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][1]. The study protocol and the statistical analysis plan is available with publication as supplementary material. Deidentified individual participant data and a data dictionary defining each field in the set will be made available to others for meta-analysis with investigator support after approval of a proposal (sophia.brismar-wendel{at}regionstockholm.se) and with a signed data access agreement. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT02643108&atom=%2Fbmj%2F385%2Fbmj-2023-079014.atom

中文翻译：

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未产妇真空辅助分娩 (EVA) 中的会阴侧切术或不进行会阴切开术：多中心、开放标签、随机对照试验


目的 评估与不进行会阴切开术相比，会阴侧切术对需要负压吸引的未产妇产科肛门括约肌损伤的影响。设计一项多中心、开放标签、随机对照试验。设置瑞典八家医院，2017-23。参与者包括 717 名未产妇，其中有一个妊娠 34 周或以上的活胎儿，需要真空吸引术，被随机分配 (1:1) 进行会阴侧切术或使用密封不透明信封不进行会阴切开术。随机分组按研究地点分层。干预 在真空抽吸过程中，在胎儿头部加冕时，进行标准化的侧会阴切开术，从距后胎盘 1-3 厘米处开始，与中线成 60°（45-80°）角，距中线 4 厘米（3-80°）。 5厘米）长。除非认为是必要的，否则比较不是会阴切开术。主要结果指标 真空辅助分娩 (EVA) 试验中会阴切开术的主要结果是产科肛门括约肌损伤，通过联合目视检查和直肠指检和阴道检查进行临床诊断。主要分析使用了修改后的意向治疗人群，其中包括所有尝试或成功真空吸引术的同意女性。作为显着性水平 P<0.01 的中期分析结果，主要终点以 4% 显着性水平和伴随的 96% 置信区间 (CI) 进行测试。结果 2017年7月1日至2023年2月15日，717名女性被随机分配：354名（49%）接受会阴侧切术，363名（51%）不接受会阴切开术。在尝试真空吸引术之前，一名妇女撤回同意，14 名妇女自然分娩，剩下 702 名妇女用于初步分析。 在干预组中，344 名女性中有 21 名（6%）患有产科肛门括约肌损伤，而对照组 358 名女性中有 47 名（13%）患有产科肛门括约肌损伤（P=0.002）。风险差异为-7.0%（96% CI -11.7%至-2.5%）。根据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）。各组之间在产后疼痛、失血、新生儿结局或总体不良事件方面没有显着差异，但干预组的伤口感染和裂开更多。结论 对于需要负压吸引术的未产妇，可以推荐行会阴侧切术，以显着降低产科肛门括约肌损伤的风险。试验注册 ClinicalTrials.gov [NCT02643108][1]。研究方案和统计分析计划可作为补充材料出版。在提案 (sophia.brismar-wendel{at}regionstockholm.se) 获得批准后，将向其他人提供去识别化的个人参与者数据和定义集合中每个字段的数据字典，以便在研究者的支持下进行荟萃分析，并提供签名数据访问协议。 [1]：/lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT02643108&atom=%2Fbmj%2F385%2Fbmj-2023-079014。原子