Since the outbreak of coronavirus disease 2019 (COVID-19), there has been a debate whether pregnant women are at a specific risk for COVID-19 and whether it might be vertically transmittable through the placenta. We present a series of five placentas of SARS coronavirus 2 (SARS-CoV-2)-positive women who had been diagnosed with mild symptoms of COVID-19 or had been asymptomatic before birth. We provide a detailed histopathologic description of morphological changes accompanied by an analysis of presence of SARS-CoV-2 in the placental tissue. All placentas were term deliveries (40th and 41st gestational weeks). One SARS-CoV-2-positive patient presented with cough and dyspnoea. This placenta showed prominent lymphohistiocytic villitis and intervillositis and signs of maternal and foetal malperfusion. Viral RNA was present in both placenta tissue and the umbilical cord and could be visualized by in situ hybridization in the decidua. SARS-CoV-2 tests were negative at the time of delivery of 3/5 women, and their placentas did not show increased inflammatory infiltrates. Signs of maternal and/or foetal malperfusion were present in 100% and 40% of cases, respectively. There was no transplacental transmission to the infants. In our cohort, we can document different time points regarding SARS-CoV-2 infection. In acute COVID-19, prominent lymphohistiocytic villitis may occur and might potentially be attributable to SARS-CoV-2 infection of the placenta. Furthermore, there are histopathological signs of maternal and foetal malperfusion, which might have a relationship to an altered coagulative or microangiopathic state induced by SARS-CoV-2, yet this cannot be proven considering a plethora of confounding factors.

中文翻译：

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SARS-CoV-2感染期间和之后的胎盘病理结果：绒毛炎和灌注不良的特征

自 2019 年冠状病毒病 (COVID-19) 爆发以来，一直存在争议，即孕妇是否具有 COVID-19 的特定风险以及它是否可能通过胎盘垂直传播。我们展示了一系列 5 个 SARS 冠状病毒 2 (SARS-CoV-2) 阳性女性的胎盘，这些女性被诊断出有轻微的 COVID-19 症状或出生前无症状。我们提供了形态学变化的详细组织病理学描述，并分析了胎盘组织中 SARS-CoV-2 的存在。所有胎盘都是足月分娩（第 40 和 41 孕周）。一名 SARS-CoV-2 阳性患者出现咳嗽和呼吸困难。该胎盘显示出明显的淋巴组织细胞绒毛炎和绒毛间炎以及母体和胎儿灌注不良的迹象。病毒 RNA 存在于胎盘组织和脐带中，可以通过蜕膜中的原位杂交观察到。3/5 妇女分娩时 SARS-CoV-2 检测呈阴性，她们的胎盘未显示炎症浸润增加。分别有 100% 和 40% 的病例存在母体和/或胎儿灌注不良的迹象。婴儿没有经胎盘传播。在我们的队列中，我们可以记录有关 SARS-CoV-2 感染的不同时间点。在急性 COVID-19 中，可能会出现明显的淋巴组织细胞绒毛炎，这可能与 SARS-CoV-2 胎盘感染有关。此外，存在母体和胎儿灌注不良的组织病理学迹象，这可能与 SARS-CoV-2 诱导的凝血或微血管病变状态改变有关，