Dear editor, I read with interest the systematic review with metanalysis written by Pereira et al. [1]. The role of episiotomy has become a highly debated and clinically relevant topic in the last decade. It is well demonstrated that, except for operative vaginal delivery, a systematic policy of episiotomy is not associated with relevant advantages compared with a selective policy. However, it is not correct to state that episiotomy could be a foe of female quality of life in every case, because this sentence is not evidence based [2, 3]. The merit of Pereira and co-authors was to try to clarify the current evidence on the comparison between a nonversus a selective episiotomy policy. Unfortunately, the authors included only two randomized articles [4, 5], and this is the first relevant limitation. However, the strongest bias of the paper is that the authors compared two totally identical groups. Indeed, the study by SagiDain reported an episiotomy rate of 26.5% and 21.4% (p = 0.35) in the selective versus non-episiotomy group, respectively [4]. The other randomized study included in the metanalysis found data very different from those in the study of Sagi-Dain, with an episiotomy rate of about 1– 2%. However, also in this study, the rate was similar in the two groups: 1.6% in the selective group and 1.7% in the non-episiotomy group [5]. This means that when Pereira et al. performed the metanalysis based on these two groups, they compared two populations identical in terms of episiotomy rate. It is obvious and easily predictable that, if we compare two identical groups, we will not find any difference in terms of outcomes. Therefore, it is not useful to compare a non-episiotomy group with an overall episiotomy rate of 12.8% (35/272) versus a selective episiotomy group with a very similar episiotomy rate of 15.4% (43/278). It does not seem possible to explain the following sentence of Pereira et al. in the abstract and text: “The non-episiotomy arm included two episiotomies (1.7% of deliveries), whereas the selective episiotomy included 33 episiotomies (21.4%).” Therefore, in conclusion, I think that, unfortunately, this systematic review with metanalysis did not reach any reliable and accurate result on this topic.

中文翻译：

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致编辑的信：严重会阴部创伤的选择性会阴切开术与无会阴切开术：荟萃分析的系统评价

亲爱的编辑，我很感兴趣地阅读了 Pereira 等人撰写的荟萃分析系统评价。[1]。在过去的十年中，会阴切开术的作用已成为一个备受争议且与临床相关的话题。已经充分证明，除了手术阴道分娩外，与选择性政策相比，系统性会阴切开术政策与相关优势无关。然而，说会阴切开术在任何情况下都可能是女性生活质量的敌人是不正确的，因为这句话不是基于证据的 [2, 3]。Pereira 和合著者的优点是试图澄清关于非选择性会阴切开术政策与非选择性会阴切开术政策之间比较的当前证据。不幸的是，作者仅纳入了两篇随机文章 [4, 5]，这是第一个相关限制。然而，这篇论文最大的偏见是作者比较了两个完全相同的群体。事实上，SagiDain 的研究报告了选择性与非会阴切开术组的会阴切开率分别为 26.5% 和 21.4% (p = 0.35) [4]。荟萃分析中包括的另一项随机研究发现数据与 Sagi-Dain 研究中的数据非常不同，会阴切开率约为 1-2%。然而，在这项研究中，两组的发生率相似：选择性组为 1.6%，非会阴切开术组为 1.7% [5]。这意味着当佩雷拉等人。基于这两组进行荟萃分析，他们比较了两个在会阴切开率方面相同的人群。显而易见且容易预测的是，如果我们比较两个相同的组，我们不会发现结果有任何差异。所以，将总会阴切开率为 12.8% (35/272) 的非会阴切开术组与会阴切开率为 15.4% (43/278) 的选择性会阴切开术组进行比较是没有用的。似乎无法解释 Pereira 等人的以下句子。在摘要和文本中：“非会阴切开术手臂包括两次会阴切开术（占分娩的 1.7%），而选择性会阴切开术包括 33 次会阴切开术（21.4%）。” 因此，总而言之，我认为不幸的是，本次荟萃分析的系统评价并未就此主题得出任何可靠和准确的结果。在摘要和文本中：“非会阴切开术手臂包括两次会阴切开术（占分娩的 1.7%），而选择性会阴切开术包括 33 次会阴切开术（21.4%）。” 因此，总而言之，我认为不幸的是，本次荟萃分析的系统评价并未就此主题得出任何可靠和准确的结果。在摘要和文本中：“非会阴切开术手臂包括两次会阴切开术（占分娩的 1.7%），而选择性会阴切开术包括 33 次会阴切开术（21.4%）。” 因此，总而言之，我认为不幸的是，本次荟萃分析的系统评价并未就此主题得出任何可靠和准确的结果。