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Randomized Controlled Trial
. 2024 Jun 17:385:e079014.
doi: 10.1136/bmj-2023-079014.

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

Sandra Bergendahl  1 , Maria Jonsson  2 , Susanne Hesselman  3 , Victoria Ankarcrona  4 , Åsa Leijonhufvud  5 , Anna-Carin Wihlbäck  6 , Tove Wallström  7 , Emmie Rydström  8 , Hanna Friberg  9 , Helena Kopp Kallner  4 , Sophia Brismar Wendel  4
Affiliations
Randomized Controlled Trial

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

Sandra Bergendahl et al. BMJ. .

Abstract

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.

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Conflict of interest statement

Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/disclosure-of-interest/ and declare: funding from the Swedish Research Council (2016-00526), the Stockholm Region (FoUI-960261/2021), and the Uppsala-Örebro Research Council (RFR-939428); no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.

Figures

Fig 1
Fig 1
Illustration of a standardised lateral episiotomy in the EVA trial
Fig 2
Fig 2
CONSORT flowchart of the modified intention-to-treat population
See this image and copyright information in PMC

References

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