third- or fourth-degree laceration. A prolonged second stage was defined as a second stage of ≥3 hours. Univariable and multivariable regression analyses were performed to examine the relationship between prolonged second stage of labor and third- or fourth-degree lacerations. Receiver operator curves were developed to assess the predictive capacity of predelivery information for third- and fourth-degree lacerations.

RESULTS

Of 1,197 births, 63 women had third- or fourth-degree lacerations (5.3%). With each additional hour of the second stage, the rate of OASI increased, with 2.9% of women with a second stage of <1 hour with OASI, 3.5% between 1 and 2 hours, 5.7% between 2 and 3 hours, 7.8% between 3 and 4 hours, 16.1% between 4 and 5 hours, and 28.6% among women with a second stage length >5 hours (p < 0.001). In multivariable regression analysis, operative vaginal delivery (adjusted odds ratio [aOR] = 5.92, 95% confidence interval [CI]: 3.17-11.07) and a prolonged second stage (aOR = 1.92, 95% CI: 1.06-3.51) were independent predictors of third- and fourth-degree lacerations. A predictive model was developed from these results (area under the curve [AUC] = 0.75, 95% CI: 0.68-0.81).

CONCLUSION

Prolonged second stage of labor is a predictor of OASI, after adjustment for operative vaginal delivery. A model using predelivery risk factors has a reasonable prediction of OASI.

KEY POINTS

· Prolonged second stage labor is associated with obstetric anal sphincter injury in term nulliparas.. · Predelivery risk factors reasonably predict obstetric anal sphincter injury in term nulliparas.. · Improved models are needed for clinical risk-stratification..

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.

The effect of two midwives during the second stage of labour to reduce severe perineal trauma (Oneplus): a multicentre, randomised controlled trial in Sweden

BACKGROUND

Severe perineal trauma (SPT) affecting the anal sphincter muscle complex is a serious complication following childbirth, associated with short-term and long-term maternal morbidity. Effective preventive strategies are still scarce. The aim of the Oneplus trial was to test the hypothesis that the presence of a second midwife during the second stage of labour, with the purpose of preventing SPT, would result in fewer injuries affecting the anal sphincter than if attended by one midwife.

METHODS

In this multicentre, randomised, controlled parallel group, unmasked trial done at five obstetric units in Sweden, women were randomly assigned to be assisted by either one or two midwives in late second stage. Nulliparous women and women planning the first vaginal birth after caesarean section who were age 18-47 years were randomly assigned to an intervention when reaching the second stage of labour. Further inclusion criteria were gestational week 37+0, carrying a singleton live fetus in vertex presentation, and proficiency in either Swedish, English, Arabic, or Farsi. Exclusion criteria were a multiple pregnancy, intrauterine fetal demise, a planned caesarean section, or women who were less than 37 weeks pregnant. Randomisation to the intervention group of two midwives or standard care group of one midwife (1:1) was done using a computer-based program and treatment groups were allocated by use of sealed opaque envelopes. All women and midwives were aware of the group assignment, but the statistician from Clinical Studies Forum South, who did the analyses, was masked to group assignment. Midwives were instructed to implement existing prevention models and the second midwife was to assist on instruction of the primary midwife, when asked. Midwives were also instructed to complete case report forms detailing assistance techniques and perineal trauma prevention techniques. The primary outcome was the proportion of women who had SPT, for which odds ratios (ORs) and 95% CIs were calculated, and logistic regression was done to adjust for study site. All analyses were done according to intention to treat. The trial is registered with ClinicalTrials.gov, NCT0377096.

FINDINGS

Between Dec 10, 2018, and March 21, 2020, 8866 women were assessed for eligibility, and 4264 met the inclusion criteria and agreed to participate. 3776 (88·5%) of 4264 women were randomly assigned to an intervention after reaching the second stage of labour. 1892 women were assigned to collegial assistance (two midwives) during the second stage of labour and 1884 women were assigned to standard care (one midwife). 13 women in each group did not meet the inclusion criteria and were excluded. After further exclusions, 1546 women spontaneously gave birth in the intervention group and 1513 in the standard care group. 1546 women in the intervention group and 1513 in the standard care group were included in the intention-to-treat analysis of the primary outcome. There was a significant reduction in SPT in the intervention group (3·9% [61 of 1546] vs 5·7% [86 of 1513]; adjusted OR 0·69 (0·49-0·97).

INTERPRETATION

The presence of two midwives during the active second stage can reduce SPT in women giving birth for the first time.

FUNDING

The Swedish Research Council for Health, Working Life and Welfare; Jan Hains Research Foundation; and Skane County Council's Research and Development Foundation.

Obstetric anal sphincter injury by maternal origin and length of residence: a nationwide cohort study

OBJECTIVE

To estimate the association between maternal origin and obstetric anal sphincter injury (OASI), and assess if associations differed by length of residence.

DESIGN

Population-based cohort study.

SETTING

The Medical Birth Registry of Norway.

POPULATION

Primiparous women with vaginal livebirth of a singleton cephalic fetus between 2008 and 2017 (n = 188 658).

METHODS

Multivariable logistic regression models estimated adjusted odds ratios (aORs) for OASI with 95% CI by maternal region of origin and birthplace. We stratified models on length of residence and paternal birthplace.

MAIN OUTCOME MEASURES

OASI.

RESULTS

Overall, 6373 cases of OASI were identified (3.4% of total cohort). Women from South Asia were most likely to experience OASI (6.2%; aOR 2.24, 95% CI 1.87-2.69), followed by those from Southeast Asia, East Asia & the Pacific (5.7%; 1.59, 1.37-1.83) and Sub-Saharan Africa (5.2%; 1.85, 1.55-2.20), compared with women originating from Norway. Among women born in the same region, those with short length of residence in Norway (0-4 years), showed the highest odds of OASI. Migrant women across most regions of origin had the lowest risk of OASI if they had a Norwegian partner.

CONCLUSIONS

Primiparous women from Asian regions and Sub-Saharan Africa had up to two-fold risk of OASI, compared with women originating from Norway. Migrants with short residence and those with a foreign-born partner had higher risk of OASI, implying that some of the risk differential is due to sociocultural factors. Some migrants, especially new arrivals, may benefit from special attention during labour to reduce morbidity and achieve equitable outcomes.

TWEETABLE ABSTRACT

Anal sphincter injury during birth is more common among Asian and Sub-Saharan migrants and particularly among recent arrivals.

Management of obstetric anal sphincter injury: Colorectal surgeons' perspectives in Australia and New Zealand

BACKGROUND

Obstetric anal sphincter injuries (OASIs) are a significant complication of vaginal delivery, and a leading cause of anal incontinence in women.

AIMS

The aims were to explore the management of OASIs in Australia and New Zealand (ANZ) by colorectal surgeons and how this compares with current recommendations and international experience, and to identify the deterrents to the provision of best-practice care among colorectal surgeons.

MATERIALS AND METHODS

Three hundred colorectal surgeons of the Colorectal Surgical Society of ANZ were mailed questionnaires. Areas of interest included: surgeon demographics; exposure to OASIs; understanding of current recommendations; and opinions regarding the importance of symptoms and assessment tools in OASIs.

RESULTS

There were 94 completed questionnaires (response rate 31.3%). Fifty-seven surgeons (60.6%) reported low exposure to OASIs during their fellowship training. Greater than 90% believed patients with grade three tears and above should have anal sphincter assessment. Sixty-six (70.2%) reported that they routinely review women who have had OASIs. However, 56.4% were unaware if their obstetrics department followed a standard protocol for OASIs. Surgeons practising in metropolitan centres reported higher rates of their obstetrics department following a protocol (P = 0.013), and greater access to investigative tools (P < 0.001), when compared to rural-based surgeons.

CONCLUSIONS

Most ANZ colorectal surgeons have had minimal training in OASI management. Colorectal surgeons are more commonly involved with OASI patients in the non-acute setting. Management protocols involving a multidisciplinary team of both colorectal surgeons and obstetricians should be clearly defined, and the gap between metropolitan and rural centres needs to be reviewed.

The Incidence of and Predictors for Severe Perineal Trauma and Intact Perineum in Women Having a Waterbirth in England: A Hospital-Based Study

Background: To determine the incidence of and predictors for obstetric anal sphincter injuries (OASIS) and intact perineum in women giving birth in the water and compare with the general obstetric population. Materials and Methods: Data were retrospectively collected for women who had singleton cephalic presentation vaginal births in the water and the general obstetric population between August 2007 and December 2017. Results: We identified 1,007 women who had a waterbirth and 36,924 women from the general obstetric population. There was no significant difference in the incidence of OASIS between waterbirths and the general obstetric population (2.3% vs. 2.0%). Having a waterbirth was associated with a lower probability for an intact perineum (odds ratio [OR] = 0.83; confidence interval [95% CI]: 0.73-0.94) when compared with the general obstetric population (44.7% vs. 51.3%). Nulliparous women with a waterbirth when compared with multiparous women had an eightfold higher likelihood for the occurrence of OASIS (OR = 8.28; 95% CI: 2.64-25.86). The risk for a higher degree of OASIS was associated with increased maternal age in the total sample (OR = 1.08; 95% CI: 1.06-1.11) and with a lower body mass index (BMI) at booking in multiparous women (OR = 0.96; 95% CI: 0.92-0.99). The risk for any type of perineal trauma was associated with increased maternal age in the total sample (OR = 1.10; 95% CI: 1.07-1.13) and with a lower BMI at booking in multiparous women (OR = 0.95; 95% CI: 0.91-0.99). Conclusions: We found that giving birth in the water reduced the chance of having an intact perineum. We have also shown that nulliparity, increased maternal age in all women, and a lower BMI at booking in multiparous were associated with OASIS and lower rates of intact perineum in waterbirths.

Women's experience of obstetric anal sphincter injury following childbirth: An integrated review

BACKGROUND

Perineal injury during childbirth is a very common event which affect women during childbirth. Significant morbidities are associated with third-and-fourth degree perineal tears in particular, also referred to as obstetric anal sphincter injuries (OASIS). With an increasing global birth rate and rising interventions in birth, the incidence of perineal trauma following vaginal birth is increasing on an international scale, impacted also by more accurate classification and definitions of OASIS and increased pre-existing co morbidities amongst affected women. The consequences of OASIS can be physically and psychologically distressing for affected women and have significant impact on quality of life.

METHODOLOGY

The aim of this integrative review was to examine women's experience of OASIS following childbirth using a systematic approach. This is presented in a five-stage process that includes problem identification, literature search, data extraction and evaluation, data analysis and presentation of results. A number of academic electronic databases were systematically searched and results are presented and analysed. Results of the complete search are presented in PRISMA format. Eight papers, which were assessed for quality using an appropriate appraisal tool, are included in the review and thematic analysis used to identify themes.

FINDINGS

The themes identified were; psychological consequences, the role of the health care professionals and implications for future pregnancies. Psychological consequences included anxiety, loneliness, isolation, shame, fear, many of which were associated with physical ramifications of OASIS and how these feelings affect activities of daily living. The importance of access to and support from health care professionals was highlighted. The impact the experience of OASIS had on women's decisions about future pregnancies was also evident.

CONCLUSION

The association between OASIS and maternal quality of life following childbirth can be substantial as evidenced by this literature review. The review identifies the need for improvement in the care and management of these women to alleviate the physical and psychological consequences of OASIS, including decisions in relation to future pregnancies and childbirth. Health care professionals caring for women in pregnancy and childbirth need to be educated and informed on the sequelae of OASIS, to ensure appropriate information and support is provided to these women and their families. Such knowledge may enable health care professionals to alleviate symptoms associated with OASIS and help women make sense and cope with their experiences.

Temporal decline in the improved detection rates following OASIS workshops

INTRODUCTION AND HYPOTHESIS

To evaluate the long-term sustainability of the effect of a hands-on workshop on the diagnosis of deliveries complicated by obstetrical anal sphincter injuries (OASIS).

METHODS

A population-based retrospective cohort study looking over a 4-year period, 1 year before and 3 years after an OASIS workshop. All deliveries that took place at the Soroka University Medical Center during the study period were included. Data were collected from the obstetrical electronic database. Interrupted time series analysis assessing the change in the OASIS detection rate over time from the workshop was conducted, assuming that the OASIS rate remained constant during the study period.

RESULTS

During the study period, 147 parturients suffered from OASIS. The baseline characteristics of the patients before and after the workshop did not differ. In the year following the workshop a significant increase in the detection rate was noted compared with the year prior to the workshop. In an interrupted time series analysis, the improved detection rate declined with time. In the last year following the workshop the detection rate declined, almost reaching the pre-workshop rate.

CONCLUSIONS

Attending an OASIS workshop increases the detection rate in the year following the workshop but declines gradually. To maximize its benefits, the workshop must be repeated periodically.

Risk factors for the recurrence of obstetrical anal sphincter injury and the role of a mediolateral episiotomy: an analysis of a national registry

OBJECTIVE

The assessment of risk factors, including mediolateral episiotomy (MLE), for the recurrence of obstetric anal sphincter injury (rOASI).

DESIGN

Population-based cohort study.

SETTING

Data from the nationwide database of the Dutch Perinatal Registry (Perined).

POPULATION

A cohort of 391 026 women at term, of whom 9943 had an OASI in their first delivery and had a second vaginal delivery of a liveborn infant in cephalic position.

METHODS

Possible risk factors were tested for statistical significance using univariate and multivariate logistic regression analysis.

MAIN OUTCOME MEASURES

Rate of rOASI.

RESULTS

The rate of rOASI was 5.8%. Multivariate analysis identified a birthweight of ≥4000 g (adjusted OR, aOR, 2.1, 95% CI 1.6-2.6) and a duration of second stage of ≥30 minutes (aOR 1.8, 95% CI 1.4-2.3) as statistically significant risk factors for rOASI. Mediolateral episiotomy was associated with a statistically significant lower rate of rOASI in spontaneous vaginal delivery (SVD) (aOR 0.4, 95% CI 0.3-0.5) and in operative vaginal delivery (OVD) (aOR 0.2, 95% CI 0.1-0.5).

CONCLUSIONS

Women with a history of OASI have a higher rate of OASI in their next delivery. Duration of the second stage of ≥30 minutes and a birthweight of ≥4000 g are significantly associated with an increased rate of rOASI. Mediolateral episiotomy is associated with a significantly lower rate of rOASI in both SVD and OVD.

TWEETABLE ABSTRACT

Mediolateral episiotomy is associated with a significant lower recurrence rate of OASI in women with an OASI in their first delivery.

Maternal outcomes in subsequent delivery after previous obstetric anal sphincter injury (OASI): a multi-centre retrospective cohort study

Introduction and hypothesis

Women with a history of obstetric anal sphincter injury (OASI) are at increased risk of recurrence (rOASI) at subsequent delivery; however, evidence regarding the factors influencing this risk is limited. Furthermore, little is known about what factors influence the decision to alternatively deliver by elective caesarean section (ELLSCS).

Methods

Retrospective univariate and multivariate logistic regression analysis of prospectively collected data from four NHS electronic maternity databases including primiparous women sustaining OASIS during a singleton, term, cephalic, vaginal delivery between 2004 and 2015, who had a subsequent delivery.

Results

Two thousand two hundred seventy-two women met the criteria; 10.2% delivering vaginally had a repeat OASI and 59.4% had a second-degree tear. Women having an ELLSCS were more likely to be Caucasian, older, have previously had an operative vaginal delivery (OVD) and have a more severe degree of OASI. Positive predictors for rOASI were increased birth weight and maternal age at both index and subsequent deliveries, a more severe degree of initial OASI and Asian ethnicity. The overall mediolateral episiotomy (MLE) rate was 15.6%; 77.2% of those who had an episiotomy sustained no spontaneous perineal trauma. Only 4.4% of women with a rOASI had an MLE, whilst the MLE rate was 16.9% in those without a recurrence (p < 0.001). MLE decreased the risk of rOASI by 80%. Birth weight > 4 kg increased the risk 2.5 fold.

Conclusions

Women with previous OASIS are at an increased risk of recurrence. A more liberal use of MLE during subsequent vaginal delivery could significantly reduce the risk of recurrence.

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.

Swine Vagina Under Planar Biaxial Loads: An Investigation of Large Deformations and Tears

Vaginal tears are very common and can lead to severe complications such as hemorrhaging, fecal incontinence, urinary incontinence, and dyspareunia. Despite the implications of vaginal tears on women's health, there are currently no experimental studies on the tear behavior of vaginal tissue. In this study, planar equi-biaxial tests on square specimens of vaginal tissue, with sides oriented along the longitudinal direction (LD) and circumferential direction (CD), were conducted using swine as animal model. Three groups of specimens were mechanically tested: the NT group (n = 9), which had no pre-imposed tear, the longitudinal tear (LT) group (n = 9), and the circumferential tear (CT) group (n = 9), which had central pre-imposed elliptically shaped tears with major axes oriented in the LD and the CD, respectively. Through video recording during testing, axial strains were measured for the NT group using the digital image correlation (DIC) technique and axial displacements of hook clamps were measured for the NT, LT, and CT groups in the LD and CD. The swine vaginal tissue was found to be highly nonlinear and somewhat anisotropic. Up to normalized axial hook displacements of 1.15, no tears were observed to propagate, suggesting that the vagina has a high resistance to further tearing once a tear has occurred. However, in response to biaxial loading, the size of the tears for the CT group increased significantly more than the size of the tears for the LT group (p = 0.003). The microstructural organization of the vagina is likely the culprit for its tear resistance and orientation-dependent tear behavior. Further knowledge on the structure–function relationship of the vagina is needed to guide the development of new methods for preventing the severe complications of tearing.

Obstetric Anal Sphincter Injuries at Vaginal Delivery: A Review of Recently Published National Guidelines

Importance

Obstetric anal sphincter injuries (OASISs) complicate approximately 1 in 10 deliveries.

Objective

The aims of this study were to review and compare recommendations from recently published national guidelines regarding OASISs at vaginal delivery.

Evidence Acquisition

Three national guidelines on OASISs at vaginal delivery are presented through a descriptive review: Royal College of Obstetricians and Gynaecologists on "The Management of Third- and Fourth-Degree Perineal Tears," American College of Obstetricians and Gynecologists on "Prevention and Management of Obstetric Lacerations at Vaginal Delivery," and Society of Obstetricians and Gynaecologists of Canada on "Obstetrical Anal Sphincter Injuries (OASIS): Prevention, Recognition, and Repair." These guidelines were summarized and compared in terms of prevention and management of OASISs. Quality of evidence was also reviewed based on method of reporting for each guideline.

Results

This published evidence reflects the differences between the national recommendations on the prevention and management of OASISs. Especially, as for the prevention of OASIS, routine use of episiotomy is not recommended, whereas warm perineal compresses and perineal massage during the second stage of labor seem to have a protective role. In the management of OASIS, special care is needed during the repair process of the torn anorectal mucosa and the internal and external anal sphincter. The postoperative use of broad-spectrum antibiotics, oral laxatives, and analgesia is also recommended.

Conclusions

Summarized guidelines can have an impact on special care in prevention and management of OASIS; this may support the reduction of morbidity associated with that entity.

An interprofessional approach to prevent recurrent obstetric anal sphincter injury (OASIS): A case report

Successful outcomes in this case are consistent with the American College of Obstetricians and Gynecologist (ACOG) guidelines for preventing OASIS. The interprofessional birth care team (IBCT) model exemplified by this case focuses on best practice in promoting a family's preferences for physiologic birth and preventing recurrent OASIS.

Impact of electronic and blended learning programs for manual perineal support on incidence of obstetric anal sphincter injuries: a prospective interventional study

BACKGROUND

Obstetric anal sphincter injuries (OASIS) are associated with anal incontinence, dyspareunia and perineal pain. Bimanual perineal support technique (bPST) prevents OASIS. The aim of this study was to assess the effect of two different bPST training-methods on OASIS incidence.

METHODS

This is a prospective-interventional quality improvement study conducted in two Palestinian maternity units between June 1 2015 and December 31 2016. Women having spontaneous or operative vaginal-delivery at ≥24 gestational-weeks or a birthweight of ≥1000 g (n = 1694) were recruited and examined vaginally and rectally immediately after vaginal birth by a trained assessor. Data on baseline OASIS incidence were collected during Phase-1 of the study. Subsequently, birth attendants in both maternity units were trained in bPST using two training modalities. A self-directed electronic-learning (e-learning) using an animated video was launched in phase-2 followed by a blended learning method (the animated e-learning video+ structured face-to-face training) in phase-3. OASIS incidence was monitored during phases-2 and 3. Variations in OASIS incidence between the three phases were assessed using Pearson-χ²-test (or Fisher's-Exact-test). The impact of each training-method on OASIS incidence was assessed using logistic-regression analysis.

RESULTS

A total of 1694 women were included; 376 in phase-1, 626 in phase-2 and 692 in phase-3. Compared to Phase-1, OASIS incidence was reduced by 45% (12.2 to 6.7%, aOR: 0.56, CI; 0.35-0.91, p = 0.018) and 74% (12.2 to 3.2%, aOR, 0.29, CI; 0.17-0.50, p < 0.001) in phases-2 and 3, respectively. There was also a significant reduction in OASIS incidence by 52% from phase-2 to phase-3 (6.7% (42/626) to 3.2% (22/692), p = 0.003). These reductions reached statistical significance among parous-women only (aOR: 0.18, CI; 0.07-0.49, p = 0.001) after the first training method tested in phase-2. However, the reduction was significant among both primiparous (aOR: 0.39, CI; 0.21-0.74, p = 0.004) and parous-women (aOR: 0.11, CI; 0.04-0.32, p < 0.001) after implementing the blended learning method in phase-3.

CONCLUSION

The animated e-learning video had a positive impact on reducing OASIS incidence. However, this reduction was enhanced by the use of a blended learning program combining both e- learning and face-to-face training modalities.

STUDY REGISTRATION NUMBER

ClinicalTrialo.gov identifier: NCT02427854 , date: 28 April 2015.

[Definition, epidemiology and risk factors of obstetric anal sphincter injuries: CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVES

The aim of this review was to agree on a definition of the obstetric anal sphincter injuries (OASIS), to determine the prevalence and risk factors.

METHODS

A comprehensive review of the literature on the obstetric anal sphincter injuries (OASIS), establishment of levels of evidence (NP), and grades of recommendation according to the methodology of the recommendations for clinical practice.

RESULTS

To classify obstetric anal sphincter injuries (OASIS), we have used the WHO-RCOG classification, which lists 4 degrees of severity. To designate obstetric anal sphincter injuries, we have used the acronym OASIS, rather than the standard French terms of "complete perineum" and "complicated complete perineum". OASIS with only isolated involvement of the EAS (3a and 3b) appears to have a better functional prognosis than OASIS affecting the IAS or the anorectal mucosa (3c and 4) (LE3). The prevalence of women with ano-rectal symptoms increases with the severity of the OASIS (LE3). In the long term, 35-60% of women who had an OASIS have anal or fecal incontinence (LE3). The prevalence of an OASI in the general population is between 0.25 to 6%. The prevalence of OASIS in primiparous women is between 1.4 and 16% and thus, should be considered more important than among the multiparous women (0.4 to 2.7%). In women with a history of previous OASIS, the risk of occurrence is higher and varies between 5.1 and 10.7% following childbirth. The priority in this context remains the training of childbirth professionals (midwives and obstetricians) to detect these injuries in the delivery room, immediately after the birth. The training and awareness of these practitioners of OASIS diagnosis improves its detection in the delivery room (LE2). Professional experience is associated with better detection of OASIS (LE3) (4). Continuing professional education of obstetrics professionals in the diagnosis and repair of OASIS must be encouraged (Grade C). In the case of second-degree perineal tear, the use of ultrasound in the delivery room improves the diagnosis of OASIS (LE2). Ultrasound decreases the prevalence of symptoms of severe anal incontinence at 1 year (LE2). The diagnosis of OASIS is improved by the use of endo-anal ultrasonography in post-partum (72h-6weeks) (LE2). The principal factors associated with OASIS are nulliparity and instrumental (vaginal operative) delivery; the others are advanced maternal age, history of OASIS, macrosomia, midline episiotomy, posterior cephalic positions, and long labour (LE2). The presence of a perianal lesion (perianal fissure, or anorectal or rectovaginal fistula) is associated with an increased risk of 4th degree lacerations (LE3). Crohn's disease without perianal involvement is not associated with an excess risk of OASIS (LE3). For women with type III genital mutilation, deinfibulation before delivery is associated with a reduction in the risk of OASIS (LE3); in this situation, deinfibulation is recommended before delivery (grade C).

CONCLUSION

It is necessary to use a consensus definition of the OASIS to be able to better detect and treat them.

[Cesarean section and perineal protection: CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVE

The endpoint was to assess the interest of planned cesarean section in primary and secondary obstetrical perineal prevention.

METHODS

This is a review of the literature about the impact of the mode of delivery in urinary incontinence (UI), anal incontinence (AI), pelvic organ prolapse (POP), sexual disorders de novo or prior to delivery and history of obstetric anal sphincter injuries (OASI).

RESULTS

The studies about UI, AI and sexual disorders report a potential protective impact of cesarean section but with a possible selection bias and an inadequate comparability of the groups. Randomized trials do not report any protective effect of planned cesarean section for these 3 disorders. The literature about POP reports a higher risk for the women who delivered vaginally but still with a possible selection bias et there is no randomized trial for this outcome. About the secondary prevention of OASI, there is no evidence in the literature for a benefit of a systematic planned cesarean section for all women. For symptomatic women, the mode of delivery has to be discussed individually. In secondary prevention of UI, AI, POP and sexual disorders, there is no evidence in the literature for a benefit of planned cesarean section even if there is a history of surgical procedure for the disorder.

CONCLUSION

Planned cesarean section is not recommended in order to prevent primary or secondary obstetrical perineal disorders except for symptomatic OASI for whom an individual discussion about the mode of delivery is recommended.

Effect of subsequent vaginal delivery on bowel symptoms and anorectal function in women who sustained a previous obstetric anal sphincter injury

Introduction and hypothesis

Our primary objective was to prospectively evaluate anorectal symptoms, anal manometry and endoanal ultrasound (EAUS) in women who followed the recommended mode of subsequent delivery following index obstetric anal sphincter injuries (OASIs) using our unit’s standardised protocol. Our secondary objectives were to evaluate the role of internal anal sphincter defects and also to compare outcomes in a subgroup of symptomatic women with normal anorectal physiology.

Methods

This is a prospective follow-up study of pregnant women with previous OASIs who were counselled regarding subsequent mode of delivery between January 2003 and December 2014. Assessment involved the St Mark’s Incontinence Score (SMIS), anal manometry and EAUS at both antepartum and 3-month postpartum visits. Data were analysed using Wilcoxon and Mann–Whitney U tests.

Results

Three hundred and fifty women attended the perineal clinic over the study period, of whom 122 met the inclusion criteria (99 vaginal delivery [VD], 23 caesarean section). No significant worsening of anorectal symptoms was observed following subsequent delivery in the VD group (p = 0.896), although a reduced squeeze pressure was observed at 3 months postpartum (p < 0.001). There were no new defects on EAUS in either group.

Conclusions

This study showed no significant worsening of bowel symptoms and sphincter integrity apart from lower squeeze pressures at 3 months postpartum in the VD group when our standardised protocol was used to recommend subsequent mode of delivery. In the absence of a randomised study, use of this protocol can aid clinicians in their decision-making.

Modified Ritgen Maneuver in Perineal Protection - Sixty-Year Experience

SUMMARY – The aim is to present the 60-year experience in modified Ritgen maneuver according to perineal injuries. This retrospective clinical observational study (1950-2010) analyzed the impact of modified Ritgen maneuver delivery technique (controlled fetal head deflexion with left hand and synchronous reduction of perineal strain with extended right hand thumb along the right side of the vulva and perineum without pushing) on peripartum perineal tears at the Maternity Ward, Bjelovar General Hospital in Bjelovar, Croatia, divided into five-year intervals. The rate of perineal tear in general was less than 5% until 2000. The rate of perineal tear grade I was very low until 1995, then increased to 8.6% in 2010, yet never exceeding 10%. The rate of perineal tear grade II never exceeded 2%, whereas perineal tear grade III was a sporadic event never exceeding 0.4% of the study material with a single case of grade IV tear. The rate of intact perineum in vaginal deliveries without episiotomy ranged from 96.2% to 100% in the 1950-1960 period, with a decrease to 46% in 2010. The study revealed the modification of Ritgen maneuver described to have resulted in significant reduction of all grades of perineal tear over decades.

[Anal incontinence and obstetrical anal sphincter injuries, epidemiology and prevention]

Our main objectives were to identify risk factors, methods for early diagnosis, and prevention of obstetric anal sphincter injuries (OASIs), using a literature review. The main risk factors for OASIs are nulliparity, instrumental delivery, posterior presentation, median episiotomy, prolonged second phase of labor and fetal macrosomia. Asian origin, short ano-vulvar distance, ligamentous hyperlaxity, lack of expulsion control, non-visualization of the perineum or maneuvers for shoulder dystocia also appear to be risk factors. There is a risk of under-diagnosis of OASIs in the labor ward. Experience of the accoucheur is a protective factor. Secondary prevention is based on the training of birth professionals in recognition and repair of OASIs. Primary prevention of OASIs is based on training in the maneuvers of the second phase of labor; if possible, instrumental extractions should be avoided. Mediolateral episiotomy may have a preventive role in high-risk OASIs deliveries. A robust predictive model is still lacking to allow a selective use of episiotomy.

Postpartum two- and three-dimensional ultrasound evaluation of anal sphincter complex in women with obstetric anal sphincter injury

OBJECTIVE

To compare the sensitivity and specificity of two- (2D) and three- (3D) dimensional transperineal ultrasound (TPUS) and 3D endovaginal ultrasound (EVUS) with the gold standard 3D endoanal ultrasound (EAUS) in detecting residual defects after primary repair of obstetric anal sphincter injuries (OASIS).

METHODS

External (EAS) and internal (IAS) anal sphincters were evaluated by the four ultrasound modalities in women with repaired OASIS. 2D-TPUS was evaluated in real-time, whereas 3D-TPUS, 3D-EVUS and 3D-EAUS volumes were evaluated offline by six blinded readers. The presence/absence of any tear in EAS or IAS was recorded and defects were scored according to the Starck system. Sensitivity, specificity and predictive values were calculated, using 3D-EAUS as reference standard. Inter- and intraobserver analyses were performed for all 3D imaging modalities. Association between patients' symptoms (Wexner score) and ultrasound findings (Starck score) was calculated.

RESULTS

Images from 55 patients were analyzed. Compared with findings on 3D-EAUS, the agreement for EAS evaluation was poor for 3D-EVUS (κ = 0.01), fair for 2D-TPUS (κ = 0.30) and good for 3D-TPUS (κ = 0.73). The agreement for IAS evaluation was moderate for both 3D-EVUS (κ = 0.41) and 2D-TPUS (κ = 0.52) and good for 3D-TPUS (κ = 0.66). Good intraobserver (3D-EAUS, κ = 0.73; 3D-TPUS, κ = 0.78) and interobserver (3D-EAUS, κ = 0.68; 3D-TPUS, κ = 0.60) agreement was reported. Significant association between Starck and Wexner scores was found only for 3D-EAUS (Spearman's rho = 0.277, P = 0.04).

CONCLUSIONS

2D-TPUS and 3D-EVUS are not accurate modalities for the assessment of anal sphincters after repair of OASIS. 3D-TPUS shows good agreement with the gold standard 3D-EAUS and a high sensitivity in detecting residual defects. It, thus, has potential as a screening tool after primary repair of OASIS. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Evidence-Based Update on Treatments of Fecal Incontinence in Women

Fecal incontinence is a highly prevalent and distressing condition that has a negative impact on quality of life. The etiology is often multifactorial, and the evaluation and treatment of this condition can be hindered by a lack of understanding of the mechanisms and currently available treatment options. This article reviews the evidence-based update for the management of fecal incontinence.

Restricted episiotomy use and maternal and neonatal injuries: a retrospective cohort study

PURPOSE

There is relatively little information on episiotomies in the context of restricted episiotomy use. This study sought to examine maternal and neonatal injuries with restricted episiotomy use.

METHODS

We performed a retrospective database analysis of vaginal deliveries at a tertiary care maternity hospital from June 2010 to June 2015. Maternal injuries (third- or fourth-degree lacerations) and neonatal injuries (birth trauma) were identified through the International Classification of Diseases, Ninth Revision, codes. Vaginal deliveries were classified as spontaneous, vacuum-assisted, or forceps-assisted. The associations between episiotomy and maternal and neonatal injuries were examined with stratification by parity, type of vaginal delivery, and type of episiotomy (midline or mediolateral). Adjusted-odds' ratios were calculated for maternal and neonatal injuries using a multiple logistic regression model to adjust for potential confounders.

RESULTS

22,800 deliveries occurred during the study interval involving 23,016 neonates. The episiotomy rate was 6.7 % overall and 22.9 % in operative vaginal deliveries. Episiotomies, both midline and mediolateral, were associated with increased risks of maternal and neonatal injuries regardless of parity (p < 0.0001). Upon stratification by the type of delivery, the association with maternal injury remained only for spontaneous vaginal deliveries (p < 0.0001). Adjusted-odds' ratios demonstrated a continued association between episiotomy and maternal [aOR 1.67 (1.39-2.05)] and neonatal injuries [aOR 1.43 (1.17-1.73)].

CONCLUSION

Episiotomy continues to be associated with increased third- and fourth-degree lacerations with restricted use, particularly in spontaneous vaginal deliveries.

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.

Incidence and Risk Factors of Obstetric Anal Sphincter Injuries after Various Modes of Vaginal Deliveries in Chinese Women

BACKGROUND

Obstetric anal sphincter injuries (OASIS) can cause an adverse impact on women's physical and mental health. There was lack of published data in Chinese population particularly on studying the risk of OASIS for nonrotational outlet forceps. This study was to determine the incidence and risk factors of OASIS.

METHODS

This is a retrospective cohort study carried out in a tertiary referral hospital in Hong Kong. The control group was selected randomly. Univariate and multivariate logistic regression analysis was performed to evaluate the influence of potential risk factors on OASIS. This study reviewed the obstetric records of OASIS women and random control from January 2011 to June 2014. Univariate and multivariate logistic regression analysis was performed to evaluate the influence of potential risk factors on OASIS.

RESULTS

Of 15,446 women delivered, 49 had OASIS. The percentage of OASIS increased from 0.3% (2011) to 0.38% (2014). There was an increasing trend of OASIS in attempted spontaneous vaginal delivery without episiotomy (P < 0.01), but it did not increase the OASIS risk (P = 0.46). Univariate analysis of 49 cases and 438 control subjects showed that forceps delivery (odds ratio [OR] =8.73, P < 0.01), prolong second stage of labor (OR = 1.43, P < 0.01) increased the risk for OASIS. In multivariate regression models, only forceps delivery (OR = 6.28, P < 0.01) proved to be independent risk factor.

CONCLUSIONS

The incidence of OASIS in Chinese women was increased after 2012, but still lower than the reported figures in the literature. Outlet forceps delivery could be a possible associated risk factor.

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.