Obstetric anal sphincter injuries: review of anatomical factors and modifiable second stage interventions

Obstetric Anal Sphincter Injury After Episiometer-Guided Versus Conventional Episiotomy in Instrumental Deliveries: A Randomized Controlled Trial

INTRODUCTION AND HYPOTHESIS

Guidelines recommend episiotomy for instrumental vaginal delivery with an optimal incision angle of 60° to protect the anal sphincter. The "Episiometer" is a new device promising a 60° incision angle. We compared the incidence of obstetric anal sphincter injury (OASI) and post-repair suture angle of episiotomies made with conventional "eyeballing" versus Episiometer guided during instrumental delivery.

METHODS

We conducted this randomized controlled trial in a tertiary care teaching institute in southern India after ethical committee approval, trial registration, and informed consent. We randomized (block) 328 pregnant women aged 18 years and above with term, singleton fetuses delivered by instruments into Episiometer-guided (164) or conventional episiotomy (164) groups (allocation concealed). We compared the OASI (identified clinically) and the suture angle measured from the midline (assessor blinded) in the two groups. We followed up on the subjects at 6 and 12 weeks to assess perineal pain and fecal/flatus incontinence.

RESULTS

The incidence of OASI of 0.61% in the Episiometer group was significantly lower compared with 4.88% in the eyeballing group (Chi-squared = 5.6; p = 0.02; adjusted risk ratio = 5.9; CI 0.7-46.1; p = 0.09). A significantly higher proportion of subjects (59.1%) in the Episometer group had a post-suture angle between 36 and 40° compared with 36.6% in the eyeballing group (Chi-squared = 21.8, p < 0.001). We found no significant difference in the perineal pain or Wexner score during follow-up.

CONCLUSION

The Episiometer-guided episiotomy during instrumental delivery resulted in a significantly higher suture angle and lower obstetric anal sphincter injuries than with conventional eyeballing.

Is epidural analgesia an independent risk factor for OASIS? A population-based cohort study

INTRODUCTION

To evaluate whether epidural analgesia is an independent risk factor for OASIS.

METHODS

A population-based cohort study including all women who delivered by spontaneous vaginal delivery or by instrumental delivery beyond 24 weeks gestation was conducted. Deliveries occurred between 1988 and 2016 at a large university tertiary medical center. Women with multiple gestations and those lacking prenatal care were excluded from the analysis.

RESULTS

During the study period, 252,542 women delivered at the Soroka University Medical Center and met the inclusion criteria. Of these, 583 (0.23%) were diagnosed with OASIS. Women with OASIS were more likely to be younger, nulliparous, with suspected fetal macrosomia, had higher rates of labor induction and vacuum extraction delivery, higher rates of conceiving after infertility treatments, more advanced gestational age at delivery, higher mean birth weight, higher rates of post-partum hemorrhage and need for blood transfusions. Use of epidural analgesia during pregnancy was significantly high among the OASIS group. Rates of episiotomy were not significantly different between the groups. Using a multimodal logistic regression model, after controlling for vacuum delivery, large for gestational age, nulliparity, gestational age, ethnicity, maternal age, induction of labor, fertility treatments, non-reassuring fetal heart rate and non-progressive second stage of labor, epidural analgesia was found to be significantly associated with OASIS.

CONCLUSION

Epidural analgesia was found to be an independent risk factor for OASIS in our population.

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.

Assessment of Perineal Scars on Translabial Pelvic Floor Ultrasound: A Pilot Study

OBJECTIVE

We aimed to describe a method for identifying and evaluating perineal scars using translabial pelvic floor ultrasound. We hypothesized that translabial ultrasound can identify a perineal scar and can differentiate episiotomies from spontaneous tears.

METHODS

This pilot study is a secondary analysis of data obtained in the Epi-No® trial. Perineal integrity was assessed using volumes acquired on pelvic floor muscle contraction according to the method previously described for anal sphincter imaging. A scar was diagnosed if a hypoechoic distortion in the perineum was noted. We postulated that an episiotomy would result in a linear scar visible on four dimensional translabial ultrasound whereas nonlinear scars were considered the result of spontaneous perineal tear of grade 2 or higher. The results of this assessment were compared with data retrieved from electronic medical records.

RESULTS

A scar was identified in 79/120 women (66%): 42 (35%) linear and 37 (31%) nonlinear. Sonographic and clinical diagnosis agreed on the presence or absence of perineal trauma in 66%. Agreement for the type of laceration was 50%.

CONCLUSION

In this retrospective pilot study, a blinded assessment of translabial ultrasound volume data showed agreement between clinical data and sonographic assessment of perineal integrity in 66% and of type of laceration in 50%. More work is needed to optimize the method in assessment of perineal scars to improve its performance before it can be used in clinical audit and research.

High Incidence of Obstetric Anal Sphincter Injuries among Immigrant Women of Asian Ethnicity

(1) Background: Obstetric anal sphincter injuries (OASI) may complicate vaginal deliveries. The aim of the present study was to explore the incidence and clinical characteristics of OASI among Asian women living in a Western country compared to local Caucasian women. (2) Methods: A retrospective cohort study of 380 women diagnosed with OASI, following singleton vaginal deliveries, during a 10-year period (January 2011 to December 2020). Exclusion criteria: age < 18 years, stillbirth, and breech presentation. Demographic, clinical, and obstetrical data were obtained, and a comparison between Asian and Caucasian women was performed. (3) Results: There were 35 cases of OASI among 997 women of Asian ethnicity compared to 345 cases of OASI among 86,250 Caucasian women (3.5% vs. 0.4%, respectively, p < 0.001). Asian women endured a significantly higher rate of fourth-degree OASI (17.1%) even though they bore smaller newborns (3318 g vs. 3501 g, p = 0.004), and birth weights rarely exceeded 3800 g (2.8% vs. 25.8%, p < 0.001). Asian ethnicity was also associated with a significantly higher risk for blood transfusion following OASI and a lower tendency for postpartum follow up. (4) Conclusions: Immigrant women of Asian ethnicity had a nine-fold higher rate of OASI, much higher than previously reported. Furthermore, Asian women had higher rates of fourth-degree OASI.

Perineal stress as a predictor of performing episiotomy in primiparous women: a prospective observational study

Background

Episiotomy is a surgical solution to relieve perineal stress, resulting in an easily repairable incision, in comparison to the risks of serious vaginal trauma during delivery. The midwife typically adopts such a clinical decision, on experience and subjective judgment. However, the association between perineal stress and episiotomy is poorly characterized. Our aim was to identify a threshold value for perineal stress leading to episiotomy, which eventually may be employed as a clinical tool for assessing whether an episiotomy is required or not.

Methods

In total, 245 nulliparous women were investigated for perineal stress during non-instrumental vaginal delivery in Ningbo Women & Children’s Hospital. During the second stage of labor, a flexible membrane stress sensor was placed between the fetal head and perineal wall above the anal fissure. Once the entire fetal head pressed against the sensor, real-time perineal stress was measured, and the peak value was recorded. Cases were divided into non-episiotomy group (n = 173) and episiotomy group (n = 72). The correlations between perineal stress and episiotomy was assessed through logistic regression with adjustment for maternal age, estimated birthweight, duration of second stage of labor, maternal body mass index, and presence of analgesia. Midwives were blinded to all stress measurement values. The predictive value of perineal stress on performing episiotomy was evaluated, together with the ideal cut-off perineal stress value for performing episiotomy. A ROC analysis was also performed.

Results

The episiotomy group had significantly higher levels of perineal stress in comparison to the non-episiotomy group (140.50 ± 16.03 N versus 118.37 ± 19.21 N, p < 0.01). The episiotomy group was linked to significantly higher perineal stress in comparison to the non-episiotomy group (140.50 ± 16.03 VS 118.37 ± 19.21 N, p < 0.01). ROC analysis between perineal stress and episiotomy revealed a high area under the curve (AUC 0.81, 95% CI 0.75–0.86) and a cut-off value for perineal stress of 124.49 N was identified for episiotomy decision.

Conclusion

The level of perineal stress was an independent predictor of performing episiotomy in nulliparous women during non-instrumental vaginal delivery. Perineal stress exceeding 124.49 N was identified as the cut-off prompting midwives to perform episiotomy.

Aspects of Pelvic Floor Protection in Spontaneous Delivery - a Review

The necessity of increasingly addressing aspects of pelvic floor protection, i.e., prevention of the most frequent female pelvic floor disorders, such as urinary incontinence, faecal incontinence and pelvic organ prolapse, is the result of the steadily improving understanding of the association of pregnancy and delivery with the prevalence of these disorders. About a quarter of all women experience one or more such symptoms during their life. Apart from age and weight, pregnancies and births play an important part. While initial discussion of pelvic floor protection often focused very rapidly on the mode of delivery and elective caesarean section as a possible protective intervention, it has become apparent in the last few decades how varied and wide-ranging the options are that can be used to protect against pelvic floor disorders. The mode of delivery as such is "only" one element among numerous other considerations and has diminished markedly in importance. Interprofessionality and interdisciplinarity undoubtedly represent an important development as resulting recommendations must always be incorporated in an overall context that considers mother and child at the same time. Considering the pelvic floor only certainly does not make sense. This review article will analyze in greater detail important pre-, intra- and postpartum aspects that in their entirety can provide insight into the various aspects of pelvic floor protection. The authors regard the following article as an additional basis for discussion on achieving a sustained reduction in the incidence and prevalence of female pelvic floor disorders.

Risk of obstetric anal sphincter injury among women who birth vaginally after a prior caesarean section: A state-wide cohort study

OBJECTIVE

Vaginal birth after caesarean (VBAC) has been suggested to be associated with an increased risk of obstetric anal sphincter injury (compared with primiparous women who birth vaginally). However, prior studies have been small, or used outdated methodology. We set out to validate whether the risk of obstetric anal sphincter injury among women having their first VBAC is greater than that among primiparous women having a vaginal birth.

DESIGN

State-wide retrospective cohort study.

SETTING

Victoria, Australia.

POPULATION

All births (455,000) between 2009-2014.

METHODS

The risk of severe perineal injury between first vaginal birth and first vaginal birth after previous caesarean section was compared, after adjustment for potential confounding variables. Covariates were examined using logistic regression for categorical data and Wilcoxon rank-sum test for continuous data. Missing data were handled using multiple imputation; the analysis was performed using regression adjustment and Stata v16 multiple imputation and teffects suites.

RESULTS

Women having a VBAC (n=5,429) were significantly more likely than primiparous women (n=123,353) to sustain a 3^rd or 4^th degree tear during vaginal birth (7.1 vs 5.7%, p<0.001). After adjustment for mode of birth, body mass index, maternal age, infant birthweight, episiotomy and epidural, there was a 21% increased risk of severe perineal injury (relative risk 1.21 (95%CI 1.07 - 1.38)).

CONCLUSIONS

Women having their first vaginal birth after caesarean section have a significant increased risk of sustaining a 3^rd or 4^th degree tear, compared with primiparous women having a vaginal birth. Patient counselling and professional guidelines should reflect this increased risk.

Injury-associated levator ani muscle and anal sphincter ooedema following vaginal birth: a secondary analysis of the EMRLD study

OBJECTIVE

To determine whether all three components of the levator ani muscle (pubovisceral [= pubococcygeal], puborectal and iliococcygeal) and the external anal sphincter are equally affected by oedema associated with muscle injury after vaginal birth.

DESIGN

Observational cross-sectional study.

SETTING

Michigan Medicine, University of Michigan.

POPULATION

Primiparous women classified as high risk for levator ani muscle injury during childbirth.

METHOD

MRI scans obtained 6-8 weeks postpartum were analysed. Muscle oedema was assessed on axial and coronal fluid-sensitive magnetic resonance (MRI) scans. Presence of oedema was separately determined in each levator ani muscle component and in the external anal sphincter for all subjects. Descriptive statistics and correlation with obstetric variables were obtained.

MAIN OUTCOME MEASURES

Oedema score on fluid-sensitive MRI scans.

RESULTS

Of the 78 women included in this cohort, 51.3% (n = 40/78) showed muscle oedema in the pubovisceral (one bilateral avulsion excluded), 5.1% (n = 4/78) in the puborectal and 5.1% (n = 4/78) in the iliococcygeal muscle. No subject showed definite oedema on external anal sphincter. Incidence of oedema on the pubovisceral muscle was seven times higher than on any of the other analysed muscles (all paired comparisons, P < 0.001).

CONCLUSIONS

Even in the absence of muscle tearing, the pubovisceral muscle shows by far the highest incidence of injury, establishing that levator components are not equally affected by childbirth. External anal sphincter did not show oedema-even in women with sphincter laceration- suggesting a different injury mechanism. Developing a databased map of injured areas helps understand injury mechanisms that can guide us in honing research on treatment and prevention.

TWEETABLE ABSTRACT

Injury-associated levator ani muscle and anal sphincter oedema mapping on MRI reveals vulnerable muscle components after childbirth.

Prevalence of Perineal Tear Peripartum after Two Antepartum Perineal Massage Techniques: A Non-Randomised Controlled Trial

Perineal massage increases elasticity of myofascial perineal tissue and decreases the burning and perineal pain during labour, thus optimising child birth, although an application protocol has not been standardised yet. The objective of this study is to determine the efficiency of massage in perineal tear prevention and identification of possible differences in massage application. Total of 90 pregnant participants were divided into three groups: perineal massage and EPI-NO^® device group, applied by an expert physiotherapist, self-massage group, where women were instructed to apply perineal massage in domestic household, and a control group, which received ordinary obstetric attention. Results: The results showed significant differences among the control group and the two perineal massage groups in perineal postpartum pain. Correlations in perineal postpartum pain, labour duration and the baby's weight were not statistically significant. Lithotomy posture was significantly less prevalent in the massage group than in the other two; this variable is known to have a direct effect on episiotomy incidence and could act as a causal covariate of the different incidence of episiotomy in the groups. Perineal massage reduces postpartum perineal pain, prevalence and severity of perineal tear during delivery.

Diagnosis and Treatment of Obstetric Anal Sphincter Injuries: New Evidence and Perspectives

Perineal injury during childbirth is a common event with important morbidity associated in particular with third-and-fourth degree perineal tears (also referred to as obstetric anal sphincter injuries-OASIS). Early diagnosis of these damages is mandatory to define a prompt therapeutic strategy and thus avoid the development of late-onset consequences, such as faecal incontinence. For this purpose, various diagnostic exams can be performed after a thorough clinical examination. The management of OASIS includes several measures and should be individualized according to the timing and features of the clinical presentation.

Obstetric anal sphincter injury after episiotomy in vacuum extraction: an epidemiological study using an emulated randomised trial approach

OBJECTIVE

To emulate a randomised controlled trial investigating whether lateral or mediolateral episiotomy compared with no episiotomy reduces the prevalence of obstetric anal sphincter injury (OASIS) in nulliparous women delivered with vacuum extraction.

DESIGN

A population-based observational study.

SETTING

Sweden.

POPULATION

63 654 nulliparous women delivered with vacuum extraction derived from the Swedish Medical Birth Register 2000-2011, with a live singleton baby with no known malformations in cephalic presentation in gestational week ≥34⁺⁰ , and subject to lateral or mediolateral episiotomy or no episiotomy.

METHODS

The effect of episiotomy was calculated using a causal doubly robust estimation method based on propensity scores. Results are presented as the average treatment effect and numbers needed to treat (NNT).

MAIN OUTCOME MEASURES

OASIS (third- and fourth-degree perineal injury) in nulliparous women delivered with vacuum extraction.

RESULTS

Episiotomy was associated with a reduction in OASIS from 15.5% to 11.8%, average treatment effect of -3.66% (95% CI -4.31 to -3.01) and NNT 27. Third-degree perineal injuries were reduced from 14.0% to 10.9% (-3.08, 95% CI -3.71 to -2.42) with NNT 32. Fourth-degree perineal injuries were reduced from 1.6% to 1.0 % (-0.58%, 95% CI -0.79 to -0.37) with NNT 172.

CONCLUSIONS

Lateral or mediolateral episiotomy reduced the prevalence of OASIS in nulliparous women delivered with vacuum extraction, compared to women with no episiotomy.

TWEETABLE ABSTRACT

To prevent one case of OASIS in first-time mothers delivered with vacuum, 27 episiotomies had to be performed.

FIGO good clinical practice paper: management of the second stage of labor

This good clinical practice paper provides an overview of the current evidence around second stage care, highlighting the challenges and the importance of maintaining high-quality, safe, and respectful care in all settings. It includes a series of recommendations based on best available evidence regarding length of second stage, judicious use of episiotomy, and the importance of competent attendants and adequate resource to facilitate all aspects of second stage management, from physiological birth to assisted vaginal delivery and cesarean at full dilatation. The second stage of labor is potentially the most dangerous time for the baby and can have significant consequences for the mother, including death or severe perineal trauma or fistula, especially where there are failures to recognize and repair. This paper sets out principles of care, including the vital role of skilled birth attendants and birth companions, and the importance of obstetricians and midwives working together effectively and speaking with one voice, whether to women or to policy makers. The optimization of high-quality, safe, and personalized care in the second stage of labor for all women globally can only be achieved by appropriate attention to the training of birth attendants, midwives, and obstetricians. FIGO is committed to this aim alongside the WHO, ICM, and all FIGO's 132 member societies.

Severe Perineal Trauma in a Brazilian Southeastern Tertiary Hospital: A Retrospective Cohort Study

OBJECTIVE

This study aimed to investigate the prevalence of severe perineal trauma (obstetric and anal sphincter injury [OASIS]) in a tertiary high-risk pregnancy facility and the associated factors.

METHODS

A retrospective electronic chart review on perineal lacerations was performed from the period of April 2017 to February 2019. Obstetric and anal sphincter injury was diagnosed by a rectal examination. Primary outcome was the prevalence of OASIS (third- and fourth-degree perineal tear). Independent variables were maternal, intrapartum, and neonatal characteristics. Univariate and multivariate analyses with logistic regression models were performed. A P value lower than 0.05 was considered significant.

RESULTS

The prevalence of OASIS (third/fourth-degree laceration) was 1.51% (43/2846) in our population. Our population was mostly white (66.3%) and mostly primiparous (52.1%). By comparison, the prevalence of first/second-degree laceration was 43% (1223/2846). Selective episiotomy occurred in 18.73% (517/2761) of patients, and it was not associated with OASIS (P = 0.211). Advanced maternal age (P = 0.196), higher number of vaginal examinations (P = 0.169), fetal presentation (P = 0.533), and duration of second stage (P = 0.757) were not associated with OASIS. Univariate analysis has found that forceps delivery (odds ratio [OR], 3.68 [1.74-7.79]; P = 0.001), neonatal macrossomy (OR, 3.42 [1.02-11.43]; P = 0.045), and larger head circumference (OR, 1.15 [1.02-1.32]; P = 0.026) were risk factors for OASIS, whereas higher gravidity reduced the risk (OR, 0.61 [0.42-0.91] for OASIS. However, after multivariate analysis, only head circumference (OR, 1.86 [1.10-3.14]; P = 0.020) remained as a risk factor.

CONCLUSIONS

Larger neonatal head circumference increased in 86% the risk for severe perineal trauma in this cohort of women.

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.

A one-stop perineal clinic: our eleven-year experience

Introduction and hypothesis

The perineal clinic is a dedicated setting offering assessment for various childbirth-related presentations including obstetric anal sphincter injuries (OASIs), perineal wound complications, pelvic floor dysfunction and other conditions such as female genital mutilation(FGM). We describe the clinical presentation and outcomes of women from a tertiary perineal clinic based on data collected over an 11-year period.

Methods

This is a retrospective observational study. A one-stop outpatient service was offered to all women who sustained OASIs (postnatally and antenatally in a subsequent pregnancy), perineal complications (within 16 weeks postpartum), FGM and/or peripartum symptoms of urinary/anal incontinence or prolapse. Assessment included history with validated questionnaires, examination and anal manometry and endoanal ultrasound when appropriate. Outcomes were compared among different grades of OASIs. Management of each type of presentation was reported with outcomes.

Results

There were 3254 first attendance episodes between 2006 and 2016. The majority (58.1%) were for OASIs, followed by perineal wound complications. Compared to the lower grades, the higher grades of OASI were associated with poorer outcomes in terms of symptoms, investigations and complications. Women with OASIs had unrelated symptoms such as urinary incontinence, perineal pain and wound infections that needed further intervention. A high proportion(42%) of wound complications required further specialist management.

Conclusion

We describe a dedicated, one-stop perineal clinic model for antenatal and postnatal women for management of perineal and pelvic floor disorders. This comprehensive and novel data will enable clinicians to better counsel women regarding of outcomes after OASI and focus training to minimize risks of morbidities.

'Please Squeeze': A novel approach to perineal guarding at the time of delivery reduced rates of obstetric anal sphincter injury in an Australian tertiary hospital

BACKGROUND

Over the last decade the incidence of obstetric anal sphincter injuries (OASIS) has been steadily increasing locally and internationally. Investigations into reducing rates, and the long-term complications, of OASIS are required.

AIMS

To determine if applying a new method of perineal guarding at the time of delivery reduces the incidence of OASIS at an Australian tertiary hospital.

MATERIALS AND METHODS

A retrospective audit was performed for the three  years prior to and following mandatory introduction of a new method of perineal guarding. The novel 'Please Squeeze' technique involved placement of the accoucheur's thumb and index finger just above the line of the posterior fourchette at crowning and bringing them firmly one centimetre postero-medially to reduce tension. Demographic data were extracted from the unit's obstetric database (ObstetriX).

RESULTS

There were 9453 deliveries prior to, and 9805 deliveries following commencement of 'Please Squeeze', with no difference in the incidence of caesarean (30.4% vs 30.3% P = 0.87) or forceps (6.3% vs 5.8% P = 0.14) between groups. The incidence of primiparas (P = 0.005), ventouse (P < 0.001) and spontaneous vaginal deliveries (SVD) (P = 0.005) between groups. There was a clinically important 20% reduction in the incidence of OASIS across all vaginal deliveries from 3.5% to 2.8% (P = 0.006). In SVD, there was a 20% decrease in OASIS from 2.4% to 2.2% (P = 0.02), and a 14% decrease in OASIS with assisted vaginal delivery from 8% to 7.3% (P = 0.002). The incidence of episiotomy increased 16% (P < 0.001).

CONCLUSIONS

The novel 'Please Squeeze' perineal guarding method contributed to a reduced incidence of OASIS in an Australian tertiary hospital.

Episiotomy: a medicolegal vicious cycle

The present study aimed to analyze the litigation trends and ensuing compensatory damages brought about by the use of episiotomy, in order to outline a set of cautionary rules meant to limit the scope of legreal aftermath for both doctors and health care facilities. The authors have set out to gain an insight into the controversial practice of episiotomy, in light of available research data and official positions of various scientific and medical associations, with a close focus on the legal and medical viability of the procedure itself. Court data and trial records have been taken into account as well, via searches into legal databases and search engines (Justia, Lexis, Jurist.org, Venice Courthouse, etc.). This review showed that most episiotomy-related lawsuits stemmed from a routine use of that procedure, which is almost universally advised against, and without valid informed consent having been gained. Ultimately, authors have seen fit to underscore the need for patients potentially eligible for an episiotomy (selective episiotomy) to receive thorough and understandable information in a timely fashion including the necessity and the effectiveness of the procedure as well as the risks involved, so that a well-informed decision can be made based on factual data.

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.

Risk factors for obstetric anal sphincter injuries at vaginal birth after caesarean: a retrospective cohort study

INTRODUCTION AND HYPOTHESIS

Vaginal birth after caesarean (VBAC) is associated with an increased risk of obstetric anal sphincter injuries (OASIS). However, specific factors that influence the risk of OASIS at VBAC have not been studied, particularly whether there are specific baseline characteristics of the first delivery which affect the subsequent perineal outcomes.

METHODS

Retrospective analysis of prospectively collected data from University of Southampton NHS Foundation Trusts' maternity database. This included secundiparous women with a previous caesarean delivery (CS) who achieved a singleton, term, cephalic vaginal delivery from 2004 to 2014. Univariate analysis compared maternal, intrapartum and neonatal factors of those who suffered OASIS at VBAC with those who did not. A binary logistic regression model calculated the adjusted, independent odds ratio (OR) of OASIS.

RESULTS

A total of 1375 women met the inclusion criteria. The OASIS rate was 8.1%, a 1.4-fold increase compared with primiparous women [difference 2.4% (95% CI 1.1, 3.6)]. Those sustaining OASIS at VBAC were older (p = 0.011) and had infants of greater birth weight at initial caesarean (p < 0.001) and VBAC (p = 0.04). Analysis of odds ratios revealed that mediolateral episiotomy (MLE) at VBAC halved the risk of OASIS [37.5% VBAC with OASIS vs. 52.2% VBAC without OASIS (OR 0.51, 95% CI 0.32-0.81)], whereas an urgent CS at initial delivery doubled the risk [52.3% VBAC with OASIS vs. 34.9% VBAC without OASIS (OR 2.05, 95% CI 1.31-3.21)].

CONCLUSIONS

Advanced maternal age, increased infant birth weight and an urgent category of initial CS increase the risk of OASIS at VBAC, whereas MLE is protective.

The consequences of undiagnosed obstetric anal sphincter injuries (OASIS) following vaginal delivery

INTRODUCTION AND HYPOTHESIS

We aimed to compare anal and urinary incontinence symptoms and anal manometry between women with undiagnosed obstetric anal sphincter injuries (OASIS) and women who had OASIS diagnosed and repaired.

METHODS

This was a matched retrospective cohort study. Each missed OASI was matched with a diagnosed OASI for severity [minor (3a/b) or major (3c)], parity and length of follow-up. Women completed the modified St Mark's Incontinence Score and International Consultation on Incontinence Questionnaire. Women with OASIS or those without OASIS but with anal incontinence symptoms were seen in perineal clinic for perineal examinations, anorectal manometry and three-dimensional endoanal ultrasound 8-12 weeks postnatally or in a subsequent pregnancy.

RESULTS

Forty missed OASIS were matched with 40 recognised OASIS (16 3a/b; 24 3c). The median modified St Mark's scores were higher for missed tears [11 (4, 15) vs. 1 (0, 4), p < 0.001] as well as the urinary incontinence scores [4 (0, 6) vs. 0 (0, 2), p = 0.01] than for the control group. Missed OASIS patients had a shorter perineal body [1.6 ± 1.3 vs. 2.4 ± 0.8, p = 0.009]. All missed OASIS had larger defects on endoanal ultrasound. One in four missed OASIS required further surgery [aOR 4.1 (95% CI 1.0-16.3), p = 0.04] and almost all needed colorectal input [aOR 24.1 (95% CI 7.3-80.0), p < 0.0001]. There were no differences in anal manometry.

CONCLUSIONS

Women with symptomatic missed OASIS are compromised in terms of anal and urinary incontinence symptoms, sphincter defect size and perineal body size requiring additional colorectal input. This highlights the importance of preventing OASIS and perseverance with training to diagnose OASIS.

FIGO Statement: Restrictive use rather than routine use of episiotomy

International standards for clinical staffing of delivery care in maternity units are currently lacking, with resulting gaps in provision leading to adverse outcomes and very poor experiences of care for women and families. While evidence‐informed modelling approaches have been proposed based on population characteristics and estimated rates of complications, their application and outcomes in low‐resource settings have not been reported. Here, FIGO's Safe Motherhood and Newborn Health Committee proposes indicative standards for labor wards as a starting point for policy and program development. These standards consider the volume of deliveries, the case mix, and the need to match clinical care requirements with an appropriate mix of professional skills among midwifery and obstetric staff. The role of Shift Leader in busy labor wards is emphasized. Application of the standards can help to assure women and their families of a safe but also positive birthing experience. FIGO calls for investment by partners to test these clinically‐informed recommendations for delivery unit staffing at hospital and district level in low‐ and middle‐income country settings.

Which characteristics of the episiotomy and perineum are associated with a lower risk of obstetric anal sphincter injury in instrumental deliveries

OBJETIVE

Operative vaginal delivery (OVD) is the most important risk fact for obstetric anal sphincter injury (OASI). Knowledge of possible risk factors for their occurrence may therefore reduce the likelihood of faecal incontinence. The aim is to analyse the effect of mediolateral episitomy and perineum characteristics on the occurrence of OASI in OVD.

STUDY DESIGN

Case-control study, which included 958 OVD that were reviewed in Pelvic Floor and Puerperium Clinic. The episiotomy and perineum characteristics of those women who experienced OASIs (n = 150) were compared with those who had no evidence of anal sphincter injury (n = 788).

RESULTS

In multivariate logistic regression analysis the factors which were independently associated were nulliparity, persistent occipitoposterior position, birthweight >3500 g, an angle of episiotomy <30°, a distance episiotomy-fourchette <5 mm and a distance of perineal body <30 mm. The analysis of subgroups show that only the multiparous women does not benefit from any feature of the episiotomy, and an angle greater than 30° and a distance episiotomy-fourchette >5 mm are associated with a risk reduction of OASI in nulliparous, perineal bodies ≤30 mm and occipitoanterior position.

CONCLUSIONS

Two modifiable risk factors at the time of performing the episiotomy, the angle and distance episiotomy-fourchette, have been identified as the risk modification of OASI. It is necessary to achieve an adequate angle to reduce the probability of OASIs in OVD, and in nulliparous women with an anterior position and a distance of perineal body ≤30 mm could benefit from increasing the episiotomy-fourchette distance.

[Fetal expulsion: Which interventions for perineal prevention? CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVE

The objective for all obstetricians and midwifes who intervene during the release of the fetal presentation is to prevent at best the perineal lesions. This work consisted in analyzing the literature, researching and evaluating interventions that reduce this perineal risk during the release.

METHODS

A keyword search for each medical intervention during the expulsion phase was conducted by selecting studies assessing perineal risk. Interventions during pregnancy and during delivery before the expulsion phase were specifically addressed in other sections of the recommendations.

RESULTS

Firstly, the degree of perineal stretching during the second stage of labour does not appear to be a risk factor for OASIS, postpartum incontinence, or sexual disorders (LE3) and that a substantial stretching of the perineum is not an indication of episiotomy (Professional consensus). Then, manual control of the expulsion of the fetus at the end of the second stage of labour and support of the posterior perineum during this time appear to reduce the rate of OASIS (LE3). The crowning of the baby's head should be manually controlled and the posterior perineum manually supported manually to reduce the risk of OASIS (GradeC). There is no recognised benefit to episiotomy in normal deliveries (LE1); the liberal practice of episiotomy results in fewer intact perineums than its restrictive practice, and the latter does not result in increasing the number of cases of OASIS. No evidence indicates that an episiotomy for women with a breech presentation, twin pregnancy, or posterior position prevents OASIS (LE3). Indication for episiotomy during delivery depends on individual risk factors and obstetric conditions (Professional consensus). It is recommended that the indication for episiotomy be explained and the woman's consent received before its performance. The performance of an episiotomy during normal deliveries is not recommended to reduce the risk of OASIS (Grade A). The liberal practice of episiotomy to prevent OASIS is not recommended for women with a breech presentation, twin pregnancy, or posterior position (GradeC). Episiotomy during an instrumental delivery appears to be associated with a reduction of the risk of OASIS (LE3). The vacuum extractor appears to induce fewer cases of OASIS than other instruments (LE3). Episiotomy may be indicated in instrumental deliveries to avoid OASIS (GradeC). Training in perineal protection in obstetrics is recommended (Grade B). In operative vaginal deliveries when several instruments can be used, a vacuum extractor is preferentially recommended to reduce the risk of OASIS (GradeC). When forceps or spatulas are used, it is preferable that they be withdrawn just before cephalic deflexion so that the fetal head is not "capped" with these instruments at birth (Professional consensus). Couder's maneuver, which consists of lowering the forearm during the release of the fetal shoulders, appears to decrease the rate of second-degree perineal tears and increase the rate of intact perineum (LE3).

CONCLUSION

Manual control of the expulsion and perineal support reduce the risk of perineal injury. There is no benefit to episiotomy in normal delivery, nor in special cases such the breech presentation for example. On the other hand, in case of instrumental delivery, an episiotomy may be indicated to avoid OASIS (GradeC), and it is recommended if it is possible to use the ventouse preferentially. The Couder's maneuver seems to reduce the rate of 2^nd degree perineal lesions (LE3). Finally, training in perineal obstetric protection is recommended (Grade B).

Applying a Midwifery-Specific Decision-Making Tool to Midwives’ Clinical Reasoning and Midwifery Practice When Managing a Woman’s Perineum in Labor: An Exploratory Study

Introduction: Many of the risk factors for perineal trauma are modifiable, and midwives are in an ideal position to mitigate such risks. To date, no investigation using a midwifery-specific decision-making tool has sought to determine how midwives make decisions within a midwifery philosophy/context or identify the factors that may contribute to that decision making about perineal management. We sought to apply such a tool to midwives’ narratives and explore their clinical reasoning and midwifery practice when managing a woman’s perineum in labor.

Methods: A qualitative interview-based study with practicing midwives in one regional Australian maternity unit was conducted. The decision-making matrix specified by a psychometrically robust and validated measure of clinical decision making and midwifery practice-guided analysis.

Results: Effective clinical decision making in response to perineal trauma is contingent on a heuristic and individualized “working hypothesis” that combines distinct elements of an optimal clinical decision-making process. Midwives’ narratives highlighted their ability to engage in some form of clinical reasoning. Some elements of midwifery practice was lacking within several midwives’ narratives, thus resulting in them abdicating their professional role.

Conclusion: The manner and processes by which midwives engage effectively with perineal management are complex. However, a significant influence on this process appears to be recollections from original training in perineal management, which appears to be largely rote and taught by example. We recommend balance between practical experience and synthesis with current evidence within a midwifery philosophy to optimize perineal care and risk modification.

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.

Prospective comparison of obstetric anal sphincter injury incidence between an Asian and Western hospital

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injury (OASIS) rates are reported to be higher in Asian women living in Western countries than in those living in Asia, but the reasons for the differences remain unclear. The objectives of this study were for a single examiner to prospectively compare OASIS rates in primiparous Asian women in an Asian and Western birth unit and determine potential birth factors that may influence the possible difference in OASIS incidence.

METHODS

This was a prospective observational study based in Hong Kong, China, and Sydney, Australia, involving primiparous women > 36 weeks gestation of Asian descent undergoing vaginal delivery. A single examiner recorded basic patient demographics, observed all the deliveries at both sites, noting birthing techniques, and then examined the women, including a rectal examination, to determine OASIS incidence.

RESULTS

Seventy births in Hong Kong and 66 in Sydney were studied. The incidence of OASIS was 34% in Sydney and 10% in Hong Kong (p = 0.001). Birthweight, epidural rate, body mass index, and instrumental delivery were higher in Sydney. Episiotomy rates were higher in Hong Kong (59.2% vs. 82.9%; p = 0.007). When comparing OASIS with no-OASIS, perineal length (OR = 0.36, 95% CI 0.17 to 0.76, p = 0.004) and birthweight (OR = 1.14, 95% CI 1.00 to 1.30, p = 0.039) were independent risk factors for OASIS.

CONCLUSIONS

The incidence of OASIS in Asian women is significantly higher in a Western than in an Asian setting. In Asian women, perineal length and birthweight can affect the risk of OASIS at the time of vaginal delivery.

Can We Deliver Better?

Human childbirth has been described as an "obstetrical dilemma". Evolution favours enlargement of the foetal brain, whilst bipedal locomotion demands a reduction in pelvic breadth for improvements in biomechanical efficiency. The result of this conflict is a human pelvis incongruous with the dynamics of childbirth. Acute genital distortion at delivery can inflict lasting damage to female pelvic function. Pelvic organ prolapse, urinary, faecal incontinence and sexual dysfunction are long-term sequelae rarely discussed at antenatal care, impacting upon the expectant mother's ability to make an informed decision. The alternative option is the elective caesarean section, an abdominal incision bypassing the maladies of a vaginal delivery, although not without complications of its own. Childbirth remains an emotive event where evidence-based medicine can be disempowered, and the rising trend to "normalise" birth can disrupt care of the woman. This needs to be maintained in a healthy balance to best provide competent and safe care for women.

Exercise and pregnancy in recreational and elite athletes: 2016 evidence summary from the IOC expert group meeting, Lausanne. Part 2-the effect of exercise on the fetus, labour and birth

This is Part 2 of 5 in the series of evidence statements from the IOC expert committee on exercise and pregnancy in recreational and elite athletes. Part 1 focused on the effects of training during pregnancy and on the management of common pregnancy-related symptoms experienced by athletes. In Part 2, we focus on maternal and fetal perinatal outcomes.