Third Trimester Placentas of SARS‐CoV‐2‐Positive Women: Histomorphology, including Viral Immunohistochemistry and in Situ Hybridization

Smithgall, Marie C.; Liu‐Jarin, Xiaolin; Hamele‐Bena, Diane; Cimic, Adela; Mourad, Mirella; Debelenko, Larisa; Chen, Xiaowei

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.