There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies. This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique. A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from “strongly disagree”=1 to “strongly agree”=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated. A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa. Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

中文翻译：

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单胎妊娠中的前置血管：基于国际专家共识的诊断和临床管理

指导前置血管的诊断和治疗的数据有限。目前，已知的信息主要基于病例报告或系列和队列研究。本研究旨在通过焦点小组讨论和德尔菲法系统收集和分类专家意见，并就前置血管的诊断和临床治疗达成共识。进行了 4 轮焦点小组讨论和国际前置血管专家小组的 3 轮德尔菲调查。专家是根据他们关于前置血管的发表记录来选择的。首先，我们召开了由 20 名专家组成的焦点小组讨论小组，并就前置血管诊断和治疗中尚未解决的问题达成一致。然后将三轮匿名电子调查发送给全体专家小组。调查问题涉及前置血管的诊断和治疗，专家们被要求按照 5 点李克特量表进行评分（从“非常不同意”=1 到“强烈同意”=5）。共识被定义为中位数分数为 5。在每轮答复后，任何中位数分数≤3 的陈述都被视为没有达成共识并被排除在外。中位数为4分的陈述被修改并重新提交给下一轮专家。然后汇总共识和非共识声明。此次研究共邀请了68名国际专家参与，其中57名专家参与。专家们来自五大洲 13 个国家，对已发表的前置血管队列研究以及国家和国际学会指南的贡献超过 80%。第一轮、第二轮和第三轮的完成率分别为 84%、93% 和 91%，其中 71% 完成了所有 3 轮。专家组就前置血管的诊断和处理要点达成了26项共识，其中包括：（1）虽然对于前置血管的胎儿血管与宫颈内口之间的距离的定义尚未达成一致，但定义不应局限于2厘米的距离； (2) 所有妊娠均应筛查前置血管，常规检查胎盘索插入情况，并在妊娠中期解剖扫描时对宫颈上方区域进行彩色多普勒扫描； （3）孕中期发现低位胎盘或前置胎盘时，应在32周左右进行经阴道多普勒超声检查，以排除前置血管； （4）对无早产危险因素的无症状患者的门诊管理是否合理； (5)无症状的前置血管患者应在妊娠35～37周期间按计划剖宫产分娩； (6) 对于常规住院治疗、避免性交或使用 3 维超声诊断前置血管尚未达成一致。通过焦点小组讨论和德尔菲流程，国际专家小组就定义、筛选、前置血管的临床管理和分娩时间，这可以为新的临床指南的制定提供信息。