Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
BMJ. 2024 Jun 17;385:e079014. doi: 10.1136/bmj-2023-079014.
To assess the effect of lateral episiotomy, compared with no episiotomy, on obstetric anal sphincter injury in nulliparous women requiring vacuum extraction.
A multicentre, open label, randomised controlled trial.
Eight hospitals in Sweden, 2017-23.
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.
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.
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).
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.
Lateral episiotomy can be recommended for nulliparous women requiring vacuum extraction to significantly reduce the risk of obstetric anal sphincter injury.
ClinicalTrials.gov NCT02643108.
评估在需要真空吸引的初产妇中，与不施行会阴切开术相比，施行外侧会阴切开术对产科肛门括约肌损伤的影响。
多中心、开放标签、随机对照试验。
瑞典 8 家医院，2017-2023 年。
717 名初产妇，单胎活胎 34 孕周或以上，需要真空吸引，使用密封不透明信封进行 1:1 随机分配至外侧会阴切开术或不施行会阴切开术。随机化按研究地点分层。
在胎儿头冠部施行标准的外侧会阴切开术，起始位置距离后联合 1-3cm，角度为 60°（45-80°），长度为 4cm（3-5cm）。除非认为是必需的，否则不作比较。
真空辅助分娩（EVA）试验的主要结局是产科肛门括约肌损伤，通过联合视诊、直肠和阴道指检进行临床诊断。主要分析采用改良意向治疗人群，包括所有尝试或成功施行真空吸引的同意参与者。由于中间分析达到显著性水平 P<0.01，主要终点以 4%的显著性水平进行测试，同时伴有 96%的置信区间（CI）。
2017 年 7 月 1 日至 2023 年 2 月 15 日，717 名妇女被随机分配：354 名（49%）施行外侧会阴切开术，363 名（51%）不施行会阴切开术。在尝试施行真空吸引前，1 名妇女撤回同意，14 名妇女自然分娩，702 名妇女纳入主要分析。在干预组，344 名妇女中有 21 名（6%）发生产科肛门括约肌损伤，而在对照组，358 名妇女中有 47 名（13%）发生（P=0.002）。风险差异为-7.0%（96%CI -11.7%至-2.5%）。基于地点调整的风险比为 0.47（96%CI 0.23 至 0.97），未调整的风险比为 0.46（0.28 至 0.78）。两组在产后疼痛、失血、新生儿结局或总不良事件方面无显著差异，但干预组的伤口感染和裂开发生率更高。
对于需要真空吸引的初产妇，施行外侧会阴切开术可显著降低产科肛门括约肌损伤的风险，值得推荐。
ClinicalTrials.gov NCT02643108。
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