EGA Institute for Women's Health, Faculty of Population Health Sciences, University College London, London, United Kingdom; and the Department of Obstetrics and Gynecology, University of Utah Health Sciences Center, Salt Lake City, Utah.
Obstet Gynecol. 2020 Dec;136(6):1211-1216. doi: 10.1097/AOG.0000000000004175.
The most common anomalies of implantation of the placenta and umbilical cord include placenta previa, placenta accreta spectrum, and vasa previa, and are associated with considerable perinatal and maternal morbidity and mortality. There is moderate quality evidence that prenatal diagnosis of these conditions improves perinatal outcomes and the performance of ultrasound imaging in diagnosing them is considered excellent. The epidemiology of placenta previa is well known, and it is standard clinical practice to assess placental location at the routine screening second-trimester detailed fetal anatomy ultrasound examination. In contrast, the prevalence of placenta accreta spectrum and vasa previa in the general population is more difficult to evaluate because detailed confirmatory histopathologic data are not available in most studies. The sensitivity and specificity of ultrasonography for the diagnosis of these anomalies is also difficult to assess. Recent epidemiologic studies show an increase in the incidence of placental and umbilical cord implantation anomalies, which may be the result of increased use of assisted reproductive technology and cesarean delivery. There is good evidence to support targeted standardized protocols for women at high risk and that screening and diagnosing placenta accreta spectrum and vasa previa should be integrated into obstetric ultrasound training programs.
胎盘和脐带植入的最常见异常包括前置胎盘、胎盘植入谱系疾病和血管前置，这些异常与相当大的围产儿和孕产妇发病率和死亡率有关。有中等质量的证据表明，这些疾病的产前诊断可以改善围产儿结局，而超声成像在诊断这些疾病方面的性能被认为是极好的。前置胎盘的流行病学众所周知，在常规筛查中，评估胎盘位置是在第二孕期详细的胎儿解剖超声检查中进行的。相比之下，胎盘植入谱系疾病和血管前置在普通人群中的患病率更难评估，因为大多数研究都没有详细的确认性组织病理学数据。超声诊断这些异常的敏感性和特异性也难以评估。最近的流行病学研究表明，胎盘和脐带植入异常的发生率有所增加，这可能是辅助生殖技术和剖宫产使用率增加的结果。有充分的证据支持对高危妇女采用有针对性的标准化方案，并且筛查和诊断胎盘植入谱系疾病和血管前置应纳入产科超声培训计划。
