Obstetric anal sphincter injury rates among primiparous women with different modes of vaginal delivery

Asian-White disparities in obstetric anal sphincter injury: a systematic review and meta-analysis

OBJECTIVE

Obstetrical anal sphincter injury describes a severe injury to the perineum and perianal muscles after birth. Obstetrical anal sphincter injury occurs in approximately 4.4% of vaginal births in the United States; however, racial and ethnic inequities in the incidence of obstetrical anal sphincter injury have been shown in several high-income countries. Specifically, an increased risk of obstetrical anal sphincter injury in individuals who identify as Asian vs those who identify as White has been documented among residents of the United States, Australia, Canada, Western Europe, and the Scandinavian countries. The high rates of obstetrical anal sphincter injury among the Asian diaspora in these countries are higher than obstetrical anal sphincter injury rates reported among Asian populations residing in Asia. A systematic review and meta-analysis of studies in high-income, non-Asian countries was conducted to further evaluate this relationship.

DATA SOURCES

MEDLINE, Ovid, Embase, EmCare, and the Cochrane databases were searched from inception to March 2023 for original research studies.

STUDY ELIGIBILITY CRITERIA

Observational studies using keywords and controlled vocabulary terms related to race, ethnicity and obstetrical anal sphincter injury. All observational studies, including cross-sectional, case-control, and cohort were included. 2 reviewers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Meta-analysis of Observational Studies in Epidemiology recommendations.

METHODS

Meta-analysis was performed using RevMan (version 5.4; Cochrane Collaboration, London, United Kingdom) for dichotomous data using the random effects model and the odds ratios as effect measures with 95% confidence intervals. Subgroup analysis was performed among Asian subgroups. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tools. Meta-regression was used to determine sources of between-study heterogeneity.

Results

A total of 27 studies conducted in 7 countries met the inclusion criteria encompassing 2,337,803 individuals. The pooled incidence of obstetrical anal sphincter injury was higher among Asian individuals than White individuals (pooled odds ratio, 1.64; 95% confidence interval, 1.48-1.80). Subgroup analyses showed that obstetrical anal sphincter injury rates were highest among South Asians and among population-based vs hospital-based studies. Meta-regression showed that moderate heterogeneity remained even after accounting for differences in studies by types of Asian subgroups included, study year, mode of delivery included, and study setting.

Conclusion

Obstetrical anal sphincter injury is more frequent among Asian versus white birthing individuals in multiple high-income, non-Asian countries. Qualitative and quantitative research to elucidate underlying causal mechanisms responsible for this relationship are warranted.

Three-Dimensional Transperineal Ultrasound Guiding Early Secondary Repair of Obstetric Anal Sphincter Injury in an Incontinent Patient without Suture Dehiscence

We present the case of a 36-year-old primigravida who gave birth to a 3200 g baby by vacuum-assisted (Kiwi OmniCup™) operative vaginal delivery with mediolateral episiotomy. A "y"-shaped perineal tear with a grade IIIC obstetric anal sphincter injury (OASI) was diagnosed and repaired. Two days after delivery, in the absence of suture dehiscence, she started experiencing complete anal incontinence. A decision was made in association with a proctologic surgeon for an early secondary repair. Before surgery, a Three-dimensional transperineal ultrasound (TPUS) was performed. The exam revealed a major defect of the external anal sphincter at the 11 o'clock position. This allowed for the reopening of only a circumscribed area of the perineal suture and repair of the sphincters using the end-to-end technique. The symptoms regressed completely, and follow-up TPUS demonstrated the gradual wound healing process. Anal incontinence, secondary to obstetric anal sphincter injury (OASI), has a severe negative impact on women's quality of life. TPUS is an effective method to detect sphincter defects and monitor the healing process. This report investigates the feasibility of identifying the sphincter tear in an incontinent puerperal patient without suture dehiscence in order to target early secondary repair while minimizing its extent. TPUS has proven a safe and effective tool to guide early secondary repair of symptomatic OASI complications while minimizing the invasiveness of the procedure. Multidisciplinary management is crucial to ensure the adequate standard of care.

Level of episiotomy practice and its disparity among primiparous and multiparous women in Ethiopia: a systematic review and meta-analysis

Background

Episiotomy at the time of vaginal birth is a common lifesaving surgical procedure. In Ethiopia, several studies have been conducted concerning the proportion of episiotomy. However, its prevalence varies across these series of studies. Thus, this systematic review and meta-analysis aimed to estimate the level of episiotomy practice and its disparity among primiparous and multiparous women in Ethiopia.

Methods

This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline. We systematically searched the PubMed/MEDLINE, EMBASE, Google Scholar, and Science Direct databases for studies conducted in Ethiopia focusing on episiotomy. We included all cross-sectional studies published until October 5,2022. Data were analyzed using R version 4.2.1 software. The pooled estimates with 95% confidence intervals (CIs) were presented using forest plots. A random-effects meta-analysis was conducted on extracted crude rates to calculate the national and regional pooled estimates for the country. The I-squared test and Egger's regression test were used to assess heterogeneity and publication bias, respectively.

Results

Our search yielded 390 articles. A total of 13 studies covering five administrative regions and 6,404 women who delivered vaginally were involved. The mean age of the study participants ranged from 22 to 27.7 years. The estimated overall pooled prevalence rate of episiotomy in Ethiopian women was 42.75% (95% CI: 34.97%-50.54%). In the subgroup analysis, the pooled prevalence rate of episiotomy was 61.45% (95% CI: 51.11%-71.80%) among primiparous women. Meanwhile, the pooled estimate appears to be approximately 30.47% (95% CI: 22.08%-38.85%) among multiparous women.

Conclusion

Our findings concluded that the pooled prevalence rate of episiotomy was higher than the evidence-based WHO recommendations for optimal patient care. Parallel to this, nulliparous women had a higher episiotomy rate than multiparous women. These findings highlight the importance of continued training for labor ward staff, particularly healthcare providers who often perform the majority of deliveries.

A systematic review and meta-synthesis of qualitative studies on childbirth perineal trauma for the development of a Core Outcome Set

OBJECTIVES

Perineal injury occurs in 85% of cases during vaginal childbirth. This study aimed to synthesize qualitative data on women's perceptions of perineal trauma during vaginal childbirth.

STUDY DESIGN

Thematic synthesis was applied utilizing a structured three-step framework. First, line-by-line coding strategy was applied to the included studies. Secondly, related codes were grouped together to develop descriptive themes to emphasize what matters most for women suffering from childbirth perineal trauma. Thirdly, analytical themes were developed. The quality of the included studies was high based on the assessment using the Critical Appraisal Skills Programme tool.

RESULTS

Ten eligible studies were included in the meta-synthesis. Twenty-three codes encompassing multiple aspects of childbirth trauma from women's perspective were organised into a set of eight descriptive themes: psychosocial effects, communication, recovery, pain, support, knowledge of childbirth perineal trauma, sexuality, and prioritization.

CONCLUSIONS

Among the descriptive themes, psychosocial effects, communication, and recovery exhibited the highest prevalence. The findings of this meta-synthesis may serve as a reporting guideline for future studies investigating the consequences of childbirth perineal trauma, ensuring that women's priorities are accurately reflected in reported outcomes.

Asian-white disparities in obstetric anal sphincter injury: Protocol for a systematic review and meta-analysis

BACKGROUND

Obstetric anal sphincter injury (OASI) describes severe injury to the perineum and perineum and perianal muscles following birth and occurs in 4.4% to 6.0% of vaginal births in Canada. Studies from high-income countries have identified an increased risk of OASI in individuals who identify as Asian race versus those who identify as white. This protocol outlines a systematic review and meta-analysis which aims to determine the incidence of OASI in individuals living in high-income countries who identify as Asian versus those of white race/ethnicity. We hypothesize that the pooled incidence of OASI will be higher in Asian versus white birthing individuals.

METHODS

We will search MEDLINE, OVID, Embase, Emcare and Cochrane databases from inception to 2022 for observational studies using keywords and controlled vocabulary terms related to race, ethnicity and OASI. Two reviewers will follow the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and Meta-analysis of Observational Studies (MOOSE) recommendations. Meta-analysis will be performed using RevMan for dichotomous data using the random effects model and the odds ratio (OR) as effect measure with a 95% confidence interval (CI). Subgroup analysis will be performed based on Asian subgroups (e.g., South Asian, Filipino, Chinese, Japanese individuals). Study quality assessment will be performed using The Joanna Briggs Institute Critical Appraisal tools.

DISCUSSION

The systematic review and meta-analysis that this protocol outlines will synthesize the extant literature to better estimate the rates of OASI in Asian and white populations in non-Asian, high-income settings and the relative risk of OASI between these two groups. This systematic summary of the evidence will inform the discrepancy in health outcomes experienced by Asian and white birthing individuals. If these findings suggest a disproportionate burden among Asians, they will be used to advocate for future studies to explore the causal mechanisms underlying this relationship, such as differential care provision, barriers to accessing care, and social and institutional racism. Ultimately, the findings of this review can be used to frame obstetric care guidelines and inform healthcare practices to ensure care that is equitable and accessible to diverse populations.

Is there an Association between Vaginal Birth after Cesarean Prediction and Obstetric Anal Sphincter Injury?

OBJECTIVE

This study aimed to estimate whether there is an association between the predicted probability of vaginal birth after cesarean delivery (VBAC) and the occurrence of obstetric anal sphincter injuries (OASIS).

STUDY DESIGN

This was a single-site retrospective cohort study of all women with a singleton vaginal birth after a previous cesarean section between January 2011 and December 2016. Women were divided into four ordinal groupings by the predicted probability of achieving vaginal birth after cesarean using the Maternal-Fetal Medicine Units Network VBAC calculator (less than 41%, 40.1-60%, 60.1-80%, and greater than 80%). The primary outcome was OASIS, defined as a 3rd or 4th degree perineal laceration. Bivariable and multivariable analyses were used to examine the association between predicted VBAC probability and OASIS.

RESULTS

In total, 1,411 women met inclusion criteria and 73 (5.2%) sustained OASIS. The median predicted probability of VBAC was lower in women with OASIS compared with those without OASIS (60% [interquartile range {IQR}: 48-70%] vs. 66% (IQR: 52-80%), p = 0.02]. On bivariable and multivariable logistic regression, predicted probability of VBAC was associated with increased odds of OASIS (less than 41% probability: adjusted odds ratio [aOR]: 3.18, 95% confidence interval [CI]: 0.90-11.21; 41-60% probability: aOR: 3.76, 95% CI: 1.34-10.57; 61-80% probability aOR: 3.47, 95% CI: 1.25-9.69) relative to women with a predicted probability of VBAC of greater than 80%.

CONCLUSION

Having a lower predicted probability of VBAC is associated with an increased risk of OASIS at the time of a VBAC relative to those with greater than 80% predicted probability. Incorporation of this aspect of maternal morbidity may inform risk-stratification at the time of trial of labor after cesarean, as well as the choice of performing an operative vaginal delivery.

KEY POINTS

· Predicted probability of VBAC is associated with OASIS.. · Low predicted probability of VBAC is associated with increased odds of OASIS.. · Forceps delivery was associated with the highest odds of OASIS..

Women's experiences of the OASI Care Bundle; a package of care to reduce severe perineal trauma

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injury (OASI) is a severe form of perineal trauma that can occur during vaginal birth. Long-term morbidities include anal incontinence and psychosocial disorders. To reduce these injuries within England, Scotland and Wales, the OASI Care Bundle was introduced to 16 maternity units (January 2017-March 2018). The OASI Care Bundle comprises four elements: (1) antenatal information, (2) manual perineal protection, (3) medio-lateral episiotomy (when indicated) and 4) recognition and diagnosis of tears. As part of the project evaluation, a qualitative study was conducted to explore women's experiences of the OASI Care Bundle.

METHODS

Semi-structured interviews were conducted with women (n = 19) who received the OASI Care Bundle as part of their maternity care. This was to explore their experience of each element. A thematic analysis of the interview data was performed.

RESULTS

Three themes were identified: (1) memories of touch, whereby women reported that a 'hands-on' approach to perineal protection was a positive experience; (2) midwife as a supportive guide, where women reported that good communication facilitated a calm birth and post-birth diagnosis; (3) education: women need more information about perineal trauma.

CONCLUSION

This study contributes to the literature through its exploration of women's experiences of perineal protection techniques and diagnosis of perineal trauma. Interviewed women indicated that they did not experience any of the care bundle elements as an intrusion of their physical integrity. Additionally, an urgent need was identified for more information about perineal trauma in terms of risk, prevention and recovery.

Temporal trends in the incidence of and associations between the risk factors for obstetrical anal sphincter injuries

BACKGROUND

Obstetrical anal sphincter injuries are an important complication of vaginal deliveries that may result in short- and long-term pelvic floor morbidity and a diminished quality of life in young, healthy women. The prevalence of obstetrical anal sphincter injuries ranges from 0.1% to 8.7%. Over recent years, there seems to be a trend of increasing occurrence of obstetrical anal sphincter injuries worldwide. It is unclear why the rates are rising. Previous studies have examined the effect of different risk factors on the prevalence of obstetrical anal sphincter injuries. The change in the incidence of some risk factors for obstetrical anal sphincter injuries can partially explain the overall increase in obstetrical anal sphincter injuries. There is no previous study that explored the impact of the changes of individual risk factors over time on the risk for obstetrical anal sphincter injuries.

OBJECTIVE

The main aim of this study was to examine the temporal trends in the prevalence and odds ratio of the major risk factors known to be associated with obstetrical anal sphincter injuries in the period from 1988 to 2016.

STUDY DESIGN

This was a retrospective cohort study that included all women who underwent vaginal deliveries between 1988 and 2016 at a tertiary university medical center. The time intervals were divided into 4 periods (1988-1997, 1998-2007, 2008-2016, and the total time from 1988 to 2016) and the incidence of each risk factor was calculated for each time period. Correlation models and regression analysis were performed to examine the association between obstetrical anal sphincter injuries and the different risk factors over time. Furthermore, the trends in the odds ratios of the important risk factors over the time periods were evaluated using a multivariate regression analysis in which the primiparous women were separated from the multiparous women.

RESULTS

During the study period, there were 295,668 vaginal deliveries. Of these, 591 women were diagnosed with obstetrical anal sphincter injuries (0.2%). The significant risk factors for obstetrical anal sphincter injuries (P<.05) in the multivariable analysis were the following: primiparity, vaginal birth after cesarean delivery, vacuum extraction, and a birthweight of >4 kg. There was a significant (P<.05) increase in the incidence over the study period for the following risk factors: primiparity, vaginal birth after cesarean delivery, and vacuum extraction. No change was found in the incidence of the risk factor of a birthweight of >4 kg. In addition, we found a strengthening of the association between vaginal birth after cesarean delivery and macrosomia with obstetrical anal sphincter injuries, as opposed to a decline in the relative contribution of vacuum extraction to the overall risk for obstetrical anal sphincter injuries. Moreover, we found that obstetrical anal sphincter injuries among primiparous women increased 7-fold over the study period but was unchanged among multiparous women.

CONCLUSION

We have shown significant (P<.05) temporal trends in the incidence and odds ratio of some of the known risk factors for obstetrical anal sphincter injuries. A better understanding of the changes in the incidence and specific contribution of important risk factors for obstetrical anal sphincter injuries may explain, in part, the worldwide increase in the prevalence of this important and detrimental complication of vaginal birth.

Exploring clinicians' perspectives on the 'Obstetric Anal Sphincter Injury Care Bundle' national quality improvement programme: a qualitative study

INTRODUCTION

Obstetric anal sphincter injuries (OASI) can have severe debilitating consequences to women and health systems. The OASI Care Bundle quality improvement programme was introduced in 16 maternity units across England, Scotland and Wales (January 2017 to March 2018) to address increasing OASI rates.

OBJECTIVES

To explore clinicians' (midwives' and obstetricians') perspectives of the OASI Care Bundle with respect to (1) acceptability, (2) feasibility, and (3) sustainability.

DESIGN

A qualitative exploratory study using focus groups methodology.

SETTING

A total of 16 focus groups were conducted in 16 maternity units in England, Scotland and Wales where the OASI Care Bundle was implemented. Focus groups took place approximately 3 months following initial implementation of the care bundle in each unit.

PARTICIPANTS

A total of 101 clinicians participated, with an average of six per focus group. Participants volunteered to take part and compromised of 37 obstetricians and 64 midwives (including eight students). The majority were female and the mean age was 36.5 years.

RESULTS

Four main themes emerged: 'Implementation strategies', 'Opportunities to use the OASI Care Bundle', 'Does current practice need to change?' and 'Perceptions of what women want'. Midwives were more likely than obstetricians to report themes alluding to 'what women want' and variations in intrapartum perineal protection techniques. Both professional groups reported similar views of other themes, in particular regarding the supporting clinical evidence. Gaps were identified in clinicians' knowledge and experience of intrapartum perineal management.

CONCLUSIONS

Adoption of the OASI Care Bundle was associated with a number of cognitive and interpersonal factors, such as personal values, interprofessional working and how the intervention was launched; which both facilitated and impeded adoption. The 'what women want' theme has implications for maternal autonomy and needs further exploration. Our findings can be used by similar initiatives to reduce perineal trauma both nationally and internationally.

TRIAL REGISTRATION NUMBER

ISCTRN 12143325; https://doi.org/10.1186/ISRCTN12143325.

Obstetric anal sphicnter injury in a Spanish hospital

OBJECTIVE

Estimation of the prevalence of obstetric anal sphincter injury (OASIS) in our environment and study of the associated risk factors.

STUDY DESING

A retrospective observational study of cases and controls of assisted deliveries at the Severo Ochoa University Hospital of Leganés during the period from January 1, 2012, to December 31, 2017. A total of 88 OASIS diagnosed in the study period is compared with a randomly selected group of 181 controls of similar characteristics, vaginal births of cephalic of 36 weeks gestation or more, occurring during the same period.

RESULTS

During the study period, a total of 8160 deliveries were attended in our hospital, of which 6187 were vaginal and we diagnosed a total of 88 OASIS at the time of delivery. The prevalence of OASIS is 1.07 % for total births and 1.42 % for total vaginal deliveries. In the case-control study, the univariate analysis shows statistical significance for nulliparity (OR 3.84; 95 % CI 2.155-6.834; p < 0.001), instrumental delivery (OR 8.73; 95 % CI 4.706-16.2016; p < 0.001), occipital posterior position (OR 7.23; 95 % CI 2.535-20.633; p < 0.001), long duration of the second stage of labor (OR 1.99; IC95 % 1,159-3,438; p 0.01), episiotomy (OR 3.51; 95 % CI 1,956-6,309; p < 0.001) and OBGYN labor assistant (<0.001). When performing the multivariate analysis, forceps delivery (OR19.68), Thierry spatulas delivery (OR 8.15), vacuum delivery (OR 2.74), nulliparity (OR 2.56) and fetal weight in grams (OR 1.12) remain significant in the final model.

CONCLUSION

The main risk factors for the onset of OASIS are instrumental delivery, nulliparity and fetal birth weight.

Impact of a quality improvement project to reduce the rate of obstetric anal sphincter injury: a multicentre study with a stepped-wedge design

Objective

To evaluate the impact of a care bundle (antenatal information to women, manual perineal protection and mediolateral episiotomy when indicated) on obstetric anal sphincter injury (OASI) rates.

Design

Multicentre stepped‐wedge cluster design.

Setting

Sixteen maternity units located in four regions across England, Scotland and Wales.

Population

Women with singleton live births between October 2016 and March 2018.

Methods

Stepwise region by region roll‐out every 3 months starting January 2017. The four maternity units in a region started at the same time. Multi‐level logistic regression was used to estimate the impact of the care bundle, adjusting for time trend and case‐mix factors (age, ethnicity, body mass index, parity, birthweight and mode of birth).

Main outcome measures

Obstetric anal sphincter injury in singleton live vaginal births.

Results

A total of 55 060 singleton live vaginal births were included (79% spontaneous and 21% operative). Median maternal age was 30 years (interquartile range 26–34 years) and 46% of women were primiparous. The OASI rate decreased from 3.3% before to 3.0% after care bundle implementation (adjusted odds ratio 0.80, 95% CI 0.65–0.98, P = 0.03). There was no evidence that the effect of the care bundle differed according to parity (P = 0.77) or mode of birth (P = 0.31). There were no significant changes in caesarean section (P = 0.19) or episiotomy rates (P = 0.16) during the study period.

Conclusions

The implementation of this care bundle reduced OASI rates without affecting caesarean section rates or episiotomy use. These findings demonstrate its potential for reducing perineal trauma during childbirth.

Tweetable abstract

OASI Care Bundle reduced severe perineal tear rates without affecting caesarean section rates or episiotomy use.

OASI Care Bundle reduced severe perineal tear rates without affecting caesarean section rates or episiotomy use.

Anal incontinence and unrecognized anal sphincter injuries after vaginal delivery- a cross-sectional study in Norway

Background

Aim of the study was to estimate the prevalence of postpartum anal incontinence among women who delivered vaginally, and to assess the extent to which obstetric injuries to the anal sphincters are missed.

Methods

All women (both primiparous and multiparous) who delivered vaginally and received any kind of sutures in the perineal area at Innlandet Hospital Trust Elverum in Norway between January 1, 2015 and June 30, 2016 were invited to answer a questionnaire on St. Mark’s incontinence score and to participate in a clinical examination of the pelvic floor including endoanal sonography.

Results

In total 52,3% (n = 207) of the 396 invited women participated in the study. Mean St. Mark’s score was 1.8 points (95% CI 1.4 to 2.1) at examination 14 months (mean) postpartum, and none of the participants suffered from weekly fecal leakage. Fecal urgency affected 11.7% (95% CI 7.1 to 16.3) of the participants, and 8.7% (95%CI 5.1 to 12.8) had weekly involuntary leakage of flatus. Nine women (9.3%, 95% CI 4.1 to 15.5) had a previously undetected third degree obstetric anal sphincter injury.

Conclusion

The prevalence of anal incontinence among women who have delivered vaginally and received sutures due to 1st and 2nd degree perineal lacerations is low. Some obstetric anal sphincter injuries remain unrecognized at the time of delivery, but the symptoms of anal incontinence due to these injuries are in the lower half of the St. Mark’s incontinence score. Women with persistent symptoms like fecal urgency or leakage of gas and/or feces should be referred to evaluation by a colorectal surgeon in order to achieve optimal treatment.

Long-term outcome of sphincteroplasty with separate suturing of the internal and the external anal sphincter

Background

Sphincteroplasty is one of the treatment options for anal incontinence following obstetric injury. The aim of the study was to evaluate the long-term effect of sphincteroplasty with separate suturing of the internal and the external anal sphincter on anal continence.

Methods

A retrospective study was conducted on women who had sphincteroplasty for treatment of anal incontinence following obstetric injury. Women operated between January 1, 2011 and December 31, 2014 at Sykehuset Innlandet Hospital Trust Hamar, were invited to answer a questionnaire and participate in a clinical examination, including endoanal sonography.

Results

111 (86.7%) women participated. Median postoperative follow-up was 44.5 months, and 63.8% of the participants experienced an improvement of at least three points in the St. Mark’s incontinence score. Fecal urgency and daily fecal leakage persisted in 39.4% and 6.4% of the participants, respectively. The internal anal sphincter improvement persisted in 61.8% of the participants, and there was a median reduction of their St. Mark’s score of 6.0 points between the preoperative value and the value at long-term follow-up. There was no significant change in the St. Mark’s score of patients with persistent dehiscence of the internal anal sphincter.

Conclusions

Sphincteroplasty, with separate suturing of the internal sphincter resulted in continence for stool maintained for at least 3 years in the majority of the patients, while there was an improvement in continence in nearly two-thirds.

A novel classification for evaluating episiotomy practices: application to the Burgundy perinatal network

Background

Though the rate of episiotomy has decreased in France, the overall episiotomy rate was 20% in the 2016 national perinatal survey. We aimed to develop a classification to facilitate the analysis of episiotomy practices and to evaluate whether episiotomy is associated with a reduction in the rate of obstetric anal sphincter injuries (OASIS) for each subgroup.

Methods

This population-based study included all the deliveries that occurred in the Burgundy Perinatal Network from 2011 to 2016. The main outcome was episiotomy, which was identified thanks to the French Common Classification of Medical Procedures. An ascending hierarchical cluster analysis was performed to build the classification. A clinical audit using the classification was conducted yearly in all obstetric units. The episiotomy rates were described throughout the study period for each subgroup of the classification. The OASIS rates were evaluated by subgroup and the association between mediolateral episiotomy and OASIS was investigated for each subgroup.

Results

Our analyses included 81,290 pregnant women. The classification comprised 7 subgroups: ₍₁₎ nulliparous single cephalic at term, ₍₂₎ nulliparous single cephalic at term with instrumental delivery, ₍₃₎ multiparous single cephalic at term, ₍₄₎ multiparous single cephalic at term with instrumental delivery, ₍₅₎ all preterm deliveries (< 37 weeks gestation), ₍₆₎ all breech deliveries, ₍₇₎ all multiple deliveries.

Episiotomy rates ranged from 6.2% in Group 3 to 40.9% in Group 2. From 2011 to 2016, every group except breech deliveries experienced a significant decrease in episiotomy rates, ranging from − 28.1 to − 61.0%.

The prevalence of OASIS was the highest in Groups 2 (3.0%) and 4 (2.2%). Overall OASIS rates did not significantly differ with episiotomy use (P = 0.25). However, we found that the use of episiotomy was associated with a reduction in OASIS rates in Groups 1 and 2 (odds ratio 0.6 [95% CI 0.4–0.9] and 0.4 [0.3–0.5], respectively). This reduction was only observed in Group 4 with forceps delivery (odds ratio 0.4 [0.1–0.9]).

Conclusion

We developed the first classification for the evaluation of episiotomy practices based on 7 clinically relevant subgroups. This easy-to-use tool can help obstetricians and midwives improve their practices through self-assessment.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2424-2) contains supplementary material, which is available to authorized users.

Anatomic and functional evaluation of the levator ani muscle after an obstetric anal sphincter injury

PURPOSE

To study the relationship between symptoms of anal incontinence (AI) and the anatomy and functionality of the levator ani muscle in women with a history of obstetric anal sphincter injury (OASI).

METHODS

This is a cohort study including patients with OASI from 2013 to 2016. Patients were assessed by a physical examination, endoanal ultrasound using Starck Scale, perineometry and 4D transperineal ultrasound. AI in all patients was measured with the Wexner scale. Correlation between variables has been analyzed in these patients.

RESULTS

72 patients were analyzed: 28 with a IIIA degree tear, 26 with a IIIB, 13 with a IIIC and 5 with a IV. 38 patients showed a residual anal sphincter (AS) defect on endoanal ultrasound with an average Starck score of 6.5 ± 3.7. 21 patients expressed AI, with an average Wexner score of 4.1 ± 2.4. In 27 (37.5%) patients, a levator ani avulsion was observed: 17 unilateral and 10 bilateral. Patients with a levator ani defect had weaker pelvic floor muscle (PFM) function. These differences were statistically significant with perineometry (p = 0.01 and p = 0.03) but not for the Oxford test (p = 0.08). Patients with a residual AS defect as well as an injury to the levator ani muscle expressed greater AI symptomatology than patients with residual sphincter injury who maintain the integrity of the levator ani: Wexner 4.9 0.9 vs 3.3 1 (p = 0.02).

CONCLUSIONS

The PFM has correlation with AI symptom development in patients with a history of OASI. Therefore, we suggest a key role of anatomical and functional assessments of the levator ani muscle in these patients.

Anal sphincter injury associated with shoulder dystocia

Objective: Shoulder dystocia is an obstetric emergency, occurring in 0.2-3% of vaginal deliveries. Research has mainly focused on the neonatal morbidity arising from shoulder dystocia, such as brachial plexus injury and hypoxic-ischemic encephalopathy. Maternal morbidity is thought to be increased with shoulder dystocia though is much less commonly reported. Obstetric anal sphincter injury remains the leading cause of fecal incontinence in women and shares several antenatal and intrapartum risk factors with shoulder dystocia. The aim of this study was to identify risk factors for sphincter injury associated with shoulder dystocia.Methods: This retrospective analysis included all cases of shoulder dystocia from 2008 to 2017 in a single unit in North-East Ireland. Maternal characteristics and delivery outcomes were analyzed. Two groups were compared, those with and without anal sphincter injury in our shoulder dystocia cohort and those with and without shoulder dystocia, regardless of sphincter injury. Univariate and multivariate logistic regression models were used to examine risk factors for sphincter injury.Results: There were 24,159 singleton cephalic vaginal deliveries over the study period, with 495 cases of shoulder dystocia, giving an incidence of 2.1% (495/24 159). The rate of anal sphincter injury in those with shoulder dystocia was 4.4% (22/495), with 7.6% (12/158) in nulliparas, and 3.0% (10/337) among multiparas. Women with sphincter damage were more likely to be nulliparous than those with an intact sphincter (54.5% [12/22] vs. 30.9% [146/473]; p = .036) and have an operative vaginal delivery (72.7% [16/22] vs. 39.1% [185/473]; p = .004). Episiotomy was more common in those with a sphincter injury (68.2% [15/22] vs. 37.0% [175/473]; p = .007). On univariate regression analysis, nulliparity (OR 2.69) and operative vaginal delivery (OR 4.15) were associated with sphincter injury. No risk factors were identified on multivariate regression analysis.Discussion: In our population, the risk of anal sphincter injury with shoulder dystocia is 4.4%. Risk factors include nulliparity and operative vaginal delivery. After controlling for other factors, these associations became nonsignificant. Further research into sphincter injury at shoulder dystocia is warranted.

Risk and protective factors for obstetric anal sphincter injuries: A retrospective nationwide study

BACKGROUND

In view of the reported increase in obstetric anal sphincter injuries, the objective of this study was to evaluate the incidence of such injuries over time and the associated risk and protective factors.

METHODS

This was a retrospective cohort study from a national database of 168 137 primiparous women with term, singleton, cephalic, vaginal delivery between 2008 and 2014. The main outcome measure was obstetric anal sphincter injury. A multivariate regression model was used to identify risk and protective factors.

RESULTS

Age >19 years, birthweight >4000 g, and operative vaginal delivery were independent risk factors for obstetric anal sphincter injuries. Mediolateral episiotomy increased the risk for obstetric anal sphincter injuries in spontaneous vaginal birth (number needed to harm 333), whereas it was protective in vacuum delivery (number needed to treat 50). From 2008 to 2014, there was an increase in the rate of obstetric anal sphincter injuries (2.1% vs 3.1%, P < .01), vacuum deliveries (12.1% vs 12.8%, P < .01), and cesarean delivery after labor (17.1% vs 19.4%, P < .01), while forceps deliveries (0.4% vs 0.1%, P < .01) and episiotomy rate decreased (35.9% vs 26.4%, P < .01).

CONCLUSIONS

Episiotomy may be a risk or protective factor depending on the type of episiotomy and the clinical setting in which it is used. Our study supports a restrictive use of mediolateral episiotomy in spontaneous vaginal deliveries. In vacuum deliveries mediolateral episiotomy may help prevent obstetric anal sphincter injuries.

[Obstetrical anal sphincter injuries and vacuum-assisted delivery at term in primiparas]

OBJECTIVES

Operative Vaginal Delivery (OVD) is subject to a risk of perineal tears especially of Obstetrical Anal Sphincter Injuries (OASIS) that are associated with more complications and impaired quality of life. The main objective of this study was to compare the rate of OASIS in primipara at term with fetus in cephalic presentation depending on the type of delivery: OVD using vacuum extractor and spontaneous delivery.

METHODS

This is a single-center retrospective study between 01/01/2010 and 12/31/2014 including all primipara who delivered vaginally at term, a single and living fetus in cephalic presentation. Perineal lesions were classified according to the WHO classification. The primary endpoint was the proportion of OASIS.

RESULTS

3552 patients were included: 2496 spontaneous deliveries (SD) and 1056 OVD (29.72 %). There were twenty sphincter tears (0.56 %): 7 in SD group (0.28 %) and 13 in OVD (1.23 %), P<0.0001, OR=5.10 [2.00; 12.99]. Other risk factors associated with OASIS in univariable analysis were: maternal age (≥30 years), duration of expulsive efforts (≥20min) and a birth weight≥4000g.

CONCLUSION

In these patients, the risk of OASIS in case of AI increases by a factor of 5;10. The high rate of AI in these patients exposes them to a real risk of OASIS. However, the proportion of OASIS in this group remains lower than those reported in the literature and is barely higher than the national overall rate, despite a very restrictive policy of the use of episiotomy.

Risk factors for obstetric anal sphincter injuries (OASIS) during vacuum extraction delivery in a university affiliated maternity hospital

Introduction: Instrumental delivery is a well-known risk factor for obstetric anal sphincter injuries (OASIS). The specific characteristics among patient undergoing vacuum extraction delivery (VE) are less studied. Therefore, we aimed to evaluate risk factors for OASIS among parturient that underwent a VE delivery in a large university affiliated maternity hospital.Material and methods: The study population contained 9116 women who delivered by VE in tertiary medical center from 1988 to 2015. Inclusion criteria included deliveries beyond 24-week gestation. Multiple gestations and pregnancies complicated with stillbirth were excluded from the analysis. Maternal obstetric variables were compared between parturient with and without OASIS. Independent risk factors for OASIS were assessed by multivariable logistic regression modeling.Results: OASIS was diagnosed in 94 women (1.03%) following vacuum extraction. Among patients who underwent a VE delivery, gravidity and parity were found to be significantly lower in patients with OASIS. A multivariable logistic regression model with OASIS as the outcome variable revealed that among women who underwent VE, while episiotomy and delivery of a macrosomic neonate were not independently associated with OASIS, a strong association between nulliparity and OASIS was found (OR 3.34; 95% CI 1.93-5.78; p < .001).Conclusions: OASIS is uncommon in our population. Vacuum extraction in nulliparous parturient is a significant risk factor for OASIS. Our results should be taken into account when managing nulliparous deliveries.

A multi-centre quality improvement project to reduce the incidence of obstetric anal sphincter injury (OASI): study protocol

BACKGROUND

Third and fourth degree perineal tears, or obstetric anal sphincter injuries (OASI), sustained during childbirth can result in anal incontinence and psychosocial problems which require ongoing treatment. Within the English National Health System (NHS) reported rates of OASI have gradually increased. In response, a care bundle was developed incorporating four elements: 1) antenatal information to women, 2) manual perineal protection during all vaginal births, 3) episiotomy to be performed with a 60° mediolateral angle at crowning (when clinically indicated) and 4) perineal examination (including per rectum) after childbirth. Implementation of the OASI Care Bundle is aided by a skills development module and an awareness campaign. The project is a collaboration between two national professional bodies, an NHS hospital trust and an academic institution.

METHODS

Implementation of the OASI Care Bundle will be evaluated using a stepped-wedge design. From January 2017 sixteen maternity units across England, Wales and Scotland will participate in the study over a 15-month period, with sequential roll-out of the intervention in four blocks (regions) of four units. The primary clinical outcome is OASI rate. Regression analysis will adjust for differences in organisational characteristics and obstetric risk factors in women who gave birth before and after implementation of the care bundle. Focus group discussions and in-depth interviews with clinicians will evaluate the feasibility of integrating the care bundle into routine practice. Interviews with women will explore the acceptability of the intervention.

DISCUSSION

This protocol outlines the evaluation of our quality improvement project which aims to prevent OASI using a bundle of evidence-based interventions that are each widely used in practice. The OASI project aims to 1) standardise practice to prevent OASI in a way that is acceptable to clinicians and women and 2) identify the barriers and enablers associated with upscaling interventions within maternity units. If found to be effective, feasible and acceptable, the OASI Care Bundle will be shared with a range of audiences using the communication channels available to the professional bodies.

TRIAL REGISTRATION

The OASI Project was retrospectively registered on the ISCTRN12143325 database date assigned 03/10/2017.

Factors associated with obstetric anal sphincter injuries in midwife-led birth: A cross sectional study

INTRODUCTION

Obstetric anal sphincter injurie (OASI) in vaginal births are a serious complication, and are associated with maternal morbidity. Focus on modifiable factors in midwives clinical skills and competences contributing to prevent the occurrence of OASI are essential. The objective of this study was to investigate the association between OASI and factors related to midwife-led birth such as manual support of perineum, active delivery of baby's shoulders, maternal birth position, and pushing and breathing techniques in second stage of labour.

METHODS

A prospective cross sectional study including primiparous (n = 129) and multiparous (n = 628) women in midwife-led non-instrumental deliveries with OASI (n = 96) or intact perineum (n = 661). Data were collected in a university hospital in Norway with two different birth settings: an alongside midwife-led unit with approximately 1500 births per year and an obstetrical unit with approximately 3500 births per year. In midwife-led births, there were a total of 2.6% OASI and 18.9% intact perineum.

RESULTS

The sample consisted of 757 women, 12.7% suffered OASI and 87.3% of participating women had an intact perineum. This selected sample compares the most serious outcome (OASI), and the optimal outcome (intact perineum).In primiparous women, 61 women suffered OASI and 68 women had intact perineum, while for multipara women, 35 women suffered OASI and 593 women had intact perineum. There was an increased risk of OASI if women actively pushed when the head was crowning compared to breathing the head out (adjusted OR: 3.10; 95% CI: 1.75 to 5.47). The maternal birth position associated with the lowest risk of OASI was kneeling position (adjusted OR: 0.15; 95% CI: 0.03 to 0.70), supine maternal birth position (adjusted OR: 2.52; 95% CI: 1.04 to 4.90) and oxytocin augmentation more than 30 min in second stage (OR: 1.93; 95% CI: 1.68 to 15.63) were associated with an increased risk of OASI, when adjusting for maternal, foetal, and obstetric factors.

CONCLUSION

Our study suggests that actively pushing when the baby's head is crowning, a supine maternal birth position and oxytocin augmentation more than 30 min in second stage, were associated with increased risk of OASI when compared to intact perineum. A kneeling maternal birth position was associated with a decreased risk of OASI.

Outcomes of primary anal sphincter repair after obstetric injury and evaluation of a novel three-choice assessment

Background

The aim of the present study was to evaluate the subjective outcome of primary repair of obstetric anal sphincter injury (OASIS) at 6 months, the factors associated with the symptoms of anal incontinence (AI), and the role of a simple survey consisting in one question with three answer choices, combined with the Wexner incontinence score for the assessment of this patient population.

Methods

A retrospective cohort study was conducted on patients with third- or fourth-degree OASIS operated on between January 2007 and December 2013 inclusive at Tampere University Hospital, Finland. At 6 months, the patients were asked to report their Wexner’s score as well as the three-choice assessment regarding AI symptoms. Based on this assessment, the patients were divided into three groups: those, asymptomatic, those with mild symptoms who did not want further treatment and those with severe symptoms who were willing to undergo further evaluation and treatment.

Results

There were 325 patients (median age 30 years). A total of 310 patients answered the questionnaire. Of which, one hundred and ninety-eight (63.9%) patients were asymptomatic, 85 (27.4%) had mild AI, and 27 (8.7%) experienced severe symptoms. There was no statistical difference in the results between the two techniques used (overlapping vs. end-to-end), or the stage of specialization of the operating physician. Persistent symptoms were associated with instrumental vaginal delivery (OR 2.12, 95% CI 1.32–3.41), severity of the injury (OR 1.64, 95% CI 1.20–2.25), and increased maternal age (OR 1.07, 95% CI 1.02–1.13). The correlation between the three-choice symptom evaluation and the Wexner score was good (Spearman’s rho 0.82).

Conclusions

After 6 months, severe symptoms after OASIS repair were present in 9% of women and were more frequent in older women, women with high-degree tears and after instrumental vaginal delivery. A three-choice assessment of AI symptoms correlated well with the Wexner score and might be useful to triage patients who need further evaluation.

Residual defects after repair of obstetric anal sphincter injuries and pelvic floor muscle strength are related to anal incontinence symptoms

INTRODUCTION AND HYPOTHESIS

The aim was to analyze the correlation between residual anal sphincter (AS) defects and pelvic floor muscle (PFM) strength on anal incontinence (AI) in patients with a history of obstetric AS injuries (OASIS).

METHODS

From September 2012 to February 2015, an observational study was conducted on a cohort of females who underwent repair of OASIS intrapartum. The degree of OASIS was scored intrapartum according to Sultan's classification. Participants were assessed at 6 months postpartum. Incontinence symptoms were evaluated using Wexner's score and PFM strength using the Modified Oxford Scale (MOS). 3D-endoanal ultrasound was performed to classify AS defects according to Starck's system. Correlation between Sultan's and Starck's classifications was calculated using Cohen's kappa and Spearman's rho (R_s) test. The impact of residual AS defects and PFM strength on AI was analyzed using a multiple regression model.

RESULTS

A total of 95 women were included in the study. Good correlation (κ= 0.72) was found between Sultan's and Starck's classifications. Significant positive correlation was observed between Wexner's score and both Sultan's (p = 0.023, R_s =0.212) and Starck's (p < 0.001, R_s =0.777) scores. The extent of the residual AS defect was the most relevant factor correlating with AI symptoms. In patients with severe AS injuries, higher MOS values were associated with lower Wexner's score.

CONCLUSIONS

The degree of AS tear measured intrapartum was the most important factor related to AI after primary repair of OASIS. PFM strength was associated with lower incontinence symptoms in the postpartum period.