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

Lateral episiotomy or no episiotomy in vacuum assisted delivery in nulliparous women (EVA): multicentre, open label, randomised controlled trial

OBJECTIVE

To assess the effect of lateral episiotomy, compared with no episiotomy, on obstetric anal sphincter injury in nulliparous women requiring vacuum extraction.

DESIGN

A multicentre, open label, randomised controlled trial.

SETTING

Eight hospitals in Sweden, 2017-23.

PARTICIPANTS

717 nulliparous women with a single live fetus of 34 gestational weeks or more, requiring vacuum extraction were randomly assigned (1:1) to lateral episiotomy or no episiotomy using sealed opaque envelopes. Randomisation was stratified by study site.

INTERVENTION

A standardised lateral episiotomy was performed during the vacuum extraction, at crowning of the fetal head, starting 1-3 cm from the posterior fourchette, at a 60° (45-80°) angle from the midline, and 4 cm (3-5 cm) long. The comparison was no episiotomy unless considered indispensable.

MAIN OUTCOME MEASURES

The primary outcome of the episiotomy in vacuum assisted delivery (EVA) trial was obstetric anal sphincter injury, clinically diagnosed by combined visual inspection and digital rectal and vaginal examination. The primary analysis used a modified intention-to-treat population that included all consenting women with attempted or successful vacuum extraction. As a result of an interim analysis at significance level P<0.01, the primary endpoint was tested at 4% significance level with accompanying 96% confidence interval (CI).

RESULTS

From 1 July 2017 to 15 February 2023, 717 women were randomly assigned: 354 (49%) to lateral episiotomy and 363 (51%) to no episiotomy. Before vacuum extraction attempt, one woman withdrew consent and 14 had a spontaneous birth, leaving 702 for the primary analysis. In the intervention group, 21 (6%) of 344 women sustained obstetric anal sphincter injury, compared with 47 (13%) of 358 women in the comparison group (P=0.002). The risk difference was -7.0% (96% CI -11.7% to -2.5%). The risk ratio adjusted for site was 0.47 (96% CI 0.23 to 0.97) and unadjusted risk ratio was 0.46 (0.28 to 0.78). No significant differences were noted between groups in postpartum pain, blood loss, neonatal outcomes, or total adverse events, but the intervention group had more wound infections and dehiscence.

CONCLUSIONS

Lateral episiotomy can be recommended for nulliparous women requiring vacuum extraction to significantly reduce the risk of obstetric anal sphincter injury.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02643108.

Evaluation of perineal wound healing and pain outcomes after low-angle mediolateral episiotomy in women undergoing vaginal childbirth: A systematic review and meta-analysis

The efficacy of episiotomy, particularly the angle of incision in mediolateral episiotomies, remains a significant area of inquiry in obstetrics. This meta-analysis aimed to evaluate the impact of low-angle mediolateral episiotomy on perineal wound healing and pain outcomes in women undergoing vaginal childbirth. Adhering to PRISMA guidelines, a systematic review was conducted using the PICO framework. Studies were selected based on predefined inclusion and exclusion criteria, focusing on randomised controlled trials (RCTs) involving low-angle mediolateral episiotomies. Comprehensive literature searches were performed across major electronic databases including PubMed, Embase, Web of Science and Cochrane Library. Data extraction and quality assessments were meticulously carried out by independent reviewers, employing the Cochrane Collaboration's risk of bias tool. A total of 1246 articles were initially identified, with 8 articles meeting the strict inclusion criteria for the final analysis. The meta-analysis revealed significant heterogeneity among studies regarding postoperative pain (p < 0.0001, I2 = 77.5%), and employed a random-effects model. Results showed that low-angle episiotomies significantly reduced postoperative pain (OR = 0.27, 95% CI: 0.17-0.42, p < 0.001), and increased first-degree healing rates (OR = 2.95, 95% CI: 2.20-3.96, p < 0.001) compared to traditional angles. Sensitivity analyses confirmed the stability of these findings, and no significant publication bias was detected. The analysis suggests that low-angle episiotomies can potentially reduce postoperative perineal pain and enhance wound healing. However, the limited number and varying quality of the included studies warrant cautious interpretation of these results. Further well-designed studies are needed to corroborate these findings and guide clinical practice.

Obstetric Interventions Among Native and Migrant Women: The (Over)use of Episiotomy in Portugal

Objective: Episiotomy, defined as the incision of the perineum to enlarge the vaginal opening during childbirth, is one of the most commonly performed surgical interventions in the world. We aimed to determine if migrant status is associated with episiotomy, and if individual characteristics mediate this association. Methods: We analyzed data from the Bambino study, a national, prospective cohort of migrant and native women giving birth at a public hospital in mainland Portugal between 2017 and 2019. We included all women with vaginal delivery. The association between migrant status and episiotomy was assessed using multivariable multilevel random-effect logistic regression models. We used path analysis to quantify the direct, indirect and total effects of migrant status on episiotomy. Results: Among 3,583 women with spontaneous delivery, migrant parturients had decreased odds of episiotomy, especially those born in Africa, compared to native Portuguese women. Conversely, with instrumental delivery, migrant women had higher odds of episiotomy. Disparities in episiotomy were largely explained by maternity units' factors, and little by maternal and fetal characteristics. Conclusion: Our results suggest non-medically justified differential episiotomy use during childbirth and highlight the importance of developing evidence-based recommendations for episiotomy use in a country with a high frequency of medical interventions during delivery.

Does transperineal ultrasound predict the risk of perineal trauma in women with term pregnancy? A prospective observational study

PURPOSE

This study was conducted to evaluate the prevalence of perineal trauma during childbirth and to assess the correlations of the pelvic floor dimensions and fetal head station with obstetric trauma in a prospectively recruited cohort of women.

METHODS

The study included women with a gestational age of at least 37 weeks, who were carrying a single fetus in a cephalic presentation. Transperineal ultrasound (TPU) was performed prior to the onset of labor or labor induction. The purpose was to measure the anteroposterior diameter (APD) of the levator ani muscle (LAM) and the angle of progression, at both rest and maximum Valsalva maneuver. The head-perineum distance was assessed only at rest.

RESULTS

A total of 296 women were included. Of the 253 women who delivered vaginally, 19% (48/253) experienced no perineal trauma, 18.2% (46/253) received an episiotomy during childbirth, 34.4% (87/253) sustained a first-degree laceration, 25.3% (64/253) had a second-degree laceration, and 3.2% had a third- or fourth-degree laceration (8/253). Women with episiotomy had a significantly shorter median APD under Valsalva than women without perineal trauma. Furthermore, women with LAM coactivation (identified by a negative difference between the APD at Valsalva and the APD at rest) were approximately three times more likely to undergo an operative vaginal delivery and over five times more likely to sustain a third- or fourth-degree tear during childbirth than women who exhibited normal relaxation of the LAM during the Valsalva maneuver.

CONCLUSION

TPU may predict the risk of perineal trauma in women with term pregnancy during childbirth.

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.

Effectiveness of small-angle episiotomy on incisional laceration rate, suturing time, and incisional bleeding in primigravida: A meta-analysis

Objective

To investigate the effect of small-angle lateral perineal incision on postoperative perineal rehabilitation in primiparous women.

Method

The Cochrane Library, PubMed, Embase, CINAHL, CNKI, WanFang, VIP, and the Chinese Biomedical Literature Database were searched for randomized controlled trials (RCTs) on the effect of small-angle episiotomy on postoperative maternal perineal wound rehabilitation in puerpera until April 3, 2022. Two researchers independently performed literature screening, data extraction and evaluation of risk of bias in the included literature, and statistical analysis of the data was performed using RevMan 5.4 and Stata 12.0 software.

Result

A total of 25 RCTs were included, with a total sample of 6,366 cases. Meta-analysis results showed that the use of small-angle episiotomy reduced incisional tearing [OR = 0.32, 95% CI (0.26, 0.39)], shortened incisional suture time [MD = −4.58 min, 95% CI (−6.02, −3.14)] and reduced incisional bleeding [MD = −19.08 mL, 95% CI (−19.53, −18.63)], with statistically significant differences (all p &lt; 0.05). There was no significant difference in the rate of severe laceration between the two groups [OR = 2.32, 95% CI (0.70, 7.70), p &gt; 0.05].

Conclusion

The use of a small-angle episiotomy during vaginal delivery can reduce the incision tear rate without increasing the incidence of severe perineal laceration, while shortening the incisional suturing time and reducing incisional bleeding. It can be used clinically according to birth canal conditions of the maternal, the intrauterine condition of the fetus and maternal needs.

Systematic Review Registration

PROSPERO International Prospective Register of Systematic Reviews [CRD42022369698]; [https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=369698].

Effectiveness of episiotomy to prevent OASIS in nulliparous women at term

OBJECTIVE

To assess the association between episiotomy and severe obstetric anal sphincter injury (OASIS) in nulliparous women at term according to the use of an instrument for delivery with control confounding by indication.

METHODS

This was an observational retrospective cohort study including 12 346 women from 2004 to 2020. All nulliparous women with a cephalic singleton pregnancy were included. The primary outcome was the occurrence of OASIS. Association between episiotomy and OASIS was assessed by multivariate logistic regression with adjustment for confounding factors and stratification on the use of an instrument at delivery. Propensity score matching was used to account for indication bias.

RESULTS

Among 12 346 women included, 7803 (63.2%) had an episiotomy and 4543 (36.8%) did not have an episiotomy; the rate of OASIS was similar in both groups (0.7%). After stratification on use of instrument, an association between episiotomy and OASIS was shown in the case of instrumental delivery (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.26-0.80) but not if the delivery was spontaneous (OR 0.76, 95% CI 0.29-1.98). The result was similar after matching on propensity score (in the case of operative vaginal delivery: OR 0.20, 95% CI 0.10-0.75).

CONCLUSION

Episiotomy seems to be a protective factor for OASIS in nulliparous woman at term only in the case of operative vaginal delivery.

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.