Obstetric anal sphincter injuries during instrumental vaginal delivery: An observational study based on 18-years of real-world data

OBJECTIVE

To determine the prevalence and secular trends of obstetric anal sphincter injuries (OASIS) in vacuum and forceps deliveries in Norway, both with and without episiotomy.

DESIGN

Population-based real-world data collected during 2001-2018.

SETTING

Medical Birth Registry Norway.

POPULATION OR SAMPLE

Nulliparous women with singleton foetuses in a cephalic presentation delivered by either vacuum or forceps (n = 70 783).

METHODS

Logistic regression analyses were applied to the OASIS prevalence in six 3-year time periods. Both crude odds ratios and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were determined.

MAIN OUTCOME MEASURES

OASIS prevalence.

RESULTS

The OASIS prevalence in vacuum and forceps deliveries decreased from 14.8% during 2001-2003 to 5.2% during 2016-2018. The overall reduction between the first and last 3-year time period was 61% (aOR = 0.39, 95% CIs = 0.35-0.43). The only exception to this decreasing trend in OASIS was found in forceps deliveries performed without an episiotomy. The OASIS prevalence was approximately twofold higher in forceps compared to vacuum deliveries (aOR = 1.92, 95% CIs = 1.79-2.05). Performing either a mediolateral or lateral episiotomy was associated with a 45% decrease in the prevalence of OASIS relative to no episiotomy (aOR = 0.55, 95% CIs = 0.52-0.58).

CONCLUSIONS

Opting for vacuum rather than forceps delivery in conjunction with a mediolateral or lateral episiotomy could significantly lower the OASIS prevalence in nulliparous women.

The association between waterbirth and perineal injury or other adverse outcomes among low-risk women with physiological birth: Results from the Nordic Home Birth Cohort Study

PROBLEM/BACKGROUND

Immersion in water has known benefits, such as reducing pain and shortening the duration of labour. The relationship between waterbirth and perineal injury remains unclear.

AIM

To compare the incidence of perineal injury in waterbirth and birth on land among low-risk women. Secondary outcomes were postpartum haemorrhage and 5-minute Apgar scores <7.

METHODS

Prospective cohort study of 2875 low-risk women who planned a home birth in Denmark, Iceland, Norway, and Sweden in 2008-2013 and had a spontaneous vaginal birth without intervention. Descriptive statistics and logistic regression were performed.

FINDINGS

A total of 942 women had a waterbirth, and 1933 gave birth on land. The groups differed in their various background variables. Multiparous women had moderately lower rates of intact perineum (59.3% vs. 63.9%) and primiparous women had lower rates of episiotomies (1.1% vs. 4.8%) in waterbirth than in birth on land. No statistically significant differences were detected in adjusted regression analysis on intact perineum in waterbirth (primiparous women's aOR = 1.03, CI 0.68-1.58; multiparous women's aOR = 0.84, CI 0.67-1.05). The rates of sphincter injuries (0.9% vs. 0.6%) were low in both groups. No significant differences were detected in secondary outcomes.

DISCUSSION

The decreased incidence of intact perineum among multiparous women was modest and inconclusive, and the prevalence of sphincter injury was low.

CONCLUSION

Low-risk women contemplating waterbirth should be advised to weigh the risks and benefits detected in this study against previously established benefits of waterbirth and should make an informed choice based on their values.

Prevention of obstetric anal sphincter injuries with perineal support and lateral episiotomy: A historical cohort study

INTRODUCTION

There are many risk factors for obstetric anal sphincter injury (OASIS) and the interaction between these risk factors is complex and understudied. The many observational studies that have shown a reduction of OASIS rates after implementation of perineal support have short follow-up time. We aimed to study the effect of integration of active perineal support and lateral episiotomy on OASIS rates over a 15-year period and to study interactions between risk factors known before delivery.

MATERIAL AND METHODS

We performed a historical cohort study over the periods 1999-2006 and 2007-2021 at Stavanger University Hospital, Norway. The main outcome was OASIS rates. Women without a previous cesarean section and a live singleton fetus in cephalic presentation at term were eligible. The department implemented in 2007 the Finnish concept of active perineal protection, which includes support of perineum, control of fetal expulsion, good communication with the mother and observation of perineal stretching. The practice of mediolateral episiotomy was replaced with lateral episiotomy when indicated. We analyzed the OASIS rates in groups with and without episiotomy stratified for delivery mode, fetal position at delivery and for parity, and adjusted for possible confounders (maternal age, gestational age, oxytocin augmentation and epidural analgesia).

RESULTS

We observed a long-lasting reduction in OASIS rates from 4.9% to 1.9% and an increase in episiotomy rates from 14.4% to 21.8%. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with instrumental vaginal deliveries and occiput anterior (OA) position; 3.4% vs 10.1% (OR 0.31; 95% CI: 0.24-0.40) and 6.1 vs 13.9% (OR 0.40; 95% CI: 0.19-0.82) in women with occiput posterior (OP) position. Lateral episiotomy was also associated with lower OASIS rates in nulliparous women with spontaneous deliveries and OA position; 2.1% vs 3.2% (OR 0.62; 95% CI: 0.49-0.80). The possible confounders had little confounding effects on the risk of OASIS in groups with and without episiotomy.

CONCLUSIONS

We observed a long-lasting reduction in OASIS rates after implementation of preventive procedures. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with an instrumental delivery. Special attention should be paid to deliveries with persistent OP position.

Risk of obstetric anal sphincter injury associated with female genital mutilation/cutting and timing of deinfibulation

INTRODUCTION

A greater risk of obstetric anal sphincter injury has been reported among African migrants in several host countries compared with the general population. To what degree female genital mutilation/cutting affects this risk is not clear. In infibulated women, deinfibulation prevents anal sphincter injury. Whether the timing of deinfibulation affects the risk, is unknown. This study aimed to investigate the risks of anal sphincter injury associated with female genital mutilation/cutting and timing of deinfibulation in Norway, and to compare the rates of anal sphincter injury in Somali-born women and the general population.

MATERIAL AND METHODS

In a historical cohort study, nulliparous Somali-born women who had a vaginal birth in the period 1990-2014 were identified by the Medical Birth Registry of Norway and data collected from medical records. Exposures were female genital mutilation/cutting status and deinfibulation before labor, during labor or no deinfibulation. The main outcome was obstetric anal sphincter injuries.

RESULTS

Rates of obstetric anal sphincter injury did not differ significantly by female genital mutilation/cutting status (type 1-2: 10.2%, type 3: 11.3%, none: 15.2% P = 0.17). The total rate of anal sphincter injury was 10.3% compared to 5.0% among nulliparous women in the general Norwegian population. Women who underwent deinfibulation during labor had a lower risk than women who underwent deinfibulation before labor (odds ratio 0.48, 95% confidence interval 0.27-0.86, P = 0.01).

CONCLUSIONS

The high rate of anal sphincter injury in Somali nulliparous women was not related to type of female genital mutilation/cutting. Deinfibulation during labor protected against anal sphincter injury, whereas deinfibulation before labor was associated with a doubled risk. Deinfibulation before labor should not be routinely recommended during pregnancy.

Which elements were significant in reducing obstetric anal sphincter injury? A prospective follow-up study

Background

To examine which elements of an obstetric anal sphincter injury (OASI) care bundle were protective for OASI. Several interventional trials showed that application of a care bundle involving a hands-on approach to perineal protection may reduce the risk of OASI. Previously, we found that only the element “hand on the fetal head” in itself was protective, although the risk of a type 2 error was calculated to be 50%.

Methods

A prospective follow-up study in an obstetric department in Denmark with 3200 deliveries per year. We included a cohort of 10,383 women giving birth vaginally from gestational week 22 + 0 from 2016 through 2019. We documented on a person-level the five elements of the care bundle together with maternal and obstetrical characteristics. The elements were 1) communication, 2) visible perineum, 3) hand on fetal head, 4) perineal support and 5) certification. Regression analysis was used for analysis of associations. The primary outcome measure was OASI.

Results

The total rate of OASI in vaginally delivering women was 1.9%. The incidence was 3.2% in nulliparous women giving birth vaginally. The rate of cesarean section was 16.5% and for episiotomy 2.4%. The reduction in the incidence of OASI was sustained since 2013. Hand on the fetal head and perineal support both were protective factors for OASI. In case of a nulliparous woman with a neonate weighing 3500 g giving birth spontaneously, the relative risk (RR) for OASI was 0.50 (95% CI 0.49- 0.51) with use of hand on the fetal head together with perineal support against no use. Similarly, with a nulliparous woman giving birth to a neonate of 3500 g by vacuum extraction, the RR for OASI was 0.65 (95% CI 0.62-0.68) against no use.

Conclusions

Both hand on the fetal head and perineal support were associated with a reduced risk of OASI.

How a perineal care bundle impacts midwifery practice in Australian maternity hospitals: A critical, reflexive thematic analysis

BACKGROUND

A care bundle to reduce severe perineal trauma (the bundle) was introduced in 28 Australian maternity hospitals in 2018. The bundle includes five components of which only one - warm perineal compresses - has highest level evidence. There is scant published research about the impact of implementation of perineal bundles.

QUESTION

How does a perineal care bundle impact midwifery practice in Australian maternity hospitals?

METHODS

Purposively sampled midwives who worked in hospitals where the bundle had been implemented. Interested midwives were recruited to participate in one-to-one, semi-structured interviews. The researchers conducted critical, reflexive thematic analysis informed by Foucauldian concepts of power.

FINDINGS

We interviewed 12 midwives from five hospitals in one state of Australia. Participants varied by age, clinical role, experience, and education. Three themes were generated: 1) bundle design and implementation 2) changing midwifery practice: obedience, subversion, and compliance; and 3) obstetric dominance and midwifery submission.

DISCUSSION

The bundle exemplifies tensions between obstetric and midwifery constructs of safety in normal birth. Participants' responses appear consistent with oppressed group behaviour previously reported in nurses and midwives. Women expect midwives to facilitate maternal autonomy yet decision-making in maternity care is commonly geared towards obtaining consent. In our study midwives encouraged women to consent or decline depending on their personal preferences.

CONCLUSION

The introduction of the perineal bundle acts as an exemplar of obstetric dominance in Australian maternity care. We recommend midwives advocate autonomy - women's and their own - by using clinical judgement, evidence, and woman-centred care.

Effects of Fourth-Degree Perineal Lacerations on Women's Physical and Mental Health

OBJECTIVE

To describe the physical and emotional effects of fourth-degree perineal lacerations that occur during childbirth.

DESIGN

Descriptive phenomenology.

SETTING

Internet survey.

PARTICIPANTS

Eighteen women from the United States, the United Kingdom, Australia, and Canada who sustained fourth-degree perineal lacerations during childbirth.

METHODS

Women were recruited from the Facebook support group Mothers With 4th Degree Tears. Participants were asked to describe the physical and emotional effects of these severe birth injuries on their daily lives. I analyzed these data using Colaizzi's method for phenomenological analysis.

RESULTS

The devastating effects of these birth-related injuries permeated all aspects of the lives of participants. Participants did not receive adequate information about their perineal lacerations, and clinicians often dismissed their concerns. Some participants struggled with postpartum depression and posttraumatic stress disorder. I identified seven themes that described the effects of fourth-degree perineal lacerations: Why Wasn't I Informed I Had This Injury?; The Unthinkable: Fecal Incontinence and So Much More; It Has Cost Me So Much; Seeking Relief: Enduring Surgery After Surgery; Why Didn't Anyone Ask Me About My Mental Health?; To Have More Children, That Is The Question; And Are there Any Positives In All Of This?

CONCLUSION

Women need information to prepare for recovery from their severe perineal injuries related to what to expect, how to care for themselves, and what resources are available. Clinicians have a responsibility to provide a caring environment in which women feel safe to disclose any problems they are experiencing as a result of their perineal injuries. Little, if any, attention is focused on women's mental health by clinicians or researchers as women struggle with the aftermath of fourth-degree perineal lacerations.

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.

Birth tears after spontaneous and vacuum-assisted births with different vacuum cup systems - a retrospective cohort study

Objectives Birth tears are a common complication of vaginal childbirth. We aimed to evaluate the outcomes of birth tears first by comparing the mode of vaginal birth (VB) and then comparing different vacuum cups in instrumental VBs in order to better advise childbearing women and obstetrical professionals. Methods In a retrospective cohort study, we analyzed nulliparous and multiparous women with a singleton pregnancy in vertex presentation at ≥37 + 0 gestational weeks who gave birth vaginally at our tertiary care center between 06/2012 and 12/2016. We compared the distribution of tear types in spontaneous births (SBs) vs. vacuum-assisted VBs. We then compared the tear distribution in the vacuum group when using the Kiwi Omnicup or Bird's anterior metal cup. Outcome parameters were the incidence and distribution of the different tear types dependent on the mode of delivery and type of vacuum cup. Results A total of 4549 SBs and 907 VBs were analyzed. Birth tear distribution differed significantly between the birth modes. In 15.2% of women with an SB an episiotomy was performed vs. 58.5% in women with a VB. Any kind of perineal tear was seen in 45.7% after SB and in 32.7% after VB. High-grade obstetric anal sphincter injuries (OASIS) appeared in 1.1% after SB and in 3.1% after VB. No significant changes in tear distribution were found between the two different VB modes. Conclusions There were more episiotomies, vaginal tears and OASIS after VB than after SB. In contrast, there were more low-grade perineal and labial tears after SB. No significant differences were found between different vacuum cup systems, just a slight trend toward different tear patterns.

Metrics of perineal support (MOPS) study

BACKGROUND

Manual perineal protection (MPP) is an intrapartum intervention suggested to protect perineal integrity during childbirth. Proper execution of MPP is complex and evaluation of its true contribution is difficult in the clinical setting because of the large number of obstetric variables, some of which are hardly quantifiable. In this study we aimed to gather initial data on the forces executed by the accoucheur's thumb, index and middle fingers during MPP at the time of fetal head expulsion, quantify the duration of the intervention and investigate the timely interaction of the different components of MPP.

METHODS

Two bespoke right-handed measurement gloves (MG), with built in sensors, were designed and produced. The MG allowed the electronic real-time measurement of applied forces during MPP and transferred this data wirelessly to an integrated computer system. Sterile gloves were worn over the MG when used at the time of birth. The study was undertaken between January and December 2019. Singleton, term pregnant women having their first vaginal birth who provided a valid written consent were enrolled into this prospective pilot study. All deliveries were undertaken by one of two obstetricians experienced in MPP.

RESULTS

Twenty women were enrolled. The mean duration of execution of MPP during the last contraction was 13.6 s. In 20% it lasted < 5 s. The overall mean values of the average and maximum forces of the thumb, index and middle fingers were 26.7 N; 25.5 N; 20.2 N and 34.3 N; 32.6 N; and 27.6 N respectively. The onset of fingers and thumb activity was simultaneous in 13 cases (65%), while in seven (35%) deliveries the middle finger's force activity was initiated later.

CONCLUSIONS

MPP during fetal head expulsion happens over a short period of time. In the majority of cases the thumb and fingers actions started simultaneously. There were differences in the duration of application and the forces executed by the fingers and thumb between the two practitioners, however this was only significant for thumb measurements. The results obtained will aid in improving further MPP modeling studies to optimize the technique.

Risk Factors for Obstetric Anal Sphincter Injuries among Women Delivering at a Tertiary Hospital in Southwestern Uganda

Background

Obstetric anal sphincter injuries (OASIS) arise from perineal trauma during vaginal delivery and are associated with poor maternal health outcomes. Most OASIS occur in unattended deliveries in resource-limited settings. However, even in facilities where deliveries are attended by skilled personnel, a number of women still get OASIS.

Objectives

To determine the incidence and risk factors for obstetric anal sphincter injuries among women delivering at Mbarara Regional Referral Hospital (MRRH).

Methods

We conducted an unmatched hospital-based case control study, with the ratio of cases to controls of 1 : 2 (80 cases and 160 controls). We defined a case as a mother who got a third- or fourth-degree perineal tear after vaginal delivery while the controls recruited were the next two mothers who delivered vaginally without a third- or fourth-degree perineal tear. A questionnaire and participants' medical records review were used to obtain sociodemographic and clinical data. We estimated the incidence of OASIS and performed univariable and multivariable logistic regression to identify the associated risk factors.

Results

The cumulative incidence for OASIS during the study period was 6.6%. The risk factors for OASIS were 2^nd stage of labour ≥1 hour (aOR 6.07, 95%CI 1.86–19.82, p=0.003), having episiotomy performed during labour (aOR 2.57, 95%CI 1.07–6.17, p=0.035), perineum support during delivery (aOR 0.03, 95%CI 0.01–0.12, p < 0.001), and monthly income of >50,000 shillings (aOR 0.09, 95%CI 0.03–0.28, p < 0.001). Conclusions and Recommendations. The risk factors for obstetric anal sphincter injury were prolonged second stage of labour and performing episiotomies during deliveries while higher monthly income and perineum support during delivery were protective. We recommend routine support to the perineum during delivery. Care should be taken in mothers with episiotomies, as they can extend and cause OASIS.

How do sustained birth tears after vaginal birth affect birth tear patterns in a subsequent birth?

Background Tears are common after vaginal birth, and different impact factors are known. However, the impact of tears from a previous birth to the tears of a subsequent birth is unknown. Therefore, we aimed to evaluate the distribution of birth tear patterns according to the sustained tears in a previous birth, in addition to other impact factors. Methods In a retrospective cohort study, we evaluated all women up to parity 4 with subsequent vaginal, singleton births of vertex presentation at ≥37 + 0 gestational weeks between 1/2005 and 12/2016. Their tears were grouped into tear patterns and were analyzed by parity. Tear patterns in the subsequent births were analyzed in association to the patterns of the previous births and impact factors were evaluated. Results We counted 4017 births in 1855 women [P1: 1368 (34.1%), P2: 1730 (43.1%), P3: 741 (18.4%), P4: 178 (4.4%)]. The frequency of tears and episiotomies decreased with higher parity, whereas the frequency of intact perineum increased. Twenty-eight different unique tear patterns were found. We could show that birth tear patterns changed with increasing parity and were associated with sustained tears in a previous birth. In addition, some impact factors on tear patterns could be identified. Conclusion The distribution of the single tear types is in accordance with the current literature. However, it is new that distinct tear patterns are associated to sustained tear patterns of previous births. Furthermore, we demonstrated some weak associations of tear patterns to certain impact factors, such as more episiotomies, low-grade perineal or vaginal tears isolated or in combination with other tears with increasing fetal weight and head circumference in the higher parities, and with a longer duration of the second stage and the pushing phase in lower parities.

Are women attending a midwifery-led birthing center at increased risk of anal sphincter injury?

INTRODUCTION AND HYPOTHESIS

In recent years there has been renewed interest in midwifery-led care for women, with studies reporting similar neonatal outcomes despite lower rates of intervention in midwifery-led birthing centers. Research into obstetric anal sphincter injuries (OASI) in these birthing centers is scarce. The objective of this study was to compare the rate of OASI after spontaneous vaginal delivery in nulliparous women in consultant or midwifery-led units over a ten-year period.

METHODS

All spontaneous vaginal deliveries in nulliparous women from 2008 to 2017 were analyzed in a single-center retrospective study. Women who had neuraxial analgesia were excluded. The primary endpoint was OASI. Labor characteristics in both groups were compared, and a multiple regression model was created.

RESULTS

During the study period, there were 3260 spontaneous vaginal deliveries in nulliparous women; 75.7% (2467/3260) delivered in the consultant-led unit and 24.3% (793/3260) in the midwifery-led unit (MLU). Women delivering in the MLU had a greater risk of anal sphincter injury than those delivering in the CLU (4.9% [39/793] vs 2.5% [62/2467], OR 2.01, 95% CI 1.32 - 3.01). Significant risk factors that increased the risk of OASI on regression analysis were birthweight and delivery in the midwifery-led unit.

CONCLUSIONS

Women delivering in the midwifery-led unit appear to be at double the risk of OASI when compared to those delivering in the consultant-led unit. These results are in contrast to previous studies in midwifery-led centers. This difference may be site-specific and further research is required before these results form part of patient counseling.

Incidence and risk factors for obstetric anal sphincter ruptures, OASIS, following the introduction of preventive interventions. A retrospective cohort study from a Norwegian hospital 2012-2017

OBJECTIVE

A decrease of obstetric anal sphincter injuries (OASIS) was observed after preventive interventions were implemented at a Norwegian university hospital. The aim was to investigate whether the improvement had sustained over the following years.

MATERIALS AND METHODS

We performed a retrospective cohort study of 18 258 singleton vaginal cephalic births, ≥37 + 0 weeks of gestation during 2012-2017, examining data from the hospital's birth journals and separate registration forms. Interventions to prevent OASIS were implemented in 2011, and training in practical skills was repeated each year.

MAIN OUTCOME MEASURES

The main outcome was OASIS (n = 377).

RESULTS

Frequency of OASIS overall decreased from 3.6% prior to 2011 to 2.1% after the intervention and sustained at that level throughout the study period. A trend of fewer OASIS among spontaneous deliveries, decreasing from 2.1% to 1.2% (p = 0.01) was observed, but no trend was seen for instrumental deliveries (p = 0.37), where the incidence fluctuated between 4.0% and 9.3% with an average of 6.5%. Primiparity, increased maternal age and increased fetal head circumference were associated with more OASIS in spontaneous deliveries. In instrumental deliveries, primiparity, occiput posterior position and increased fetal head circumference were associated with more OASIS, whilst episiotomy was associated with fewer OASIS.

CONCLUSION

The incidence of obstetric anal sphincter injuries maintained at a similar level of around 2.1% during the six following years after introducing preventive interventions. Regularly repetition and practical training seemed to be effective.

Effects of an intervention program for reducing severe perineal trauma during the second stage of labor

BACKGROUND

Obstetric anal sphincter injuries lead frequently to short- and long-term consequences for the mother, including perineal pain, genital prolapse, and sexual problems. The aim of the study was to evaluate whether the implementation of an intervention program in the second stage of labor involving altered perineal support techniques reduced severe perineal trauma.

METHODS

All women reaching the second stage of labor and giving birth vaginally to singleton babies at Landspítali University Hospital (comprising 76% of births in Iceland in 2013) were enrolled in a cohort study. Data were recorded retrospectively for 2008-2010 and prospectively in 2012-2014, for a total of 16 336 births. During 2011, an intervention program was implemented, involving all midwives and obstetricians working in the labor wards. Two professionals assessed and agreed on classification of every perineal tear.

RESULTS

The prevalence of obstetric anal sphincter injuries decreased from 5.9% to 3.7% after the implementation (P < 0.001). Third-degree tears decreased by 40%, and fourth-degree tears decreased by 56% (P < 0.001). The prevalence of first-degree tears increased from 25.8% to 33.1%, whereas second-degree tears decreased from 44.7% to 36.6% between the before and after study periods. Severe perineal trauma was linked to birthweight, and this did not change despite the new intervention.

CONCLUSIONS

Active intervention to reduce perineal trauma was associated with an overall significant decrease in obstetric anal sphincter injuries. Good perineal visualization, manual perineal support, and controlled delivery of the fetal head were essential components for reducing perineal trauma.

Coaching a slow birth with the woman in an empowered position may be less harmful than routine hands-on practice to protect against severe tears in birth - A discussion paper

BACKGROUND

Different hands-on interventions to protect women from severe perineal tears after birth have been widely implemented. Evidence to support the routine use of hands-on interventions to reduce severe tears is mainly based on aggregated data from observational studies.

AIM

To critically discuss the current evidence for the implementation of hands-on intervention as a routine practice to protect women from severe tears after birth.

DISCUSSION

Observational studies have been used to justify the routine use of hands-on intervention to protect women from severe perineal tears despite randomized controlled trials and systematic reviews showing lack of benefit. There is strong evidence supporting the slow speed at the time of birth to prevent severe perineal tears. While hands-on intervention does reduce the speed of birth, it may have a negative effect on the birth process, on neonatal outcomes and women's agency.

CONCLUSION

Evidence-based practice requires sufficient evaluation of interventions before being implemented in clinical practice as well as valuing the level of evidence when making clinical decisions. Evaluation of hands-on interventions to protect women from severe perineal tears must include not just one outcome of interest, but also an assessment of how the intervention interferes with the normal mechanism of birth, and how it affects neonatal outcomes and the autonomy of women.

Is episiotomy worthwile to prevent obstetric anal sphincter injury during operative vaginal delivery in nulliparous women?

OBJECTIVES

Episiotomy is a marker of Obstetric Anal Sphincter Injury (OASIS) condition, therefore, unmeasured factors could have biased the strength of the association between episiotomy and reduced OASIS during Operative Vaginal Delivery (OVD). The aim of this study was to compare the OASIS rate during OVD according to episiotomy practice.

STUDY DESIGN

Retrospective cohort study of all nulliparous pregnant women attempting an OVD between 2014-2017. To avoid unmeasured bias, all maternal and delivery data were prospectively captured after the birth. The strong relationship between parity and episiotomy practice (indication bias) lead to analyze only nulliparous women. Association between mediolateral episiotomy and OASIS following OVD was performing by using multivariate logistic regression analysis including significant variable in univariate analysis and relevant factors known to be associated both with OASIS and/or OVD.

RESULTS

Over the study period, 1709 (17.1%) women had an OVD, among them 40 (2.3%) had OASIS. In the 1342 (78.5%) nulliparous women, OASIS rate were 2% and 5.1% with and without episiotomy (p < 0.01). In multivariate analysis a lower incidence of OASIS with the use of episiotomy (OR 0.267 IC 0.132-0.541) were observed. The persistent occiput posterior position was associated with an increase risk of OASIS (OR 6.742 IC 2.376-19.124). Spatula/forceps, as compared to vacuum operative vaginal delivery increased the risk OASIS (OR 2.847 IC 1.311-7.168). Area under the curve of the model was 0.745.

CONCLUSION

Episiotomy is a modifiable risk factors which can contribute to reduce the risk of OASIS in nulliparous women with operative vaginal delivery. This intervention should be included in a global management of the second stage of labor.

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.

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

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

Fetal head size and effect of manual perineal protection

OBJECTIVE

The aim of this study was to evaluate whether a previously identified modification of Viennese method of perineal protection remains most effective for reduction of perineal tension in cases with substantially smaller or larger fetal heads.

METHODS

A previously designed finite element model was used to compare perineal tension of different modifications of the Viennese method of perineal protection to "hands-off" technique for three different sizes of the fetal head. Quantity and extent of tension throughout the perineal body during vaginal delivery at the time when the suboccipito-bregmatic circumference passes between the fourchette and the lower margin of the pubis was determined.

RESULTS

The order of effectiveness of different modifications of manual perineal protection was similar for all three sizes of fetal head. The reduction of perineal tension was most significant in delivery simulations with larger heads. The final position of fingers 2cm anteriorly from the fourchette (y = +2) consistently remains most effective in reducing the tension. The extent of finger movement along the anterior-posterior (y-axis) contributes to the effectiveness of manual perineal protection.

CONCLUSION

Appropriately performed Viennese manual perineal protection seems to reduce the perineal tension regardless of the fetal head size, and thus the method seems to be applicable to reduce risk of perineal trauma for all parturients.

Active delivery of the anterior arm and incidence of second-degree perineal tears: a clinical practice evaluation

BACKGROUND

Evaluate the feasibility of active delivery of the anterior arm during spontaneous delivery. This maneuver could decrease incidence of second-degree perineal tears because it reduces fetal biacromial diameter.

METHODS

An observational comparative prospective study was conducted at our teaching maternity from July 2012 to March 2013. The study included 199 nulliparous women ≥18 years, who met the following criteria: singleton pregnancy, vaginal delivery with occiput anterior presentation, on epidural analgesia, from 37 weeks of gestation onward. The distribution of rate and type of perineal tears were compared between two groups: a non-exposed group and a group exposed to the maneuver.

RESULTS

A total of 101 patients were exposed to Couder's maneuver (CM) and 98 patients were not exposed. In the intervention group, 3 failures of the maneuver were reported. The maneuver was considered easy in 80% of cases, moderately easy in 12% and difficult in 8% of cases. There was a significant difference (p = 0.03) in the distribution of perineal tears between the two groups. There was a significant reduction (p < 0.001) in the number of second-degree perineal tears in the patients exposed to CM. There was no significant difference in the rate of anterior perineal trauma between the exposed and non-exposed arms.

CONCLUSIONS

CM in primiparous women at term is feasible with a low failure rate and influences the distribution of perineal tears by lowering second-degree perineal tears in a highly significant manner (p <0.01).

Perineal injuries and birth positions among 2992 women with a low risk pregnancy who opted for a homebirth

BACKGROUND

Whether certain birth positions are associated with perineal injuries and severe perineal trauma (SPT) is still unclear. The objective of this study was to describe the prevalence of perineal injuries of different severity in a low-risk population of women who planned to give birth at home and to compare the prevalence of perineal injuries, SPT and episiotomy in different birth positions in four Nordic countries.

METHODS

A population-based prospective cohort study of planned home births in four Nordic countries. To assess medical outcomes a questionnaire completed after birth by the attending midwife was used. Descriptive statistics, bivariate analysis and logistic regression were used to analyze the data.

RESULTS

Two thousand nine hundred ninety-two women with planned home births, who birthed spontaneously at home or after transfer to hospital, between 2008 and 2013 were included. The prevalence of SPT was 0.7 % and the prevalence of episiotomy was 1.0 %. There were differences between the countries regarding all maternal characteristics. No association between flexible sacrum positions and sutured perineal injuries was found (OR 1.02; 95 % CI 0.86-1.21) or SPT (OR 0.68; CI 95 % 0.26-1.79). Flexible sacrum positions were associated with fewer episiotomies (OR 0.20; CI 95 % 0.10-0.54).

CONCLUSION

A low prevalence of SPT and episiotomy was found among women opting for a home birth in four Nordic countries. Women used a variety of birth positions and a majority gave birth in flexible sacrum positions. No associations were found between flexible sacrum positions and SPT. Flexible sacrum positions were associated with fewer episiotomies.

Obstetric anal sphincter injury and incontinence 15-23 years after vaginal delivery

INTRODUCTION

The primary aim was to study prevalence of obstetric anal sphincter injuries (OASIS) after normal vaginal deliveries (NVD) and operative vaginal deliveries (OVD) with a subgroup analysis of forceps (FD) vs. vacuum deliveries (VD). The secondary aim was to study the association between OASIS and anal incontinence 15-23 years later.

MATERIAL AND METHODS

This was a cross-sectional study including 8137 primiparous women in Trondheim, Norway, from 1990 to 1997. The outcome measure was the adjusted odds ratio (aOR) for OASIS between delivery groups. A total of 1122 women responded to a postal questionnaire containing the Colorectal-Anal Distress Inventory (CRADI) in 2013. The aOR for anal incontinence and the difference in CRADI score between women with and without OASIS were calculated.

RESULTS

OASIS prevalence was 2% for NVD and 10% for OVD (10% FD, 9% VD). aOR for OASIS was 5.01 (95%CI 3.85-6.51) comparing OVD with NVD. There was no difference between FD and VD (aOR 1.15, 95% CI 0.79-1.67). FD was associated with higher risk of fourth degree perineal tear than VD (aOR 5.08, 95% CI 1.47-17.49). OASIS was associated with increased risk of leakage of well-formed (aOR 8.61, 95% CI 3.08-24.12) and loose stool (aOR 2.75, 95% CI 1.43-5.27) and higher CRADI score (Mann-Whitney U-test, p = 0.01).

CONCLUSIONS

OVD was associated with increased risk of OASIS. FD was associated with higher risk of fourth degree perineal tear compared with VD. OASIS was associated with increased risk of anal incontinence and higher CRADI score 15-23 years later.

Early pelvic floor muscle training after obstetrical anal sphincter injuries for the reduction of anal incontinence

OBJECTIVES

Between 0.5 and 5% of vaginal deliveries involve obstetrical anal sphincter injuries (OASIS). Thirty to forty percent of patients with OASIS will suffer from anal incontinence in the subacute postpartum period. The aim of the present study was to assess the effectiveness of early pelvic floor muscle training (PFMT) combined with standard rehabilitation on anal incontinence after vaginal deliveries complicated by OASIS.

STUDY DESIGN

The present work was a retrospective quantitative study performed in a tertiary-level maternity hospital. Women with 3rd or 4th degree obstetric tears were included. Women who gave birth between January 1st, 2011 and December 31st, 2012 underwent standard pelvic-perineal rehabilitation within 6-8 weeks postpartum. Women who gave birth between January 1st, 2013 and July 1st, 2014 had early rehabilitation (within 30 days after delivery) followed by the same standard rehabilitation received by the other group. Rehabilitation was performed by physiotherapists specialized in perineology. No electrostimulation was done in early rehabilitation. An in-house-validated modification of the Jorge and Wexner questionnaire was sent by mail to the patients to assess symptoms. The main judgment criterion was anal incontinence to gas, loose stools and/or solid stool.

RESULTS

Two hundred and thirty patients were diagnosed with OASIS. Nineteen women (8.3%) were lost to follow-up. The intention-to-treat analysis included 211 patients, 109 of whom underwent standard rehabilitation and 102 early rehabilitation plus standard rehabilitation. The two groups were comparable in terms of parity, birth weight, assisted delivery, epidural anesthesia and rates of mediolateral episiotomy. Multivariate analyses adjusted for type of perineal lesion were performed. Early rehabilitation significantly reduced gas leakage: OR 0.51 [0.29-0.90] (p=0.02), liquid stool leakage: OR 0.22 [0.08-0.58] (p=0.02) and urinary stress incontinence: OR 0.43 [0.24-0.77] (p=0.004).

CONCLUSIONS

We recommend early (during the first month postpartum) PFMT after vaginal deliveries associated with OASIS. Rehabilitation should be carried out by a physiotherapist specialized in perineology in order to prevent medium-term functional consequences. A longer follow-up may be necessary to confirm the stability of results.

Episiotomy preferences, indication, and classification--a survey among Nordic doctors

INTRODUCTION

Episiotomy performance impacts perineal health and rates of obstetric anal sphincter injuries (OASIS). Our objective was to assess self-reported episiotomy practice and opinions on clinical indication for episiotomy among Nordic physicians and to investigate potential misclassification.

MATERIAL AND METHODS

A survey was conducted among doctors attending the 2012 Nordic obstetrical and gynecological conference. Participants were asked to draw an episiotomy on a photo of a perineum with a crowning fetal head similarly to their clinical practice if an episiotomy was clinically indicated, and to name the technique drawn. Differences in outcome measures were compared by country of practice and seniority.

RESULTS

The majority of the 297 participants (47%) drew a lateral episiotomy according to our classification by incision point and angle, but as many as 64% of these 138 doctors misclassified this as mediolateral episiotomy. Only 20% drew a mediolateral episiotomy, the great majority classifying it accurately, but 8% misclassified their mediolateral cut as a lateral episiotomy. One-third of episiotomies were nonclassifiable. In general, doctors in Finland, Sweden, and Norway more often favored lateral episiotomies compared with doctors in Denmark and Iceland. There were significant differences between Finnish and Norwegian vs. Danish and Swedish doctors in perception of clinical indications for episiotomy.

CONCLUSIONS

The great variation in self-reported episiotomy performance between Nordic physicians and large misclassification rates indicate that educational programs are warranted. Use of uniform classification and appropriate techniques may be crucial to investigate the role of episiotomies in preventing OASIS.

Perineal and vaginal tears are clinical markers for occult levator ani trauma: a retrospective observational study

OBJECTIVES

Levator avulsion has been shown to be associated with anterior and central compartment prolapse and is a risk factor for prolapse recurrence. Diagnosis in the delivery room is usually impossible, as levator avulsion is commonly occult. The objective of this study was to determine if vaginal and major perineal tears are clinical markers of levator trauma as diagnosed by four-dimensional (4D) translabial ultrasound 3-6 months postpartum.

METHODS

This was a retrospective observational study using data obtained in two perinatal trials. A total of 774 women seen, on average, 5 (range, 2.3-22.4) months after their first delivery of a term singleton cephalic baby underwent a standardized interview, clinical assessment and 4D translabial ultrasound examination. Clinical data were obtained from the institutional obstetric database, including information on vaginal and perineal tears. Levator avulsion was diagnosed using tomographic ultrasound, with operators blinded to the clinical data.

RESULTS

Both third- and fourth-degree perineal tears and vaginal sidewall tears were independently associated with levator avulsion (P = 0.004 and P = 0.012, respectively). The odds ratio for avulsion in women suffering from such overt trauma was 3.44 (95% CI, 1.47-8.03) for third-/fourth-degree perineal tears and 3.35 (95% CI, 1.30-8.61) for vaginal sidewall tears.

CONCLUSIONS

Vaginal sidewall and third-/fourth-degree perineal tears were found to be independent clinical indicators of an increased risk of levator trauma, as diagnosed by 4D translabial ultrasound 3-6 months postpartum. Such clinical markers may become useful in the identification of women at high risk of levator trauma and future pelvic floor disorders.

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

Objectives

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

Data sources

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

Methods of study selection

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

Tabulation, integration and results

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

Conclusion

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

Electronic supplementary material

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

Risk factors for obstetric anal sphincter injury: To prolong or to vacuum?

INTRODUCTION

An awareness of risk factors for obstetric anal sphincter injuries (OASIS) is essential in order to reduce the occurrence of the primary event. These risk factors are demographic, obstetric and intrapartum related. We aimed to identify the risk factors for OASIS and to examine how modifiable risk factors may be used in order to reduce the incidence of OASIS.

METHODS

A retrospective, matched case-control study was conducted in the delivery ward of a single university teaching hospital in Israel, using data from January 2004 to July 2012. All singleton vaginal deliveries at term with OASIS were included. The controls included women matched at a ratio of 1:2 based on gestational age and deliveries that occurred immediately before and after the delivery of the women in the study group.

RESULTS

Overall, 113 OASIS were identified. Stepwise conditional logistic regression revealed that the first vaginal birth (OR = 7.6; 95% confidence interval (CI), 3.5-16.3; p < 0.001) particularly after a previous caesarean section (OR = 13.6; 95% CI, 4.7-39.3; p < 0.001) and the length of the second stage (OR 1.5; 95% CI, 1.1-2.1, p = 0.045) were the only risk factors for OASIS. Among 24 primiparous women who already had a prolonged second stage, 15 delivered by vacuum extraction and nine spontaneously; OASIS occurred in eight (53%) and three (33%) women, respectively. Multivariate analysis showed that this difference was not significant (OR = 2.3; 95% CI, 0.4-12.7; p = 0.35).

CONCLUSIONS

The first vaginal birth particularly after a caesarean delivery and the length of the second stage increased the risk of OASIS. Vacuum extraction performed to shorten a prolonged second stage is not necessarily protective.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Does the Finnish intervention prevent obstetric anal sphincter injuries? A systematic review of the literature

OBJECTIVES

A rise in obstetric anal sphincter injuries (OASIS) has been observed and a preventive approach, originating in Finland, has been introduced in several European hospitals. The aim of this paper was to systematically evaluate the evidence behind the 'Finnish intervention'.

DESIGN

A systematic review of the literature conducted according to the Preferred Reporting for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

OUTCOME MEASURES

The primary outcome was OASIS. Secondary outcomes were (perinatal): Apgar scores, pH and standard base excess in the umbilical cord, and (maternal): episiotomy, intact perineum, first and second-degree perineal lacerations, duration of second stage, birth position and women's perceptions/birth experiences.

METHODS

Multiple databases (Cochrane, Embase, Pubmed and SveMed) were systematically searched for studies published up to December 2014. Both randomised controlled trials and observational studies were eligible for inclusion. Studies were excluded if a full-text article was not available. Studies were evaluated by use of international reporting guidelines (eg, STROBE).

RESULTS

Overall, 1042 articles were screened and 65 retrieved for full-text evaluation. Seven studies, all observational and with a level of evidence at 2c or lower, were included and consistently reported a significant reduction in OASIS. All evaluated episiotomy and found a significant increase. Three studies evaluated perinatal outcomes and reported conflicting results. No study reported on other perineal outcomes, duration of the second stage, birth positions or women's perceptions.

CONCLUSIONS

A reduction in OASIS has been contributed to the Finnish intervention in seven observational studies, all with a low level of evidence. Knowledge about the potential perinatal and maternal side effects and women's perceptions of the intervention is extremely limited and the biological mechanisms underlying the Finnish intervention are not well documented. Studies with a high level of evidence are needed to assess the effects of the intervention before implementation in clinical settings can be recommended.

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

OBJECTIVE

To determine whether rates of obstetric anal sphincter injuries (OASIS) are continuing to increase and whether risk of OASIS according to mode of delivery is constant over time.

METHODS

In a retrospective population-based study, data were obtained for vaginal singleton vertex deliveries at 37-41 weeks of pregnancy among primiparous women in New South Wales, Australia, between January 2001 and December 2011. Annual OASIS rates were determined among non-instrumental, forceps, and vacuum deliveries with and without episiotomy. Multivariable logistic regression was used to determine adjusted odds ratios for each delivery mode category by year. Trends in adjusted odds ratios over time for each delivery category were compared.

RESULTS

OASIS occurred in 955 (4.1%) of 23 081 deliveries in 2001 and 1487 (5.9%) of 25 081 deliveries in 2011. After adjustment for known risk factors, the only delivery categories to show statistically significant increases in OASIS over the study period were non-instrumental deliveries without episiotomy (linear trend P<0.001) and forceps deliveries with episiotomy (linear trend P=0.004).

CONCLUSION

Overall, OASIS rates have continued to increase. Known risk factors do not fully explain the increase in OASIS rates in non-instrumental deliveries without an episiotomy and in forceps deliveries with an episiotomy.

Perineal management techniques among midwives at five hospitals in New South Wales - a cross-sectional survey

BACKGROUND

Midwives are reported to have changed from 'hands on' to 'hands poised or off' approaches to birth at the same time as obstetric anal sphincter injuries (OASIs) are increasing. As perineal management details are not routinely collected, it is difficult to quantify practice.

AIMS

To determine which perineal protections techniques midwives prefer for low-risk non-water births; whether preference is associated with technique taught or with other characteristics; and whether midwives change preference according to clinical scenario.

MATERIALS AND METHODS

Midwives in Northern Sydney Local Health District (NSLHD) were surveyed during a 2-week period in 2014. Multiple-choice questions were used, with free text option. Descriptive analyses, chi-square and McNemar tests were undertaken.

RESULTS

One hundred and eight midwives participated (response rate 76.7%). 'Hands poised or off' was preferred by 63.0% for a low-risk birth. Current practice was associated with technique taught (P < 0.01). For scenarios with increased OASI risk midwives reported switching to 'hands on', with 83.4% employing 'hands on' whether there was concern about an impending OASI. There has been a shift over time from teaching 'hands on' to 'hands poised or off'.

CONCLUSION

The preferred technique for a low-risk birth appears to have changed from 'hands on' to 'hands poised or off', but most midwives adopt 'hands on' in situations of high risk for OASI. Further research is needed to establish whether there is an association with the rising OASI rate and the change in preferred perineal management technique for a low-risk birth.

A perineal protection device designed to protect the perineum during labor: a multicenter randomized controlled trial

OBJECTIVE

The objective of this study was to evaluate the protective effects of a new device for reducing perineal tears during vaginal childbirth.

STUDY DESIGN

A multicenter open randomized controlled trial (RCT) was performed in Helsingborg, Lund and Malmö, Sweden consisting of 1148 women. Women anticipating a vaginal delivery were either randomized to the intervention group (n=574 in which the perineal protection device was used, or a control group (n=574), in which the perineal protection device was not used. The main outcome measurements were incidence of vaginal and perineal tears (1st to 4th degree tears) and adverse effects on the parturient and newborn.

RESULTS

The incidences of first- and second-degree tears of the vagina (p=0.018) and perineum (p=0.005) were significantly reduced in the intervention group compared with the controls. In the intervention- and control group, 184 women (34.9%) and 142 (26.6%) showed no perineal tearing, respectively (p=0.034). Numbers needed to treat to avoid any perianal tearing was 12. The incidence of anal sphincter rupture (ASR) was the same in both groups (n=19; 3.4%). No negative effects on mother or child from using the device were observed.

CONCLUSIONS

The perineal protective device significantly reduced the incidence of first- and second-degree tears in the vagina and perineum during vaginal birth and also significantly increased the number of parturients with a fully intact posterior commissure. No significant reduction of ASR and no negative effects of the device were observed.

The effect of primary delivery of the anterior compared with the posterior shoulder on perineal trauma: a study protocol for a randomized controlled trial

BACKGROUND

Approximately 85% of vaginal deliveries are accompanied by perineal trauma. The objective of this trial is to compare the incidence and degree of perineal trauma after primary delivery of the anterior compared with the posterior shoulder during vaginal birth. The hypothesis is that primary delivery of the posterior shoulder reduces the rate and degree of perineal trauma.

METHODS/DESIGN

This is a single-centre, randomized controlled trial, with computer-generated randomization in a 1:1 allocation ratio. Women planning their first vaginal delivery (n = 650) are randomized to primary delivery of either the anterior or posterior shoulder. The primary outcome is any perineal trauma. Additional outcomes are the perineal injury subtypes, postpartum bleeding, umbilical artery pH, Apgar score at 5 minutes and any neonatal birth trauma. Perineal trauma is assessed by a midwife or doctor blinded to the method of shoulder delivery. All midwives are trained in the two methods of shoulder delivery and in the grading of perineal tears. The trial is being undertaken at a Danish community hospital with 1,600 yearly deliveries. Data will be analyzed according to the intention-to-treat principle. Recruitment started in January 2013 and the trial is planned to proceed for 24 months.

DISCUSSION

Most delivery assistance techniques are based on tradition and heritage and lack objective evidence. This trial provides an example of how vaginal delivery techniques can be evaluated in a randomized controlled trial. The results of this trial will clarify the role that delivery of the shoulders has on perineal trauma and thereby provide knowledge to recommendations on birthing technique.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01937546.