key: cord-283430-k1ex9fes
authors: Smithgall, Marie C.; Liu‐Jarin, Xiaolin; Hamele‐Bena, Diane; Cimic, Adela; Mourad, Mirella; Debelenko, Larisa; Chen, Xiaowei
title: Third Trimester Placentas of SARS‐CoV‐2‐Positive Women: Histomorphology, including Viral Immunohistochemistry and in Situ Hybridization
date: 2020-07-21
journal: Histopathology
DOI: 10.1111/his.14215
sha: 
doc_id: 283430
cord_uid: k1ex9fes

AIMS: The wide‐variety of affected organ‐systems associated with SARS‐CoV‐2 infection highlights the need for tissue‐specific evaluation. We compared placentas from SARS‐CoV‐2‐positive and negative women in our hospital in New York City, which became the epicenter of the COVID‐19 pandemic in March 2020. While some limited studies have been published on placentas from SARS‐CoV‐2‐positive women to date, this study, in addition to describing histomorphology, utilizes in‐situ hybridization (ISH) for the S‐gene encoding the spike‐protein and immunohistochemistry (IHC) with the monoclonal‐SARS‐CoV‐2 spike‐antibody 1A9 for placental evaluation. METHODS AND RESULTS: In this study, 51 singleton, third‐trimester placentas from SARS‐CoV‐2‐positive women and 25 singleton, third‐trimester placentas from SARS‐CoV‐2‐negative women were examined histomorphologically using the Amsterdam Criteria as well as with ISH and/or IHC. Corresponding clinical findings and neonatal outcomes also were recorded. While no specific histomorphologic changes related to SARS‐CoV‐2 were noted in the placentas, evidence of maternal/fetal vascular malperfusion was identified, with placentas from SARS‐CoV‐2‐positive women significantly more likely to show villous agglutination (p=0.003) and subchorionic thrombi (p=0.026) than placentas from SARS‐CoV‐2‐negative women. No evidence of direct viral involvement was identified using ISH and IHC. CONCLUSIONS: In this study, third trimester placentas from SARS‐CoV‐2‐positive women were more likely to show evidence of maternal/fetal vascular malperfusion; however, no evidence of direct viral involvement or vertical transmission was noted by ISH and IHC.

SARS-CoV-2 testing was positive in 15.4% of women presenting to L&D, 87.9% of whom were asymptomatic. 2 Pneumonias arising from any infectious etiology are an important cause of morbidity and mortality among pregnant women. Adverse outcomes include premature rupture of membranes, preterm labor, intrauterine fetal demise, intrauterine growth restriction, and neonatal death. 3 Though most SARS-CoV-2 cases are mild to moderate, severe disease, termed COVID-19, is devastating many communities. Many questions regarding its pathophysiology and impact on specific populations, including pregnant women, remain.

Studies to date regarding SARS-CoV-2 and placental pathology have been limited by the number of SARS-CoV-2 positive cases, 4, 5 and only one with a sample size of 5 cases has utilized in-situ hybridization (ISH) and immunohistochemistry (IHC) analyses. 6 In our study, we compared placental histopathology from 51 SARS-CoV-2-positive and 25 SARS-CoV-2negative women in their third-trimesters presenting to L&D, and tested placentas from SARS-CoV-2-positive mothers using ISH and/or IHC.

For this study, we examined placentas from 51 SARS-CoV-2-positive women, as documented in their electronic medical records, from 3/23/20 to 4/29/20, the peak of SARS-CoV-2 infection in New York City. Twenty-five selected consecutively received singleton Accepted Article third trimester placentas from SARS-CoV-2-negative women from the same time period were reviewed for comparison. All mothers were tested in L&D via nasopharyngeal swabs, using a RT-PCR test [2] . All neonates born to SARS-CoV-2-positive mothers were tested for SARS-CoV-2 immediately after birth using the same methodology.

All placentas were grossly examined and H&E-stained sections of umbilical cords, membranes, and discs, including fetal and maternal plates, were reviewed. The placentas from SARS-CoV-2-positive mothers were tested using in-situ hybridization (ISH) for the S- 

Of the 76 placentas in the study, maternal ages ranged from 19 to 47 years (mean: 29.2±6.1) for SARS-CoV-2-positive and 21 to 42 (mean: 32.3 ±5.7) for SARS-COV-2negative mothers. Of the 51 SARS-CoV-2-positive mothers, 51% (26) were asymptomatic.

Cough (61.5%), fever (53.8%), myalgia (26.9%), sore throat (11.5%) and fatigue (11.5%) were the most common symptoms. Although the majority of patients were either asymptomatic or exhibited mild symptoms, four (15.4%) had severe disease necessitating supplemental oxygen, treatment with experimental therapies (hydroxychloroquine, azithromycin, tocilizumab, Remdesivir) and, in one patient, intubation. Comorbidities, including obesity, hypertension, preeclampsia, diabetes, hypothyroidism and asthma, were

This article is protected by copyright. All rights reserved similar between SARS-CoV-2-positive and SARS-COV-2-negative mothers. Delivery methods and preterm delivery (<37 weeks of gestational age) also were similar between these two groups (Table 1) . No adverse perinatal outcomes were identified: all neonates from SARS-CoV-2-positive mothers had high (>7) 5-minute Apgar scores. No deaths were reported.

The majority of placental weights and fetal-placental weight ratios for SARS-CoV-2positive and SARS-COV-2-negative women were within 10 th -90 th percentile reference ranges. Placentas from SARS-CoV-2-positive women showed non-specific evidence of maternal/fetal vascular malperfusion, including subchorionic thrombi (Fig.1A) , intervillous thrombi (Fig.1B) , infarction (Fig.1C) , chorangiosis, segmental avascular-villi (Fig.1D) , fetal thrombotic vasculopathy (Fig.1E) , and villous agglutination (Fig.1F ). Of these, villous agglutination and subchorionic thrombi were significantly more likely to occur in placentas from SARS-CoV-2-positive women than SARS-CoV-2-negative women (p=0.026 and p=0.003, respectively). We found no statistically significant differences between placentas from symptomatic and asymptomatic SARS-CoV-2 positive women in terms of intervillous thrombi, infarction, chorangiosis, accelerated villous maturation, etc. (Table 2) . No lesions associated with direct viral involvement (viral cytopathic changes) were noted, and both ISH (Fig, 1G) and IHC (Fig. 1H) testing were negative in all tested placentas from SARS-CoV-2positive mothers. All neonates born to SARS-CoV-2-positive mothers tested negative for SARS-CoV-2. 

This article is protected by copyright. All rights reserved we did not see direct viral presence of SARS-CoV-2 in placentas by morphology, IHC, and ISH targeting the spike protein, similar to other studies. 6 Thus far, studies have reported similar clinical symptoms and outcomes between SARS-CoV-2-positive pregnant and SARS-CoV-2-positive non-pregnant women. 11 One report describes mortality of a SARS-CoV-2-positive pregnant woman. 12 However, to date, there have been no reported cases of definitive vertical transmission. [13] [14] [15] Studies from the previous SARS outbreak indicated that SARS was associated with higher incidences of spontaneous miscarriage, preterm delivery, and intrauterine growth restriction, but without vertical-transmission. 16 Placental pathologic features described in association with SARS, e.g., increases in intervillous or subchorionic fibrin and avascular fibrotic villi, 17 

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Potential maternal and infant outcome from coronavirus 2019-nCoV (SARS-CoV-2) infecting pregnant women: Lessons from SARS, MERS, and other human coronavirus infections

Placental Pathology in Covid-19 Positive Mothers: Preliminary Findings

Placental Pathology in COVID-19

Infants born to mothers with a new coronavirus (COVID-19)

Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records

Clinical analysis of 10 neonates born to mothers with 2019-nCoV pneumonia

Pregnancy and perinatal outcomes of women with severe acute respiratory syndrome

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Maternal vascular malperfusion of the placental bed associated with hypertensive disorders in the Boston Birth Cohort

Sampling and Definitions of Placental Lesions: Amsterdam Placental Workshop Group Consensus Statement

Prenatal diagnosis, clinical outcomes and associated pathology in pregnancies complicated by massive subchorionic thrombohematoma (Breus' mole)

* p-value based on Fisher's exact test Abbreviations: AII: Ascending intrauterine infection; DVA: Decidual vasculopathy

ACCVM: Accelerated villous maturity; DVH: Distal villous hypoplasia; VAG: Villous agglutination; IVT: Intervillous thrombus; SCT: Subchorionic thrombus

AVASCS: Avascular villi, segmental; FTV: Fetal thrombotic vasculopathy; CHORS: Chorangiosis; CVUE: Chronic villitis

The authors would like to thank Denice Tsao-Wei for the statistical analyses.

Marie C. Smithgall, Diane Hamele-Bena, and Xiaowei Chen: Conception, design, primary acquisition, data analysis, and writing of the manuscript.Xiaolin Liu-Jarin, Adela Cimic, Larisa Debelenko: Conception, design, and data acquisition Mirella Mourad: Clinical data acquisition.

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