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.

Pelvic floor dysfunction after intervention, compared with expectant management, in prolonged second stage of labour: A population-based questionnaire and cohort study.

OBJECTIVE: To investigate the effect of vacuum extraction (VE) or caesarean section (CS), compared with expectant management, on pelvic floor dysfunction (PFD) 1-2 years postpartum in primiparous women with a prolonged second stage of labour. DESIGN: A population-based questionnaire and cohort study. SETTING: Stockholm, Sweden. POPULATION: A cohort of 1302 primiparous women with a second stage duration of ≥3 h, delivering from December 2017 to November 2018. METHODS: The 1-year follow-up questionnaire from the Swedish National Perineal Laceration Register was distributed 12-24 months postpartum. Exposure was VE or CS at 3-4 h or 4-5 h, compared with expectant management. MAIN OUTCOME MEASURES: Pelvic floor dysfunction was defined as at least weekly symptoms of urinary incontinence, pelvic organ prolapse or a Wexner score of ≥4. The risk of PFD was calculated using Poisson regression with robust variance estimation, presented as crude and adjusted relative risks (RRs and aRRs) with 95% confidence intervals (95% CIs). The implication of obstetric anal sphincter injury (OASI) on pelvic floor disorders was investigated through mediation analysis. RESULTS: In total, 35.1% of women reported PFD. Compared with expectant management, the risk of PFD was increased after VE at 3-4 h (aRR 1.33, 95% CI 1.06-1.65) and 4-5 h (aRR 1.34, 95% CI 1.05-1.70), but remained unchanged after CS. The increased risk after VE was not mediated by OASI. CONCLUSIONS: Pelvic floor dysfunction was common in primiparous women after a prolonged second stage, and the risk of PFD increased after VE but was unaffected by CS, compared with expectant management. If a spontaneous vaginal delivery eventually occurred, allowing an extended duration of labour did not increase the risk of PFD.

Anal incontinence after a prolonged second stage of labor in primiparous women.

The objective was to investigate the effect of delivery mode on anal incontinence 1-2 years after delivery in primiparous women with prolonged second stage of labor. This population-based cohort and questionnaire study performed in Stockholm Region, Sweden, included 1302 primiparous women with a second stage ≥ 3 h from December 1st, 2017 through November 30th, 2018. Background characteristics and outcome data were retrieved from computerized records. Questionnaires based on Wexner score were distributed 1-2 years after delivery. Risk of anal incontinence, defined as Wexner score ≥ 2, was calculated using logistic regression and presented as crude and adjusted odds ratios (OR and aOR) with 95% confidence intervals (CI). Compared with cesarean section, vacuum extraction was associated with anal incontinence (aOR 2.25, 95% CI 1.21-4.18) while spontaneous delivery was not (aOR 1.55, 95% CI 0.85-2.84). Anal incontinence was independently associated with obstetric anal sphincter injuries (aOR 2.03, 95% CI 1.17-3.5) and 2nd degree perineal tears (aOR 1.36, 95% CI 1.03-1.81) compared with no or 1st degree perineal tear. Obstetric anal sphincter injury at vacuum extraction inferred the highest risk of anal incontinence (aOR 4.06, 95% CI 1.80-9.14), compared with cesarean section. Increasing duration of the prolonged second stage did not affect the risk.

Lateral episiotomy versus no episiotomy to reduce obstetric anal sphincter injury in vacuum-assisted delivery in nulliparous women: study protocol on a randomised controlled trial.

INTRODUCTION: Obstetric anal sphincter injury (OASIS) occurs in 5%-7% of normal deliveries and increases with vacuum extraction (VE) to 12%-14% in nulliparous women in Sweden. Lateral/mediolateral episiotomy may reduce the prevalence of OASIS at VE in nulliparous women. The current use of episiotomy is restrictive. The protective effect and consequences are uncertain. This trial will investigate if lateral episiotomy can reduce the prevalence of OASIS and assess short-term and long-term effects. METHODS AND ANALYSIS: This is a multicentre randomised controlled trial of lateral episiotomy versus no episiotomy in nulliparous women with a singleton, live fetus, after gestational week 34+0 with indication for VE. A lateral episiotomy of 4 cm is cut at crowning, 1-3 cm from the midline, at a 60° angle. The primary outcome is OASIS by clinical diagnosis analysed according to intention to treat. To demonstrate a 50% reduction in OASIS prevalence (from 12.4% to 6.2%), 710 women will be randomised at a 1:1 ratio. Secondary outcomes are pain, blood loss, other perineal injuries, perineal complications, Apgar score, cord pH and neonatal complications. Web-based questionnaires at baseline, 2 months, 1 and 5 years will be used to assess pain, incontinence, prolapse, sexual function, quality of life and childbirth experience. A subset of women will receive follow-up by pelvic floor sonography and pelvic examination. Mode of delivery and recurrence of OASIS/episiotomy in subsequent pregnancies will be assessed at 5 and 10 years using register data. ETHICS AND DISSEMINATION: The trial is open for enrolment. The trial has received ethical approval from the Regional Ethical Review Board of Stockholm and full funding from the Swedish Research Council. Women are interested in participation. The predominant restrictive view on episiotomy may limit recruitment. Results are of global interest and will be disseminated in peer-reviewed journals and at international congresses. TRIAL REGISTRATION NUMBER: NCT02643108; Pre-results.

Operator experience affects the risk of obstetric anal sphincter injury in vacuum extraction deliveries.

INTRODUCTION: Delivery by vacuum extraction is a major risk factor for obstetric anal sphincter injury. The aim of this study was to assess risk factors for obstetric anal sphincter injury in vacuum extraction in nulliparous women, specifically operator-related factors. A secondary aim was to assess other complications of vacuum extraction that are dependent on operator experience. MATERIAL AND METHODS: A historical cohort study of nulliparous women with a live single fetus ≥34 weeks, delivered by vacuum extraction at a teaching hospital in Sweden in 1 year (2013), using data from medical records. Risk of obstetric anal sphincter injury was assessed for obstetricians (reference), gynecologists, and residents, and adjusted for maternal, fetal, procedure-related, and operator-related covariates using unconditional logistic regression. Results are presented as prevalence and crude and adjusted odds ratio (aOR) with 95% CI. RESULTS: In total, 323 nulliparous women delivered by vacuum extraction were included. Obstetric anal sphincter injury occurred in 57 (17.6%) women. Fifteen (11.5%) obstetric anal sphincter injuries occurred in vacuum extractions performed by obstetricians, 10 (13.5%) by gynecologists (aOR 1.84, 95% CI 0.72-4.70), and 32 (26.9%) by residents (aOR 5.13, 95% CI 2.20-11.95). Maternal height ≤155 cm (aOR 4.63, 95% CI 1.35-15.9) and conversion to forceps (aOR 19.4, 95% CI 1.50-252) increased the risk of obstetric anal sphincter injury. Operator gender, night shift work, or being a frequent operator did not affect the risk of obstetric anal sphincter injury. Postpartum hemorrhage and fetal complications did not differ between operator categories. CONCLUSIONS: The adjusted risk of obstetric anal sphincter injury in nulliparous women was five times higher in vacuum extractions performed by residents compared with those performed by obstetricians. Vacuum extractions performed by gynecologists did not carry an increased risk of obstetric anal sphincter injury. Experience in years of training, rather than frequency of the procedure, seemed to have the highest impact on reducing obstetric anal sphincter injury in vacuum extractions, which indicates a need for increased training and supervision.