BACKGROUND Medication abortion, with a combination of mifepristone and misoprostol, is highly effective and safe. However, there is insufficient evidence on efficacy and safety at very early gestations before a pregnancy can be visualized with ultrasonography. METHODS We conducted a multicenter, noninferiority, randomized, controlled trial involving women requesting medication abortion at up to 42 days of gestation with an unconfirmed intrauterine pregnancy on ultrasound examination (visualized as an empty cavity or a sac-like structure without a yolk sac or embryonic pole). Participants were randomly assigned to either immediate start of abortion (early-start group) or standard-care treatment delayed until intrauterine pregnancy was confirmed (standard group). The primary outcome was complete abortion. The noninferiority margin was set at 3.0 percentage points for the absolute between-group difference. RESULTS In total, 1504 women were included at 26 sites in nine countries and were randomly assigned to the early-start group (754 participants) or the standard group (750 participants). In an intention-to-treat analysis, a complete abortion occurred in 676 of 710 participants (95.2%) in the early-start group and in 656 of 688 (95.3%) in the standard group; the absolute between-group difference was -0.1 percentage points (95% confidence interval, -2.4 to 2.1). Ectopic pregnancies occurred in 10 of 741 participants (1.3%) in the early-start group and in 6 of 724 (0.8%) in the standard group, with one rupture before diagnosis (early-start group). Serious adverse events occurred in 12 of 737 participants (1.6%) in the early-start group and in 5 of 718 (0.7%) in the standard group (P = 0.10); the majority were uncomplicated hospitalizations for treatment of ectopic pregnancy or incomplete abortion. CONCLUSIONS Medication abortion before confirmed intrauterine pregnancy was noninferior to standard, delayed treatment with respect to complete abortion. (Funded by the Swedish Research Council and others; VEMA EudraCT number, 2018-003675-35; ClinicalTrials.gov number, NCT03989869.).

中文翻译：

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极早期药物流产的随机试验。


背景 米非司酮和米索前列醇联合使用的药物流产非常有效和安全。然而，在妊娠早期可以通过超声观察观察妊娠之前的疗效和安全性，证据不足。方法 我们进行了一项多中心、非劣效性、随机、对照试验，涉及在妊娠 42 天内要求药物流产且超声检查未证实宫内妊娠的妇女（可视化为空腔或囊状结构，无卵黄囊或胚胎极）。参与者被随机分配到立即开始流产组（早期开始组）或延迟至确认宫内妊娠的标准护理治疗组（标准组）。主要结局是完全流产。绝对组间差异的非劣效性边际设定为 3.0 个百分点。结果 共有 1504 名女性在 9 个国家的 26 个地点被纳入，并被随机分配到早期启动组（754 名参与者）或标准组（750 名参与者）。在意向性治疗分析中，早产组 710 名参与者中有 676 名 （95.2%） 发生完全流产，标准组 688 名参与者中有 656 名 （95.3%） 发生完全流产;绝对组间差异为 -0.1 个百分点 （95% 置信区间，-2.4 至 2.1）。早孕组 741 名参与者中有 10 名 （1.3%） 发生异位妊娠，标准组 724 名参与者中有 6 名 （0.8%） 发生异位妊娠，诊断前有 1 例破裂（早熟组）。早启动组 737 名参与者中有 12 名 （1.6%） 发生严重不良事件，标准组 718 名参与者中有 5 名 （0.7%） 发生严重不良事件 （P = 0.10);大多数是因异位妊娠或不全流产而住院治疗的无并发症。结论 在确诊宫内妊娠前进行药物流产不劣于标准延迟治疗，就完全流产而言。（由瑞典研究委员会和其他机构资助;VEMA EudraCT编号，2018-003675-35;ClinicalTrials.gov 号，NCT03989869.）。