A Multicenter Interventional Program to Reduce the Incidence of Anal Sphincter Tears

Minimizing tearing during vaginal delivery with a perineal protection device: a randomized controlled trial

BACKGROUND

There is a growing body of evidence indicating that second-degree tears cause both short- and long-term consequences. Very few preventative measures have been found to reduce the incidence of these tears.

OBJECTIVE

This study aimed to investigate whether the use of a perineal protection device during vaginal birth reduces severe perineal tearing (grade ≥2 tear) in primiparous women compared with routine manual perineal support.

STUDY DESIGN

A single-center randomized controlled trial was conducted in Sweden from 2019 to 2021. Primiparous women at term were randomly allocated to the intervention group (n=43), where a perineal protection device was used, or to the routine care group (n=49). The primary outcome was grade of perineal tear. The secondary outcomes were vaginal and labial tearing. Continuous data were analyzed using the Student t test or Mann-Whitney U test. Dichotomous data were analyzed using the Pearson X2 test, Fisher exact test, and ordinal logistic regression.

RESULTS

Women in the intervention group had a significantly lower risk of sustaining more extensive perineal tearing than those in the control group. The use of the perineal protection device decreased the risk of grade ≥2 tears in relation to grade 0 to 1 tears (odds ratio, 0.40; 95% confidence interval, 0.17-0.94). Ordinal logistic regression analyses revealed an odds ratio of 0.36 (95% confidence interval, 0.16-0.81) per incremetn of grade injury using the perineal protection device vs routine care (P=.013). The number needed to treat using the perineal protection device was 4.3 to avoid 1 grade ≥2 tear. Women in the treatment group showed less labial tearing (P=.016). No adverse effect was detected.

CONCLUSION

The use of a perineal protection device reduced the risk of grade ≥2 perineal tearing by 60% and labial tearing. El resumen está disponible en Español al final del artículo.

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.

Perineal injuries during vaginal birth in low-resource countries

Birth related perineal trauma (BRPT) and obstetric anal sphincter injuries (OASIS) are leading causes of anal incontinence in women, which negatively impacts on their quality of life, resulting in low self-esteem and abandonment. In low resource countries (LRC), the true incidence is not known and since most births are unattended or occur in community-based health care systems, one can anticipate that it is a significant problem. Dissemination of information to women, education of traditional birth attendants, improvement of resources and transport, and training of health professionals on the detection and appropriate surgical management of these injuries will reduce morbidity and improve outcome. Intrapartum measures such as controlled head descent and perineal support, correct episiotomy techniques and selective use of instruments to assist vaginal births is pivotal in avoiding these injuries. Policy makers should prioritize maternity care in LRC, and research is urgently needed to address all aspects of BRPT.

Variability of clinical practice in the care of the second stage of labor among midwives in Spain

BACKGROUND

There are recommendations based on scientific evidence on care in the second stage of labor, but it is not known to what degree the professionals comply with these recommendations.

OBJECTIVE

The aim of this study is to examine the variability in clinical practices among midwives during the second stage of labor, including positions, mobility, practices, and the maximum time allowed before initiating active pushing, and to assess their adherence to clinical practice guidelines.

METHODS

A cross-sectional observational study. A self-designed questionnaire was developed and distributed online through scientific societies. The main variables studied were professional and work environment characteristics, maternal positions and mobility, practices during this stage, maximum time to start active pushing and duration of the second stage of labor. Descriptive statistics were calculated using SPSS 24.0.

RESULTS

Regarding the woman's position during childbirth, 80.3% (245) of midwives frequently or always allow the woman to choose her birthing position. Furthermore, 44.6% (136) of professionals prefer using side-lying positions for the mother. Regarding drinking fluids during childbirth, 51.1% (156) of midwives allowed the woman to drink the amount of liquids she wanted, whereas 11.1% (34) said that they would allow them to do so however, this was against the protocol of their hospital. When inquiring about the Kristeller maneuver, it was reported to be excessively performed in 35.1% (107) of cases for fetal bradycardia, 33.1% (101) for maternal exhaustion, and 38.4% (117) to avoid instrumental birth. Finally, a great variability was observed in the time criteria used for the initiation of active pushing and the maximum duration of the second stage of labor.

CONCLUSIONS

Certain practices, such as the Kristeller maneuver, are overused among midwives, with great variability in the use of certain procedures, the waiting times to initiate pushing and completion of the second stage of labor. Further training and awareness campaigns are needed for professionals to apply evidence-based care.

The prevention of perineal trauma during vaginal birth

Perineal trauma after vaginal birth is common, with approximately 9 of 10 women being affected. Second-degree perineal tears are twice as likely to occur in primiparous births, with a incidence of 40%. The incidence of obstetrical anal sphincter injury is approximately 3%, with a significantly higher rate in primiparous than in multiparous women (6% vs 2%). Obstetrical anal sphincter injury is a significant risk factor for the development of anal incontinence, with approximately 10% of women developing symptoms within a year following vaginal birth. Obstetrical anal sphincter injuries have significant medicolegal implications and contribute greatly to healthcare costs. For example, in 2013 and 2014, the economic burden of obstetrical anal sphincter injuries in the United Kingdom ranged between £3.7 million (with assisted vaginal birth) and £9.8 million (with spontaneous vaginal birth). In the United States, complications associated with trauma to the perineum incurred costs of approximately $83 million between 2007 and 2011. It is therefore crucial to focus on improvements in clinical care to reduce this risk and minimize the development of perineal trauma, particularly obstetrical anal sphincter injuries. Identification of risk factors allows modification of obstetrical practice with the aim of reducing the rate of perineal trauma and its attendant associated morbidity. Risk factors associated with second-degree perineal trauma include increased fetal birthweight, operative vaginal birth, prolonged second stage of labor, maternal birth position, and advanced maternal age. With obstetrical anal sphincter injury, risk factors include induction of labor, augmentation of labor, epidural, increased fetal birthweight, fetal malposition (occiput posterior), midline episiotomy, operative vaginal birth, Asian ethnicity, and primiparity. Obstetrical practice can be modified both antenatally and intrapartum. The evidence suggests that in the antenatal period, perineal massage can be commenced in the third trimester of pregnancy to increase muscle elasticity and allow stretching of the perineum during birth, thereby reducing the risk of tearing or need for episiotomy. With regard to the intrapartum period, there is a growing body of evidence from the United Kingdom, Norway, and Denmark suggesting that the implementation of quality improvement initiatives including the training of clinicians in manual perineal protection and mediolateral episiotomy can reduce the incidence of obstetrical anal sphincter injury. With episiotomy, the International Federation of Gynecology and Obstetrics recommends restrictive rather than routine use of episiotomy. This is particularly the case with unassisted vaginal births. However, there is a role for episiotomy, specifically mediolateral or lateral, with assisted vaginal births. This is specifically the case with nulliparous vacuum and forceps births, given that the use of mediolateral or lateral episiotomy has been shown to significantly reduce the incidence of obstetrical anal sphincter injury in these groups by 43% and 68%, respectively. However, the complications associated with episiotomy including perineal pain, dyspareunia, and sexual dysfunction should be acknowledged. Despite considerable research, interventions for reducing the risk of perineal trauma remain a subject of controversy. In this review article, we present the available data on the prevention of perineal trauma by describing the risk factors associated with perineal trauma and interventions that can be implemented to prevent perineal trauma, in particular obstetrical anal sphincter injury.

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.

A systematic review and a meta-analysis on the incidence of obstetric anal sphincter injuries during vaginal delivery

AIM

The incidence of obstetric anal sphincter injuries (OASIS) has increased in the past two decades despite improved awareness of the risk factors. This study aimed to define the incidence of OASIS in women with different features (instrumental delivery or other variables).

METHODS

A systematic review was conducted on articles reporting the incidence of OASIS. This review aims to examine the association of instrumentation and OASIS by performing a formal systematic review of the published literature. Databases used for the research were MEDLINE, Embase, CINAHL and 'Maternity and infant care' databases.

RESULTS

Two independent reviewers screened the selected articles. 2326 duplicates were removed from the total of 4907 articles. The remaining 2581 articles were screened for title and abstract. 1913 articles were excluded due to irrelevance. The remaining 300 were screened as full text. Primiparity associated with the use of forceps were the features associated with the highest incidence of OASIS in the selected articles (19.4%). OASIS in all women had an overall incidence of 3.8%. The incidence of OASIS in all women by geographical region was the highest (6.5%) in North America.

CONCLUSIONS

There are various factors that impact on the incidence of OASIS and the combination of some of these, such as the use of forceps in primiparas, resulted in the highest incidence of OASIS. The lack of international consensus is limiting the improvements that can be done to reduce OASIS rates and improve best clinical practice.

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

Background

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

Methods

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

Results

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

Conclusions

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

Neonatal head circumference as a risk factor for obstetric anal sphincter injuries: a systematic review and meta-analysis

OBJECTIVE

Between 53% and 79% of women will sustain some degree of perineal laceration during vaginal delivery. Third- and fourth-degree perineal lacerations are known as obstetric anal sphincter injuries. Timely diagnosis and prompt treatment of obstetric anal sphincter injuries can help to prevent the development of severe consequences like fecal incontinence, urinary incontinence, and rectovaginal fistula. Neonatal head circumference is routinely measured postpartum but is often not mentioned as a risk factor for obstetric anal sphincter injuries in clinical guidelines. Thus far, no review article on the risk factors for obstetric anal sphincter injuries has discussed the role of neonatal head circumference. This study aimed to review and analyze the relationship between head circumference and the occurrence of obstetric anal sphincter injuries among previous studies to conclude whether head circumference should be recognized as an important risk factor.

DATA SOURCES

Through study screening on Google Scholar, PubMed, Scopus, and Science Direct for articles published between 2013 to 2023, followed by assessment of eligibility, this study ended up reviewing 25 studies, 17 of which were included in the meta-analysis.

STUDY ELIGIBILITY CRITERIA

Only studies that reported both the neonatal head circumference and the occurrence of obstetric anal sphincter injuries were included in this review.

METHODS

The included studies were appraised using the Dartmouth Library risk of bias assessment checklist. Qualitative synthesis was based on the study population, findings, adjusted confounding factors, and suggested causative links in each study. Quantitative synthesis was conducted using calculation and pooling of odds ratios and inverse variance using Review Manager 5.4.1.

RESULTS

A statistically significant association between head circumference and obstetric anal sphincter injuries was reported in 21 of 25 studies; 4 studies reported that head circumference was a true independent risk factor. A meta-analysis of the studies that reported neonatal head circumference as a dichotomous categorical variable with a cutoff point of 35±1 cm yielded statistically significant pooled results (odds ratio, 1.92; 95% confidence interval, 1.80-2.04).

CONCLUSION

The risk for obstetric anal sphincter injuries increased as the neonatal head circumference increased-this should be considered in decision-making during labor and postpartum management to attain the best outcome.

Effect of the "shoulder-up" bundle on the incidence of spontaneous perineal injury after vaginal delivery: comparison of 2 historic cohorts after propensity score matching

BACKGROUND

Perineal injury following vaginal delivery represents a major cause of long-term maternal morbidity, and its prevention is among the priorities of modern obstetrical practice.

OBJECTIVE

This study aimed to investigate whether the systematic implementation of a bundle of maneuvers to prevent perineal injury (ie, the "shoulder-up" bundle) may reduce the rate of spontaneous perineal tears in women delivering at a single tertiary maternity unit.

STUDY DESIGN

This was a single-center retrospective intervention study including all vaginal deliveries between April 1, 2020 and March 31, 2022. On March 1, 2021, a bundle focused on perineal injury prevention in vaginal deliveries was implemented and introduced as a standard of care. The "shoulder-up" bundle includes the addition of a hands-on technique for the delivery of the posterior shoulder, which is slowly lifted up under the direct visualization of the perineal body, immediately after the disengagement of the anterior shoulder. The labor ward staff underwent dedicated training to acquire expertise on the "shoulder-up" bundle. Little changes in terms of medical and midwifery staffing were recorded during the study period. The incidence of spontaneous second-degree or higher perineal tears was compared between the patients who gave birth before the clinical implementation of the bundle (standard-care group) and those who were delivered following the implementation of the bundle (shoulder-up group). A 1:1 propensity score matching of the 2 groups was done for the variables that proved to be independently associated with the perineal outcome.

RESULTS

From April 1, 2020 to March 31, 2022, 3671 patients had a vaginal birth at our tertiary care unit (1786 in the standard-care group and 1885 in the "shoulder-up" group) and were enrolled in the study population. Of these, 1191 (32.4%) had a spontaneous second-degree or higher perineal tear. At univariate analysis, nulliparity (59.6% vs 39.1%; P<.001), higher gestational age at delivery (39.8±1.28 vs 39.4±1.97 weeks; P<.001), epidural analgesia (40.6% vs 31.2%; P<.001), vacuum-assisted delivery (9.6% vs 4.0%; P<.001), and birthweight >4 kg (11.0% vs 6.3%; P<.001) were independently associated with the perineal outcome. Following propensity score matching for the above cited factors, the 1703 patients of each group were compared. A significant increase in the rate of intact perineum (71.0% vs 64.1%; P=.014) and a reduction in the incidence of second- (27.2% vs 32.9%; P=.006) and third to fourth-degree perineal tears (1.3% vs 3.0%; P<.001) was demonstrated in the "shoulder-up" group. Among the subgroup of patients undergoing vacuum-assisted delivery, a borderline significant reduction in the rate of obstetrical anal sphincter injury (10.4% vs 2.9%; P=.052) was also observed.

CONCLUSION

Our study showed that the clinical implementation of the "shoulder-up" bundle at vaginal delivery is associated with a significant reduction in the incidence of spontaneous second-degree or higher perineal tears.

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.

Obstetric anal sphincter injuries-Maternal, fetal and sociodemographic risk factors: A retrospective register-based study

INTRODUCTION

Obstetric anal sphincter injuries (OASIS) are severe complications to vaginal births with potentially serious long-term consequences and large impact on quality of life. The aim was to determine risk and protective factors for OASIS.

MATERIAL AND METHODS

We performed a retrospective register-based observational study. A cohort of 988 988 singleton term deliveries 2005-2016 in Sweden were included. Data from the Swedish Medical Birth Registry and Statistics Sweden were extracted to identify cases of OASIS and maternal and fetal characteristics. Modified Poisson Regression analyses were performed to assess risk factors.

RESULTS

The rate of OASIS was 3.5% (n = 34 583). Primiparity (adjusted risk ratio [aRR] 3.13, 95% CI 3.05-3.21), vacuum extraction (aRR 2.79, 95% CI 2.73-2.86), forceps (aRR 4.27, 95% CI 3.86-4.72), and high birthweight (aRR 2.61, 95% CI 2.50-2.72) were associated with a significantly increased risk of OASIS. Increasing maternal age and decreasing maternal height also increased the risk of OASIS. Obesity increased the risk of OASIS (aRR 1.04, 95% CI 1.04-1.08), if fetal birthweight was not adjusted for. Smoking (aRR 0.74, 95% CI 0.70-0.79) and low maternal education (aRR 0.87, 95% CI 0.83-0.92) were associated with a decreased frequency of reported OASIS. Previous cesarean section increased the risk of OASIS (aRR 1.41, 95% CI 1.36-1.47).

CONCLUSIONS

Primiparity, instrumental delivery, and high birthweight significantly increased the risk of OASIS. Obesity, low height, increasing age, and previous cesarean section also increased the risk whereas smoking and low maternal educational level were associated with a lower OASIS rate.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

KEY POINTS

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

3rd and 4th degree perineal tears that occurs during vaginal delivery

Objective: Perineal injuries are common in vaginal delivery. In this study, we aimed to investigate the factors affecting the degree of perineal injury and the effect of injury degree on incontinence. Methods: Fifteen patients, underwent sphincter repair by the general surgery unit, who had perineal tear during normal vaginal delivery between January 2018 and March 2019 in our hospital and were retrospectively evaluated. Those with grade 3a and 3b perineal tears were divided into 2 groups as group-1, and those with grade 3c and grade 4 perineal tears as group-2. Episiotomy type, fetal characteristics [head circumference and birth weight], early postoperative continence findings were compared in between groups. Results: The average age of the patients was 30 ± 8.7 years. When the groups were compared, there was no significant superiority of episiotomy in terms of perineal injury (p=0.07). 4 patients had 3a, 3 patients had 3b, 6 patients had 3c and 2 patients had fourth-degree perineal injuries. The average birth weight of the newborns was 3438 ± 492 g, and the head circumference was 34.33 ± 1.23 cm. There was no significant difference in incontinence between the groups (p=0.55). Conclusıon: The treatment of anorectal injuries is surgery. The method of treatment varies according to the time elapsed between injury and intervention, fecal contamination, degree of injury, general condition of the patient, presence of accompanying injury, experience and preference of surgeon. We think that sphincter damage during delivery can be looked after successfully with early diagnosis and intervention before tissue edema develops.

Modifiable and non-modifiable risk factors for obstetric anal sphincter injury in a Norwegian Region: a case-control study

Background

Obstetric anal sphincter injury (OASI) is a common and severe complication of vaginal delivery and may have short- and long-term consequences, including anal incontinence, sexual dysfunction and reduced quality of life. The rate of OASI varies substantially between studies and national birth statistics, and a recent meta-analysis concluded that there is a need to identify unrecognized risk factors. Our aim was therefore to explore both potential modifiable and non-modifiable risk factors for OASI.

Methods

We performed a case–control study in a single center maternity clinic in South-Eastern Norway. Data were extracted retrospectively from an institutional birth registry. The main outcome measure was the occurrence of the woman’s first-time 3^rd or 4^th degree perineal lesion (OASI) following singleton vaginal birth after 30 weeks’ gestation. For each woman with OASI the first subsequent vaginal singleton delivery matched for parity was elected as control. The study population included 421 women with OASI and 421 matched controls who gave birth during 1990–2002. Potential risk factors for OASI were assessed by conditional logistic regression analyses.

Results

The mean incidence of OASI was 3.4% of vaginal deliveries, but it increased from 1.9% to 5.8% during the study period. In the final multivariate regression model, higher maternal age and birthweight for primiparous women, and higher birthweight for the multiparous women, were the only non-modifiable variables associated with OASI. Amniotomy was the strongest modifiable risk factor for OASI in both primi- (odds ratio [OR] 4.84; 95% confidence interval [CI] 2.60–9.02) and multiparous (OR 3.76; 95% CI 1.45–9.76) women, followed by augmentation with oxytocin (primiparous: OR 1.63; 95% CI 1.08–2.46, multiparous: OR 3.70; 95% CI 1.79–7.67). Vacuum extraction and forceps delivery were only significant risk factors in primiparous women (vacuum: OR 1.91; 95% CI 1.03–3.57, forceps: OR 2.37; 95% CI 1.14–4.92), and episiotomy in multiparous women (OR 2.64; 95% CI 1.36–5.14).

Conclusions

Amniotomy may be an unrecognized independent modifiable risk factor for OASI and should be further investigated for its potential role in preventive strategies.

Mediolateral episiotomy and risk of obstetric anal sphincter injuries and adverse neonatal outcomes during operative vaginal delivery in nulliparous women: a propensity-score analysis

Background

The potential protective effect of mediolateral episiotomy for obstetrical anal sphincter injuries (OASIs) remains controversial during operative vaginal delivery because of the difficulties to take into account the risk factors and clinical conditions at delivery; in addition, little is known about the potential benefits of mediolateral episiotomy on neonatal outcomes.

The objectives were to investigate the associations between mediolateral episiotomy and both OASIs and neonatal outcomes, using propensity scores.

Methods

We performed a retrospective population-based observational study from a perinatal registry that includes all births in a French region between 2010 and 2017. All nulliparous women with singleton pregnancy delivering by operative vaginal deliveries at 37 weeks gestational age or later were included. Inverse-probability-of-treatment weighting with propensity scores was used to minimize indication bias. OASIs was defined as third and fourth-degree tears according to Royal College of Obstetricians and Gynecologists. Two neonatal outcomes were studied: condition at birth (5-min Apgar score less than 7 and/or umbilical artery pH less than 7.10), and admission to neonatal intensive care unit.

Results

The study population consisted of 7589 women; 2880 (38.0%) received mediolateral episiotomy. After applying propensity scores, episiotomy was associated with a lower rate of OASIs in forceps/spatula delivery (2.3 vs 6.8%, Risk Ratio (RR) 0.38, 95% Confidence Interval (CI) 0.28–0.52) and in vacuum delivery (1.3 vs 3.4%, RR 0.27, 95% CI 0.20–0.38) as compared with no episiotomy. Mediolateral episiotomy was associated with better condition at birth in case of forceps/spatula delivery (4.5 vs 8.8%, RR 0.56, 95% CI 0.39–0.81). In cases of fetal distress (40.7%), mediolateral episiotomy was associated with better condition of infant at birth in women who delivered by forceps/spatula (4.2 vs 13.5%, RR 0.52, 95% CI 0.31–0.89). No association was found with neonatal unit admission (RR 0.93, 95% CI 0.50–1.74).

Conclusions

Use of mediolateral episiotomy was associated with a lower rate of OASIs during operative vaginal delivery, and in infants it was associated with better condition at birth following forceps/spatula delivery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04396-6.

Decreasing the incidence of anal sphincter tears in instrumental delivery in Hudiksvall, Sweden

PURPOSE

The primary aim of this study was to observe the change in obstetric anal sphincter tear rates in instrumental deliveries during one decade. Secondly, the changes in non-instrumental deliveries were followed.

METHODS

Data from all deliveries at Hudiksvall Hospital, Sweden 2010-2011 and 2016-2017 were collected. The change of OASIS rate during instrumental deliveries was the most important. Statistical significances were calculated by using chi-square test, test for relative proportions, and Students t-test, where appropriate.

RESULTS

The total incidence of OASIS decreased significantly (from 2.54% to 0.73%, p < .001). Even the OASIS rate in instrumental deliveries decreased substantially from 15.1% to 3.0% (p = .002) but the decrease was statistically insignificant in spontaneous deliveries (from 1.22% to 0.60%, p = .065).

CONCLUSION

Based on the results of our study the manual protection of the perineum reduces the risk of OASIS in instrumental delivery significantly.

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.

Perineal trauma in nulliparous women and its associated factors

Introduction: Perineal trauma is an important complication for women after giving birth. Objective: To evaluate the prevalence of perineal trauma and its associated factors in nulliparous. Methods: A retrospective cohort study was carried out, through the analysis of the medical records of women with singleton pregnancy who achieved vaginal birth of a live infant, in 2017, in a maternity hospital. Data collection involved information about demographic, obstetric, and clinical data from nulliparous women, and infant birthweight. Univariate and multivariate logistic analyses were performed to verify the association of perineal trauma with the variables assessed, with significant variables remaining in the model (p<0.05), through a stepwise strategy. Results: A total of 326 medical records were analyzed. The percentage of perineal trauma was 60%. In the multivariate analysis, the use of oxytocin increased the chance of perineal trauma by 730%. In addition, the adoption of squatting position and hands and knees decreased the chances of perineal trauma by 81% and 97%, respectively, in comparison with those who adopted the lithotomy position, during the second stage labor. Conclusion: The rate of perineal laceration was high, but the severity was low. The use of oxytocin is associated with the presence of trauma and the squatting position and hands and knees, especially, have contributed to the protection of the perineum.

Temporal trends in obstetric anal sphincter injury from the first vaginal delivery in Austria, Canada, Norway, and Sweden

INTRODUCTION

Obstetric anal sphincter injuries (OASI) are severe complications that can cause considerable short- and long-term morbidity. Austria, Canada, Norway, and Sweden have similar socio-economic characteristics, and all four countries have access to national birth registers. In this study, we hypothesized that the incidence of OASI should be very similar for different obstetric scenarios in these four countries. Therefore, the aim was to compare the incidence of OASI in these four countries in primiparous women, with spontaneous or instrumental delivery (vacuum or forceps), and in women with a first vaginal birth after cesarean section (VBAC).

MATERIAL AND METHODS

Aggregated data on 1 933 930 vaginally delivered primiparous women and women with VBAC were retrieved from the birth registers gathered in Austria, Canada, Norway, and Sweden. The annual rate of OASI (ICD-10 codes O70.2-O70.3) was presented as the percentage of women with a spontaneous delivery, vacuum or forceps delivery, and a VBAC during the period 2004-2016.

RESULTS

The incidence of OASI varied considerably between countries and over time. Canada and Sweden had the highest rates, and Austria and Norway the lowest. In Norway, the rate of OASI decreased consistently for all types of deliveries after introducing a perineal protection program in 2004 (p < 0.001). During vacuum delivery, the incidence of OASI varied between countries from 4.1% to 15.5% across the study period. In Canada and Norway, the rate of OASI after a forceps delivery was similar in 2004 at ~20% and with differing trajectories to 24.3% (β 0.49) and 6.2% (β -1.15) (trend, all p < 0.001) in 2016.

CONCLUSIONS

This comparative register study suggests that there may be considerable potential for lowering the incidence of OASI. The perineal protection program implemented by Norway has been successful. Each country should critically, without prejudice, analyze their current clinical practices and rate of OASI and consider the best preventive strategy.

The OASI care bundle quality improvement project: lessons learned and future direction

Rising rates of obstetric anal sphincter injury (OASI) led to a collaborative effort by the Royal College of Obstetricians and Gynaecologists (RCOG) and the Royal College of Midwives (RCM) to develop and evaluate the OASI Care Bundle (OASI-CB). The OASI-CB comprises four practices (antenatal discussion about OASI, manual perineal protection, mediolateral episiotomy at 60° from the midline, and systematic examination of the perineum, vagina and ano-rectum after vaginal birth) and was initially implemented as part of a quality improvement (QI) project—“OASI1”—in 16 maternity units across Great Britain. Evaluation of the OASI1 project found that the care bundle reduced OASI rates and identified several barriers and enablers to implementation. This paper summarises the key findings, including strengths, limitations and lessons learned from the OASI1 QI project, and provides rationale for further evaluation of the OASI-CB.

A retrospective study of the incidence and predisposing factors of third- and fourth-degree perineal tears

OBJECTIVES

To evaluate the rates of third- and fourth-degree tears and related predisposing factors for the tears in singleton vaginal deliveries. Methods: This was a retrospective study of third- and fourth-degree perineal tears in all women who underwent vaginal delivery in a tertiary hospital in Assir region between January 2014 and December 2019. There are approximately 5000 deliveries per year at the Abha Maternity and Children Hospital. The total number of deliveries during the study period was 31,788, of which 19,374 were delivered vaginally. Results: A total of 85 women (0.43% of all vaginal deliveries) had third-degree (n=81) or fourth-degree (n=4) perineal tears. The mean age of the women was 31 years (range: 16-46 years). Fifty-two of the 85 women (61%) were primiparous. Of the various obstetric parameters, episiotomy, occipitoposterior presentation, primigravida, multipara, and a previous episiotomy were found to be significant predisposing factors to third- and fourth-degree tears in our patients.

CONCLUSION

The low incidence of obstetric anal sphincter injuries in this study is likely the result of proactive manual protection of the perineum, valid indications for episiotomy, and attendance of senior staff members at all difficult deliveries.

Evaluation of Suzor forceps training by studying obstetric anal sphincter injuries: a retrospective study

BACKGROUND

Instrumental deliveries are an unavoidable part of obstetric practice. Dedicated training is needed for each instrument. To identify when a trainee resident can be entrusted with instrumental deliveries by Suzor forceps by studying obstetric anal sphincter injuries.

METHODS

A French retrospective observational study of obstetric anal sphincter injuries due to Suzor forceps deliveries performed by trainee residents was conducted from November 2008 to November 2016 at Limoges University Hospital. Perineal lesion risk factors were studied. Sequential use of a vacuum extractor and then forceps was also analyzed.

RESULTS

Twenty-one residents performed 1530 instrumental deliveries, which included 1164 (76.1%) using forceps and 89 (5.8%) with sequential use of a vacuum extractor and then forceps. Third and fourth degree perineal tears were diagnosed in 82 patients (6.5%). Residents caused fewer obstetric anal sphincter injuries after 23.82 (+/- 0.8) deliveries by forceps (p = 0.0041), or after 2.36 (+/- 0.7) semesters of obstetrical experience (p = 0.0007). No obese patient (body mass index> 30) presented obstetric anal sphincter injuries (p = 0.0013). There were significantly fewer obstetric anal sphincter injuries after performance of episiotomy (p <  0.0001), and more lesions in the case of the occipito-sacral position (p = 0.028). Analysis of sequential instrumentation did not find any additional associated risk.

CONCLUSION

Training in the use of Suzor forceps requires extended mentoring in order to reduce obstetric anal sphincter injuries. A stable level of competence was found after the execution of at least 24 forceps deliveries or after 3 semesters (18 months) of obstetrical experience.

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

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

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.

Delivery after an obstetric anal sphincter tear

Purpose

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

Methods

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

Results

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

Conclusion

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

Prediction of levator ani muscle avulsion by genital tears after vaginal birth-a prospective observational cohort study

INTRODUCTION

Visible birth tears and levator ani muscle (LAM) trauma are common after birth. For the diagnosis of LAM trauma ultrasound evaluation is advisable. As ultrasound equipment and trained personnel are not available everywhere at all times, we aimed to evaluate whether specific overt birth tears are an indicator for LAM trauma.

METHODS

In a prospective cohort study at our center from March 2017-April 2019, we evaluated vaginal births of nulliparous women with singletons in vertex presentation ≥ 36 + 0 gestational weeks for LAM trauma by translabial ultrasound and for overt birth tears by inspection. We then calculated the association of overt birth tears with complete LAM avulsion.

RESULTS

Of 213 women, 23.9% had any kind of LAM trauma, with 14.1% being complete avulsions. In univariate analysis, solely high-grade perineal tears (OASIS) were significantly associated with complete LAM avulsions.

CONCLUSIONS

Fourteen percent of women suffered a complete LAM avulsion after vaginal birth, with OASIS being the only associated parameter of significance. The occurrence of such trauma might be an indicator for a mismatch between the size of the fetus and the structures of the birth canal, leading to birth trauma. Assessing for LAM trauma by translabial ultrasound in women with OASIS might be worthwhile.

Mediolateral Episiotomy: Technique, Practice, and Training

Episiotomy is one of the most common obstetric procedures. However, restrictive use of episiotomy has led to a decrease in its use in the United States. Historically, mediolateral episiotomy has been performed less often than median episiotomy in the United States, but both have purported advantages and disadvantages. Emerging research on episiotomy and obstetric anal sphincter injuries has led to an examination of the effects of mediolateral episiotomy. This article describes performance of a mediolateral episiotomy in a situation of fetal bradycardia. Technical aspects of the incision and repair are described, and outcome data and knowledge gaps are summarized. Implications for practice, clinical competency, and education are reviewed.

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.

Passive management of labour may predispose to anal sphincter injury

INTRODUCTION AND HYPOTHESIS

To compare anal sphincter damage in two groups of primigravid women in Sydney: one passively managed in public hospitals, the other more actively managed in adjacent private hospitals. Data from actively managed labours at the National Women's Hospital, Dublin, served as an independent control.

METHODS

We carried out a comparative study of third and fourth degree anal sphincter tears in all primiparas delivering at term in the years 2010-2015 in six Sydney public teaching hospitals with data from patients delivered in six adjacent Sydney private hospitals. A second comparator was published data from the National Women's Hospital, Dublin, where active management is still performed under the direction of midwives. All data was publicly available from www.health.nsw.gov.au/hsnsw . The difference between the two groups: public hospitals were under MANDATORY (NSW DG's upper case emphasis) direction from the Director General of NSW Health (PD 2010-045 File no 09/638-3) for labour to proceed without any augmentation.

RESULTS

The study comprised 130,000 women. The mean third and fourth degree anal sphincter tear rate was 8.17% for the public hospitals and 1.52% for the private hospitals in the same period (p < 0.0003). Dublin's rate was 2.6%. There was no significant difference in the emergency Caesarean section rate 2010-2015 (13.7% private vs 12.7% public, 7.9% in National Women's Hospital Dublin) as well as an increase in epidurals, forceps/ventouse and lower Apgar scores.

CONCLUSION

Passive management of labour instituted in Sydney public hospitals by government directive seems to be associated with a higher rate of obstetric anal sphincter injuries than was observed with active management. In addition, there were more epidurals, forceps/ventouse, and lower Apgar scores. Our hypothesis of deflexion of the head causing deficient powers is logically appealing, but needs further proof.

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.

Reducing Perineal Lacerations Through Team-Based Simulation

INTRODUCTION

Vaginal deliveries that result in perineal trauma involve significant morbidity to women. Multiple strategies have been identified to reduce the risk of severe perineal lacerations. The objective of this study was to evaluate the effectiveness of an interprofessional simulation-based teams-training program aimed at reducing severe perineal lacerations during childbirth.

METHODS

A quasi-experimental pre-post single-group design was used to examine the performance of labor and delivery personnel at a large multihospital system after participating in a mixed-modality simulation program for reducing perineal lacerations. Multiple educational strategies aimed at management of second stage of labor (including laboring down, warm compresses, coaching, positioning, perineal support, controlled delivery of fetal head, and mediolateral episiotomy techniques) were taught using patients, task trainers, and a standardized curriculum during interprofessional educational sessions. Primary study outcomes were as follows: (a) pre-post differences in knowledge; (b) pre-post differences in team performance assessments; and (c) pre-post differences in safety culture. Secondary outcomes were severe perineal laceration rates.

RESULTS

During an 18-month period, 675 personnel in 4 hospitals participated in the program. Significant improvement was noted in pre-post scores of knowledge (59.86%, 93.87%, P < 0.0001), performance (36.54%, 93.45%, P < 0.0001), and safety culture (3.24, 1.45, 1 = high, 5 = low, P < 0.0001). Severe perineal laceration rates decreased by 33.38% since initiation. Rates fluctuated with the addition of new personnel and renewed educational programs.

CONCLUSIONS

A multimodal interprofessional simulation program of strategies to prevent severe perineal lacerations significantly improved knowledge, skills, and attitudes in labor and delivery personnel within a healthcare system. Severe perineal laceration rates were reduced.

Incidence of obstetric anal sphincter injuries after implementing the Triepi-45 tool to improve episiotomy angle in instrumental deliveries

OBJECTIVE

To assess the impact of Triepi-45-a tool that enables an episiotomy angle of 45° to be marked on the perineum at rest-on the incidence of obstetric anal sphincter injuries (OASIS) during operative vaginal delivery (OVD).

METHOD

A retrospective-prospective cohort study was performed among successive women who underwent OVD at Complejo Asistencial Universitario de de León, Spain, between 2011 and 2013 (preintervention cohort, n=986) and between 2014 and 2016 (intervention cohort, n=986) after implementation of an interventional programme in 2013 to improve the episiotomy angle, including use of Triepi-45, in OVD.

RESULTS

The intervention cohort had a lower incidence of OASIS than the preintervention cohort (70/986 [7.1%] vs 93/986 [9.4%]), but the difference was not significant, owing to the low use of Triepi-45 in the intervention cohort (n=375). However, the OASIS incidence was significantly lower in the Triepi-45 cohort than in the preintervention cohort (18/375 [4.8%] vs 93/986 [9.4%]; odds ratio, 0.47; 95% confidence interval, 0.26-0.86).

CONCLUSION

Use of Triepi-45 had a positive impact on reducing OASIS in OVD. It remains essential to raise obstetricians' awareness of the importance of the episiotomy angle and to implement the systematic use of tools to reduce the incidence of OASIS.

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.

Impact of animated instruction on tablets and hands-on training in applying bimanual perineal support on episiotomy rates: an intervention study

INTRODUCTION AND HYPOTHESIS

In Palestine, episiotomy is frequently used among primiparous women.This study assesses the effect of training birth attendants in applying bimanual perineal support during delivery by either animated instruction on tablets or hands-on training on episiotomy rates among primiparous women.

METHODS

An interventional cohort study was performed from 15 October 2015 to 31 January 2017, including all primiparous women with singletons and noninstrumental vaginal deliveries at six Palestinian hospitals. Intervention 1 (animated instructions on tablets) was conducted in Hospitals 1, 2, 3, and 4. Intervention 2 (bedside hands-on training) was applied in Hospitals 1 and 2 only. Hospitals 5 and 6 did not receive interventions. Differences in episiotomy rates in intervention and nonintervention hospitals were assessed before and after the interventions and presented as p values using chi-square test, and odds ratios (OR) with 95% confidence intervals (CI). Differences in the demographic and obstetric characteristics were presented as p values using the Kruskal-Wallis test.

RESULTS

Of 46,709 women, 12,841 were included. The overall episiotomy rate in the intervention hospitals did not change significantly after intervention 1, from 63.1 to 62.1% (OR = 0.96, 95% CI 0.84-1.08), but did so after intervention 2, from 61.1 to 38.1% (OR = 0.39, 95% CI 0.33-0.47). Rates after Intervention 2 changed from 65.0 to 47.3% (OR = 0.52, 95% CI 0.40-0.67) in Hospital 1 and from 39.4 to 25.1% (OR = 0.49, 95% CI 0.35-0.68) in Hospital 2.

CONCLUSIONS

Hands-on training of bimanual perineal support during delivery of primiparous women was significantly more effective in reducing episiotomy rates than animated instruction videos alone.

Severe perineal trauma among women undergoing vaginal birth after cesarean delivery: A population-based cohort study

BACKGROUND

To examine risk of severe perineal trauma among nulliparous women and those undergoing vaginal birth after cesarean delivery (VBAC).

METHODS

This is a population-based cohort study of all births to women with their two first consecutive singleton pregnancies in Stockholm-Gotland Sweden between 2008 and 2014. Risk of severe perineal trauma was compared between nulliparous women and those undergoing VBAC with severe perineal trauma being the main outcome measure. Associations between indication and timing of primary cesarean delivery and risk of severe perineal trauma in subsequent vaginal birth were analyzed using Poisson regression analysis.

RESULTS

The rate of severe perineal trauma among nulliparous women and those undergoing VBAC was 7.0% and 12.3%, respectively. Compared with nulliparous women, those undergoing VBAC were significantly older, had a shorter stature, and gave birth in a non-upright position to heavier infants with larger head circumferences. The rate of instrumental vaginal delivery among nulliparous women and those undergoing VBAC was 19.3% and 20.2%, respectively (P = 0.331). An increased risk of severe perineal trauma remained after adjustments among those undergoing VBAC (adjusted risk ratio 1.42, 95% CI 1.23-1.63). Level of risk was not associated with indication (dystocia or signs of fetal distress) of primary cesarean delivery, nor how far the woman had progressed in labor (fully dilated versus planned cesarean delivery) before delivering by cesarean.

CONCLUSIONS

Compared with nulliparous women, those undergoing VBAC are at increased risk of severe perineal trauma, irrespective of indication and timing of primary cesarean delivery.