key: cord-0781151-e8e3lv79
authors: Zhang, Peilin; Heyman, Taryn; Salafia, Carolyn; Dygulska, Beata; Lederman, Sanford
title: Detection of SARS-CoV-2 in placentas with pathology and vertical transmission
date: 2020-08-03
journal: Am J Obstet Gynecol MFM
DOI: 10.1016/j.ajogmf.2020.100197
sha: 95acb6fc2d7a63c9fc868ef6e8d4d559782ebac8
doc_id: 781151
cord_uid: e8e3lv79

nan

Objective COVID19 pandemic in New York City causes significant mortalities in adult population. Pregnant women at late gestational age positive for SARS-CoV-2 showed mild symptoms in comparison to non-pregnant adults. Rare cases of newborn babies testing positive for the SARS-CoV2 virus within first 24 hours have been reported [1, 2] . Miscarriages in second trimesters were also reported related to maternal COVID19 [3] . Placental pathology has been studied in small case series with controversial results and the vertical transmission was reported in some cases [4] [5] [6] . We sought to examine the placental pathology and to localize the SARS-CoV2 viral particles within the placental tissue.

The case series study was approved by the institutional review board.

The placentas were submitted to routine pathology examination based on the institutional criteria of maternal and fetal conditions established previously. All placentas were fixed in formalin overnight and standard 2 four sections were taken for light microscopy. Routine pathology examination was performed based on the current Amsterdam placental examination guideline. Clinical and pathological features were collected and statistically analyzed using various programs of R-package. SARS-CoV2 in-situ hybridization was performed by using RNAscope reagent kit containing specific probe against viral M-spike RNA and Leica Bond III automated instrument following the manufacturer's instruction.

Immunostaining for CD68 and CD42b was performed to highlight the tissue macrophages and platelet aggregates using the Leica Bond III automated instrument for routine clinical application as described previously.

We examined 364 consecutive placentas from the mothers tested in our facilities since the universal testing policy was adopted in March 2020 including 74 positive and 290 negative for SARS-CoV2 by nasopharyngeal swab PCR method as previously described [1] .

Pathological examination of the placentas after delivery was performed and the clinical characteristics of the mothers were similar to those No positive placentas were identified by ISH in 10 placentas from PCRnegative mothers. One positive placenta for SARS-CoV2 by ISH was delivered by C-section at 35 weeks 6 days due to placental previa 4 associated with placental infarcts, and the newborn baby was tested positive by swab PCR at 24 hours, 48 hours and 7 days. The neonate was asymptomatic and discharged home. The other positive placenta was from a mother with 40 week gestation associated with no significant clinical and pathological features, and the baby was tested negative for SARS-CoV2 by swab PCR method within the first 24 hours.

ISH test for this placenta showed the presence of viral particles only within the endometrial glands but not in the syncytiotrophoblasts. All other neonates were tested negative by nasopharyngeal swab PCR methods.

The current study showed that SARS-COV2 viral particles are uncommon in placentas from PCR-positive mothers at late gestation.

There appears largely no relationship between the maternal COVID19 status and placental pathology. Neonatal testing for SARS-CoV2 by swab PCR also showed rare positive cases from positive mothers. The The authors disclose no financial conflict of interests. 

Universal Screening for SARS-CoV-2 in Women Admitted for Delivery

Clinical Characteristics of Pregnant Women with Covid-19 in Wuhan, China

Second-Trimester Miscarriage in a Pregnant Woman With SARS-CoV-2 Infection

Vertical transmission of COVID-19: SARS-CoV-2 RNA on the fetal side of the placenta in pregnancies with COVID-19 positive mothers and neonates at birth

Placental Pathology in COVID-19

Detection of SARS-COV-2 in Placental and Fetal Membrane Samples