Department of Obstetrics and Gynecology, University Hospital Brugmann, Université Libre de Bruxelles, Brussels, Belgium.
Department of Obstetrics and Gynecology, UZ Brussels, Vrije Universiteit Brussel, Brussels Belgium.
Eur J Obstet Gynecol Reprod Biol. 2024 Jun;297:126-131. doi: 10.1016/j.ejogrb.2024.04.009. Epub 2024 Apr 9.
To simulate the outcomes of Boulvain's trial by using magnetic resonance imaging (MRI) for estimated fetal weight (EFW) as a second-line confirmatory imaging.
Data derived from the Boulvain's trial and the study PREMACRO (PREdict MACROsomia) were used to simulate a 1000-patient trial. Boulvain's trial compared induction of labor (IOL) to expectant management in suspected macrosomia, whereas PREMACRO study compared the performance of ultrasound-EFW (US-EFW) and MRI-EFW in the prediction of birthweight. The primary outcome was the incidence of significant shoulder dystocia (SD). Cesarean delivery (CD), hyperbilirubinemia (HB), and IOL at < 39 weeks of gestation (WG) were selected as secondary outcomes. A subgroup analysis of the Boulvain's trial was performed to estimate the incidence of the primary and secondary outcomes in the true positive and false positive groups for the two study arms. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) for the prediction of macrosomia by MRI-EFW at 36 WG were calculated, and a decision tree was constructed for each outcome.
The PPV of US-EFW for the prediction of macrosomia in the PREMACRO trial was 56.3 %. MRI-EFW was superior to US-EFW as a predictive tool resulting in lower rates of induction for false-positive cases. Repeating Boulvain's trial using MRI-EFW as a second-line test would result in similar rates of SD (relative risk [RR]:0.36), CD (RR:0.84), and neonatal HB (RR:2.6), as in the original trial. Increasing the sensitivity and specificity of MRI-EFW resulted in a similar relative risk for SD as in Boulvain's trial, but with reduced rates of IOL < 39 WG, and improved the RR of CD in favor of IOL. We found an inverse relationship between IOL rate and incidence of SD for both US-EFW and MRI-EFW, although overall rates of IOL, CD, and neonatal HB would be lower with MRI-derived estimates of fetal weight.
The superior accuracy of MRI-EFW over US-EFW for the diagnosis of macrosomia could result in lower rates of IOL without compromising the relative advantages of the intervention but fails to demonstrate a significant benefit to justify a replication of the original trial using MRI-EFW as a second-line test.
通过磁共振成像（MRI）作为二线确认成像来模拟 Boulvain 试验的结果，以估计胎儿体重（EFW）。
使用来自 Boulvain 试验和 PREMACRO 研究的数据模拟了一项 1000 例患者的试验。Boulvain 试验比较了可疑巨大儿中引产（IOL）与期待管理的效果，而 PREMACRO 研究比较了超声-EFW（US-EFW）和 MRI-EFW 在预测出生体重方面的性能。主要结局是发生明显的肩部难产（SD）的发生率。选择剖宫产（CD）、高胆红素血症（HB）和 39 周前（WG）的 IOL 作为次要结局。对 Boulvain 试验进行了亚组分析，以估计两个研究臂的真阳性和假阳性组中主要和次要结局的发生率。计算了 MRI-EFW 在 36 周时预测巨大儿的敏感性、特异性、阳性和阴性预测值（PPV、NPV），并为每个结局构建了决策树。
在 PREMACRO 试验中，US-EFW 预测巨大儿的 PPV 为 56.3%。MRI-EFW 作为预测工具优于 US-EFW，从而导致假阳性病例的引产率降低。使用 MRI-EFW 作为二线测试重复 Boulvain 试验将导致与原始试验相似的 SD 发生率（相对风险[RR]：0.36）、CD（RR：0.84）和新生儿 HB（RR：2.6）。增加 MRI-EFW 的敏感性和特异性会导致与 Boulvain 试验相似的 SD 相对风险，但会降低 39 周前的 IOL 率，并改善有利于 IOL 的 CD 的 RR。我们发现，对于 US-EFW 和 MRI-EFW，IOL 率与 SD 的发生率之间存在反比关系，尽管 MRI 衍生的胎儿体重估计值总体上会降低 IOL、CD 和新生儿 HB 的发生率。
MRI-EFW 对 US-EFW 诊断巨大儿的准确性更高，可能会降低 IOL 的发生率，而不会影响干预的相对优势，但未能证明使用 MRI-EFW 作为二线测试复制原始试验具有明显的益处。
