Schwartz David A
1950 Grace Arbor Court, Atlanta, GA 30329, USA.
Viruses. 2022 Feb 23;14(3):458. doi: 10.3390/v14030458.
Stillbirth is a recently recognized complication of COVID-19 in pregnant women. Other congenitally transmitted infections from viruses, bacteria and parasites can cause stillbirth by infecting fetal organs following transplacental transmission of the agent from the maternal bloodstream. However, recent research on pregnant women with COVID-19 having stillbirths indicates that there is another mechanism of stillbirth that can occur in placentas infected with SARS-CoV-2. In these cases, viral infection of the placenta results in SARS-CoV-2 placentitis, a combination of concurrent destructive findings that include increased fibrin deposition which typically reaches the level of massive perivillous fibrin deposition, chronic histiocytic intervillositis and trophoblast necrosis. These three pathological lesions, in some cases together with placental hemorrhage, thrombohematomas and villitis, result in severe and diffuse placental parenchymal destruction. This pathology can involve greater than one-half of the placental volume, averaging 77% in the largest study of 68 cases, effectively rendering the placenta incapable of performing its function of oxygenating the fetus. This destructive placental process can lead to stillbirth and neonatal death via malperfusion and placental insufficiency which is independent of fetal infection. Fetal autopsies show no evidence that direct infection of fetal organs is contributory. Because all mothers examined have been unvaccinated, maternal vaccination may prevent viremia and consequent placental infection.
死产是新冠病毒感染孕妇后最近才被认识到的一种并发症。其他由病毒、细菌和寄生虫经胎盘传播引起的先天性感染,可通过感染胎儿器官导致死产。然而,最近对感染新冠病毒的死产孕妇的研究表明,感染了严重急性呼吸综合征冠状病毒2(SARS-CoV-2)的胎盘可能存在另一种导致死产的机制。在这些病例中,胎盘的病毒感染会导致SARS-CoV-2胎盘炎,这是一组同时出现的破坏性表现,包括纤维蛋白沉积增加,通常达到大量绒毛周围纤维蛋白沉积的程度、慢性组织细胞绒毛间炎和滋养层坏死。这三种病理损害,在某些情况下还伴有胎盘出血、血栓血肿和绒毛炎,会导致严重且弥漫性的胎盘实质破坏。这种病理改变可累及超过一半的胎盘体积,在一项对68例病例的最大规模研究中平均为77%,实际上使胎盘无法履行其为胎儿供氧的功能。这种破坏性的胎盘过程可通过灌注不良和胎盘功能不全导致死产和新生儿死亡,而与胎儿感染无关。胎儿尸检没有发现胎儿器官直接感染的证据。由于所有接受检查的母亲都未接种疫苗,因此母亲接种疫苗可能会预防病毒血症及随之而来的胎盘感染。