Episiotomy use among vaginal deliveries and the association with anal sphincter injury: a population-based retrospective cohort study

Variation in Episiotomy Use Among Nulliparous Individuals by Maternity Care Provider and Associated Rates of Obstetric Anal Sphincter Injury

OBJECTIVES

To quantify variation in the association between episiotomy and obstetric anal sphincter injury (OASI) by maternity care provider in spontaneous and operative vaginal deliveries (SVDs and OVDs).

METHODS

Population-based retrospective cohort study of vaginal, term deliveries among nullipara in Canada (2004-2015). Adjusted rate ratios (ARRs) and 95% CIs were estimated using log-binomial regression to quantify the associations between episiotomy and OASI, stratified by care provider (obstetrician [OB], family physician [FP], or registered midwife [RM]) while adjusting for potential confounders.

RESULTS

The study included 631 642 deliveries. Episiotomy use varied by provider: among SVDs, the episiotomy rate was 19.6%, 14.4%, and 8.4% in the OB, FP, and RM groups, respectively. The rate of OASI was higher among SVDs with versus without episiotomy (5.8% vs 4.6%). Conversely, OASI occurred less frequently in operative vaginal deliveries with episiotomy (15.3%) compared with those without (16.7%). In all provider groups, the ARR for OASI was increased with episiotomy in SVD and decreased with episiotomy with forceps delivery. No differences in these associations were observed by provider except among vacuum delivery (ARR with episiotomy vs. without, OB: 0.88, 95% CI 0.84-0.92; FP: 0.89, 95% CI 0.83-0.96, RM: 1.22, 95% CI 1.02-1.48).

CONCLUSIONS

In nullipara, irrespective of maternity care provider, there is a positive association between episiotomy and OASI among SVDs and an inverse association between episiotomy and deliveries with forceps. The relationship between episiotomy and OASI is modified by maternity care providers among vacuum deliveries.

Implementation of Episcissors-60 for Prevention of Obstetric Anal Sphincter Injuries (OASIS) in a Centre with Low Episiotomy Rates

OBJECTIVE

The purpose of this study was to determine whether introduction of Episcissors-60 into a labour and birth unit would decrease the incidence of Obstetric Anal Sphincter Injuries (OASIS).

METHODS

A before-and-after quality improvement study was conducted between April 1, 2020 and March 31, 2021. All patients who had a vaginal delivery were included in this study. All healthcare providers who perform vaginal deliveries were offered an educational session. Episcissors-60 were then introduced into a labour and birth unit. The primary outcome measure was the change in incidence of OASIS before and after introduction of Episcissors-60. Secondary outcome measures were episiotomy rates before and after introduction of Episcissors-60, device-related adverse events, and provider satisfaction and feedback. Data was analyzed using chi-square tests, independent t-tests, and Mann-Whitney tests.

RESULTS

A total of 1383 vaginal deliveries occurred prior and 1254 vaginal deliveries after introduction of Episcissors-60. There was a decrease in the total OASIS rate from 7.37% of all vaginal deliveries prior to 5.37% after introduction of Episcissors-60 (P = .037). The episiotomy rate was 11.42% prior to and 9.97% after introduction of Episcissors-60 (P = .228). OASIS rate in women who had an episiotomy was 12.02% before and 13.60% after introduction of Episcissors-60 (P = .421).

CONCLUSION

Although introduction of Episcissors-60 was associated with a statistically significant decrease in total OASIS rate, there was no difference in OASIS rates within the subgroup that received an episiotomy. Therefore, reduction in the total OASIS rate in this study cannot be attributed to the use of Episcissors-60.

Episiotomy for Medical Indications during Vaginal Birth-Retrospective Analysis of Risk Factors Determining the Performance of This Procedure

The WHO (World Health Organization) recommends that the percentage of perineal incisions should not exceed 10%, indicating that this is a good goal to achieve, despite the fact that it is still a frequently used medical intervention in Poland. The risk factors for perineal incision that have been analyzed so far in the literature allow, among others, to limit the frequency of performing this procedure. Are they still valid? Have there been new risk factors that we should take into account? We have conducted this study to find the risk factors for performing perineal incision that would reduce the frequency of this procedure. The aim of the study was to check whether the risk factors that were analyzed in the literature are still valid, to find new risk factors for perineal incisions and to compare them among Polish women. This was a single-center retrospective case-control study. The electronic patient records of Saint Sophia's Hospital in Warsaw, Poland, a tertiary hospital was used to create an anonymous retrospective database of all deliveries from 2015 to 2020. The study included the analysis of two groups, the study group of patients who had had an episiotomy, and the control group-patients without an episiotomy in cases where an episiotomy was indicated. A logistic regression model was developed to assess the risk factors for perineal laceration. Independent risk factors for episiotomy in labor include oxytocin use in the second stage of labor (OR (Odds Ratio) = 6.00; 95% CI (Confidence Interval): 4.76-7.58), the supply of oxytocin in the first and the second stage of labor (OR = 3.18; 95% CI: 2.90-3.49), oxytocin use in the first stage of labor (OR = 2.72; 95% CI: 2.52-3.51), state after cesarean section (OR = 2.97; 95% CI: 2.52-3.51), epidural anesthesia use (OR = 1.77; 95% CI: 1.62-1.93), male gender (OR = 1.10; 95% CI: 1.02-1.19), and prolonged second stage of labor (OR = 1.01; 95% CI: 1.01-1.01). A protective factor against the use of an episiotomy was delivery in the Birth Centre (OR = 0.43; 95% CI: 0.37-0.51) and mulitpara (OR = 0.31; 95% CI: 0.27-0.35). To reduce the frequency of an episiotomy, it is necessary consider the risk factors of performing this procedure in everyday practice, e.g., limiting the use of oxytocin or promoting alternative places of delivery.

Increased risk of obstetric anal sphincter injury in women undergoing vaginal delivery after caesarean section: A systematic review and meta-analysis

BACKGROUND

There is increased focus on obstetric anal sphincter injury (OASI) and there are several well-established risk factors such as birthweight, instrumental delivery and median episiotomy. Some studies have found increased risk of OASI in women delivering vaginally after a previous caesarean section (VBAC).

OBJECTIVE

To evaluate whether there is increased prevalence of OASI in VBAC compared with primiparous women.

SEARCH STRATEGY

Literature search using PubMed, Embase and Cochrane databases.

SELECTION CRITERIA

All studies with data on both primiparous women and women undergoing VBAC were included. All included studies were evaluated using the "SIGN - methodology checklist" to verify if the quality was acceptable.

DATA COLLECTION AND ANALYSIS

This systematic review included 23 articles conducted in 11 countries over 19 years. Included studies were analysed using RevMan version 5.4.

MAIN RESULTS

We found increased prevalence of OASI in the VBAC group; 8.18% (95% confidence interval [CI] 8.07-8.29) compared with 6.59% (95% CI 6.56-6.62) in primiparous women. Correspondingly, the meta-analysis revealed increased prevalence for OASI in the VBAC group (odds ratio 1.27, 95% CI 1.10-1.47). We found a high level of heterogeneity (I²  = 98%).

CONCLUSION

Women undergoing VBAC had a higher prevalence of OASI compared with primiparous women.

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.

Maternal and neonatal trauma following operative vaginal delivery

Background:

Operative vaginal delivery (OVD) is considered safe if carried out by trained personnel. However, opportunities for training in OVD have declined and, given these shifts in practice, the safety of OVD is unknown. We estimated incidence rates of trauma following OVD in Canada, and quantified variation in trauma rates by instrument, region, level of obstetric care and institutional OVD volume.

Methods:

We conducted a cohort study of all singleton, term deliveries in Canada between April 2013 and March 2019, excluding Quebec. Our main outcome measures were maternal trauma (e.g., obstetric anal sphincter injury, high vaginal lacerations) and neonatal trauma (e.g., subgaleal hemorrhage, brachial plexus injury). We calculated adjusted and stabilized rates of trauma using mixed-effects logistic regression.

Results:

Of 1 326 191 deliveries, 38 500 (2.9%) were attempted forceps deliveries and 110 987 (8.4%) were attempted vacuum deliveries. The maternal trauma rate following forceps delivery was 25.3% (95% confidence interval [CI] 24.8%–25.7%) and the neonatal trauma rate was 9.6 (95% CI 8.6–10.6) per 1000 live births. Maternal and neonatal trauma rates following vacuum delivery were 13.2% (95% CI 13.0%–13.4%) and 9.6 (95% CI 9.0–10.2) per 1000 live births, respectively. Maternal trauma rates remained higher with forceps than with vacuum after adjustment for confounders (adjusted rate ratio 1.70, 95% CI 1.65–1.75) and varied by region, but not by level of obstetric care.

Interpretation:

In Canada, rates of trauma following OVD are higher than previously reported, irrespective of region, level of obstetric care and volume of OVD among hospitals. These results support a reassessment of OVD safety in Canada.

European guidelines on perinatal care- Peripartum care Episiotomy

OF RECOMMENDATIONS1. Episiotomy should be performed by indication only, and not routinely (Moderate quality evidence +++-; Strong recommendation). Accepted indications for episiotomy are to shorten the second stage of labor when there is suspected fetal hypoxia (Low quality evidence ++-; Weak recommendation); to prevent obstetric anal sphincter injury in vaginal operative deliveries, or when obstetric sphincter injury occurred in previous deliveries (Moderate quality evidence +++-; Strong recommendation)2. Mediolateral or lateral episiotomy technique should be used (Moderate quality evidence +++-; Strong recommendation). Labor ward staff should be offered regular training in correct episiotomy techniques (Moderate quality evidence +++-; Strong recommendation).3. Pain relief needs to be considered before episiotomy is performed, and epidural analgesia may be insufficient. The perineal skin needs to be tested for pain before an episiotomy is performed, even when an epidural is in place. Local anesthetics or pudendal block need to be considered as isolated or additional pain relief methods (Low quality evidence ++-; Strong recommendation).4. After childbirth the perineum should be carefully inspected, and the anal sphincter palpated to identify possible injury (Moderate quality evidence +++-; Strong recommendation). Primary suturing immediately after childbirth should be offered and a continuous suturing technique should be used when repairing an uncomplicated episiotomy (High quality evidence ++++; Strong recommendation).

Perspectives of skilled birth attendants and pregnant women regarding episiotomy: a quantitative approach

Background

The World Health Organization recommended less than 10% episiotomy rate for Skilled Birth Attendants (SBAs) and hospitals in 1996. More than two decades afterwards, some health facilities are still grappling with meeting the set target.

Objectives

This study assessed the perspectives of SBAs and pregnant women regarding episiotomy in a Nigerian university teaching hospital.

Methods

A cross-sectional design was employed. Census sampling was used to select 19 SBAS and 973 vaginal birth records from 2019, while consecutive sampling technique was used to enrol 134 consenting pregnant women obtaining antenatal services in the facility. Data was collected using a three part instrument involving a data extraction sheet, episiotomy practice questionnaire for SBAs, and feelings about episiotomy questionnaire for pregnant women. Assembled data were summarised with descriptive statistics.

Results

The episiotomy rate was 345(35.5%). About 266 (77.1%) of first time mothers (primips) and 79(22.9%) of nonfirst time mothers (multips) received episiotomy. Ten (52.6%) of the SBAs were unsure of any evidence supporting routine episiotomy. All the 19(100%) SBAs reported that there was no existing facility-based policy regarding routine episiotomy. Seventy five (56%) of the pregnant women reported feeling generally bad about episiotomy. One hundred and one (82.3%) of them hinted that they will not feel satisfied if they were given episiotomy with the reason that it ensures quick vaginal birth.

Conclusion

The rate of episiotomy was higher than global recommended standards and primips are disproportionately affected. If organised by professional societies, more scientific conferences on limiting episiotomy might remedy this situation.

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.

Health care workers' perceptions of episiotomy in the era of respectful maternity care: a qualitative study of an obstetric training program in Mexico

BACKGROUND

Episiotomy in Mexico is highly prevalent and often routine - performed in up to 95% of births to primiparous women. The WHO suggests that episiotomy be used in selective cases, with an expected prevalence of 15%. Training programs to date have been unsuccessful in changing this practice. This research aims to understand how and why this practice persists despite shifts in knowledge and attitudes facilitated by the implementation of an obstetric training program.

METHODS

This is a descriptive and interpretative qualitative study. We conducted 53 pre and post-intervention (PRONTO© Program) semi-structured interviews with general physician, gynecologists and nurses (N = 32, 56% women). Thematic analysis was carried out using Atlas-ti© software to iteratively organize codes. Through interpretive triangulation, the team found theoretical saturation and explanatory depth on key analytical categories.

RESULTS

Themes fell into five major themes surrounding their perceptions of episiotomy: as a preventive measure, as a procedure that resolves problems in the moment, as a practice that gives the clinician control, as a risky practice, and the role of social norms in practicing it. Results show contradictory discourses among professionals. Despite the growing support for the selective use of episiotomy, it remains positively perceived as an effective prophylaxis for the complications of childbirth while maintaining control in the hands of health care providers.

CONCLUSIONS

Perceptions of episiotomy shed light on how and why routine episiotomy persists, and provides insight into the multi-faceted approaches that will be required to affect this harmful obstetrical practice.

Pelvic floor dysfunction in primiparous women up to 6 months after delivery: cohort study

OBJECTIVE

To analyze pelvic floor muscular strength (PFMS), urinary (UI) and anal (AI) incontinence and dyspareunia in primiparous women up to 6 months after normal or cesarean delivery.

METHODS

this is a prospective cohort with 169 women (128 normal births, 41 cesarean sections), followed between 50-70 and 170-190 days postpartum, when PFMS was measured using perineometry, and UI and AI and dyspareunia, through interview.

RESULTS

PFMS, UI and dyspareunia were similar between types of delivery. The difference was significant only for the time elapsed, with improvement in the studied period (2 and 6 months postpartum). Regarding AI, there was a significant difference between 2 and 6 months postpartum, with an interaction between type of delivery and time (p=0.022).

CONCLUSION

the type of delivery did not show any influence on pelvic floor dysfunctions, except for AI. For all outcomes, there was an improvement in the period studied.

Obstetric anal sphincter injury following previous vaginal delivery

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injury (OASI) is a debilitating complication of vaginal delivery. The aim of this study was to identify risk factors for OASI in women with a previous vaginal delivery. We further attempted to detect specific risk factors for severe OASI in this subgroup.

METHODS

We conducted a retrospective cohort study between 2003 and 2019. The study group included women who had a singleton, live, vertex, vaginal delivery at term and who also had at least one previous vaginal delivery. The control group included women with at least one previous vaginal delivery without OASI. General medical history, obstetric history, and ante-, intra- and post-partum data were collected and compared between groups.

RESULTS

Following implementation of the inclusion criteria, 79,176 women were included. Allocation to study groups was according to OASI occurrence: 135 patients (0.2%) had a third- or fourth-degree perineal tear, while 79,041 patients (99.8%) had no such injury. Multivariate analysis revealed that one previous vaginal delivery, birthweight ≥ 3900 g (90th percentile), vacuum-assisted vaginal delivery and episiotomy were associated with increased risk of OASI. Comparison of more severe OASI (3C and 4th-degree) cases to the control group showed similar results with the addition of prolonged second stage and younger age to risk factors associated with severe OASI while episiotomy was no longer significant.

CONCLUSION

In women with a previous vaginal delivery, one vs. two or more previous vaginal deliveries, increased birthweight, vacuum-assisted vaginal delivery and episiotomy are risk factors for OASI.

Knowledge, attitude and experience of episiotomy practice among obstetricians and midwives: a cross-sectional study from China

OBJECTIVE

Episiotomy is still performed widely by obstetricians and midwives in some Chinese maternity units, but the reasons are unknown. This study aims to determine the knowledge, attitude and experience towards the practice of episiotomy among obstetricians and midwives in China's public hospitals and consider strategies to reduce its practice.

METHODS

A cross-sectional web survey using a self-administered questionnaire was conducted among obstetricians and midwives in 90 public hospitals in Henan Province, China.

RESULTS

900 (82.21%) participants completed the questionnaire. Average knowledge level (4.15, SD=1.10) on complications and overuse was identified among participants. Episiotomy was performed more frequently in secondary hospitals than in tertiary hospitals (p<0.05). Senior clinicians were more likely to perform episiotomy than younger ones (p<0.05). Almost half of the clinicians (42.11%) considered the current rate of episiotomy (45%) to be right or too low. The most common reason for performing episiotomy identified by obstetricians (83.94%) and midwives (79.69%) was to reduce third-degree or fourth-degree perineal laceration. Both obstetricians (80.29%) and midwives (82.57%) agreed that the most significant obstacle to reducing the rate of episiotomy was lack of training on reducing perineal tears.

CONCLUSION

In sum, episiotomy was driven by previous training, practitioners' experience and local norms rather than the latest medical evidence. Clinicians in secondary hospitals and senior clinicians are key training targets. It is urgent to improve current clinical policies and surgical procedure guidelines for obstetricians and midwives regarding episiotomy.

Dispareunia en mujeres después de parto vaginal. Prevalencia en dos clínicas de Armenia, Colombia, 2012-2017

Se realizó un estudio de corte transversal que tuvo como objetivo determinar la prevalencia de la dispareunia en mujeres con parto vaginal, evaluar posibles factores de riesgo y la asociación con la episiotomía. Ingresaron mujeres atendidas por parto vaginal entre 2012 y 2017 en dos clínicas de alta complejidad en Armenia (Colombia). Se utilizó el cuestionario Índice de Función Sexual Femenina (IFFS-6) para evaluar la función sexual. Los resultados reportan una prevalencia de dispareunia del 59,37%, siendo más prevalente en mujeres sometidas a episiotomía (OR: 68,17; IC95 %: 60,57-79,15). Respecto a la asociación de la episiotomía con la presencia de dispareunia se encontró asociación significativa con la episiotomía medio-lateral (OR: 8,17; IC95%: 2,15-56,32), lesión del esfínter (OR: 7,32; IC95%: 4,86-12,75) y dehiscencia de la sutura (OR: 6,48; IC95%: 4,92-14,28). Se observaron como factores de riesgo: antecedente de endometriosis (OR: 11,6; IC95 %: 9,15-17,52), dolor pélvico crónico (OR: 3,56; IC95%: 2,21–6,32) e ITS (OR: 2,67; IC95%: 1,54–5,14), p=0,003). Se concluye que la prevalencia de dispareunia en mujeres con parto vaginal, atendidas en Armenia, varía en función de la realización de episiotomía, asociándose tanto a las complicaciones de esta como a otros antecedentes.

Comparison of maternal and neonatal outcomes after forceps or spatulas-assisted delivery

OBJECTIVE

The aim of this study was to compare the perinatal outcomes associated with spatulas or forceps assisted delivery.

STUDY DESIGN

This is a bicentric retrospective cohort study including all assisted deliveries in cephalic presentation after 37 weeks of gestation, performed on singleton pregnancy with forceps and with spatulas in two tertiary centers. The main outcome was the rate of episiotomy. Secondary outcomes included obstetric anal sphincter injuries (OASIS), maternal outcomes and neonatal parameters.

RESULTS

Out of 37 002 deliveries, the overall rate of assisted delivery was 11.4 %, and 1 041 (2.8 %) assisted deliveries with forceps and 2 462 (6.7 %) spatulas deliveries were included. The rate of episiotomy was 90.3 % after forceps-assisted delivery and 70.9 % for spatulas (p < 0.001). The rate of OASIS was 7.2 % and 5.6 % respectively (p = 0.06). A slight but significant decrease in neonatal trauma after spatulas was observed.

CONCLUSION

In this retrospective cohort study, the episiotomy rate was higher with forceps assisted deliveries than with spatulas. Both instruments have low neonatal morbidity and are similar regarding OASIS.

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Risk factors for obstetric anal sphincter injury among parous women

PURPOSE

Nulliparity and operative vaginal delivery are established risk factor for obstetric anal sphincter injury (OASI). However, risk factors for OASIS occurrence among parous women delivering vaginally are not well-established. We aimed to study the risk factors for OASI occurrence among parous women.

METHODS

A retrospective study including all parous women who delivered vaginally at term during 2011-2019 at a university hospital. Deliveries of parous women with OASI were compared to deliveries without OASI. The risk factors associated with OASI were investigated.

RESULTS

Overall, 35,397 women were included in the study with an OASI rate of 0.4% (n = 144). A higher rate of only one previous vaginal delivery was noted in the OASI group (78.5% vs. 46.4%, OR [95% CI] 4.20, 2.82-6.25, p < 0.001). The rate of vacuum-assisted deliveries was comparable between the study groups. The median birth weight was higher among the OASI group (3566 vs. 3300 g, p < 0.001), as was the rate of macrosomic neonates (19.4% vs. 5.5%, OR [95% CI] 4.15, 2.74-6.29, p < 0.001). On multivariate logistic regression analysis, only two factors were independently positively associated with the occurrence of OASI: a history of only one previous vaginal delivery (adjusted OR [95% CI] 4.34, 2.90-6.49, p = 0.001), and neonatal birth-weight (for each 500 g increment) (adjusted OR [95% CI] 2.51, 1.84-3.44, p < 0.001).

CONCLUSIONS

Among parous women, the only factors found to be independently positively associated with OASI were the order of parity and neonatal birth-weight. Vacuum-assisted delivery was not associated with an increased risk of OASI among parous women.

Risk factors associated with severe perineal tears: A five-year study

OBJECTIVE

Our aim was to describe risk factors associated with 34DPT in operative and non-operative vaginal deliveries, over a five-year period.

STUDY DESIGN

This was a retrospective cohort study including 39,227 vaginal deliveries from 2013 to 2017 in a single French University Hospital. Annual characteristics of the analyzed population were recorded. Univariate logistic regression was used to evaluate the association between these characteristics and 34DPT. Multivariate analysis was used to identify combinations of risk factors associated with instrumental delivery.

RESULTS

The rate of perineal tears was constantly rising but rate of 34DPT was stable, ranging between 0.8 and 1.4% over the study period. Cesarean section rate was stable between 18.8% and 19.6%. Rate of diabetes, preeclampsia and obesity (BMI < 40) was increasing and episiotomy rate decreasing (from 19.8% to 11.8%). Operative deliveries rate remained stable between 11 and 12.8%. Multivariate regression showed that gestational age over 39 weeks (aOR 1.18, 95% CI [1.02; 1.35]), birth weight over 3500 g (aOR 1.62, 95% CI [1.05; 2.49]) were associated with 34DPT in patients without operative vaginal deliveries but not episiotomy. Gestational age (aOR 1.71, 95% CI [1.18; 2.47]), episiotomy (aOR 0.55, 95% CI [0.38; 0.79]) and diabetes (aOR 1.73, 95% CI [1.15; 2.61]) were associated with 34DPT among patients with operative vaginal deliveries.

CONCLUSION

In a tertiary medical center model with low cesarean section rate, factors associated with 34DPT were different among patients with or without operative vaginal delivery. The question of the protective effect of mediolateral episiotomy against 34DPT in case of operative delivery deserves further investigations.