Placental Pathology of the Third Trimester Pregnant Women from COVID-19

Abstract

Aims: To explore the clinical characteristics and placental pathological changes of pregnant women with 2019 novel coronavirus (CoV) disease (COVID-19) in the third trimester, and to assess the possibility of vertical transmission.Methods and results: The placenta tissues were evaluated by using immunohistochemistry for inflammatory cells and Hofbauer cells, and using severe acute respiratory syndrome (SARS) CoV-2 RNA Fluorescence In-Situ Hybridization (FISH) and SARS-CoV-2 spike protein immunofluorescence (IF) double staining. All Eight placentas from the third trimester pregnancy women were studied. all patients were cured, no clinical or serological evidence pointed to vertical transmission of SARS-CoV-2. Features of maternal vascular malperfusion (MVM) such as increased syncytial knots were present in all 8 cases (8/8), and increased focal perivillous fibrin depositions were presented in 7 cases (7/8). No significate inflammatory cell reaction was noted in the placenta. The number of macrophages and inflammatory cells such as T cells, B cells and plasma cells in the placental villous was not significantly increased in all cases. Moreover, all of eight cases demonstrated negative results by FISH using a SARS-CoV-2 virus RNA probe and by IF using a monoclonal antibody against SARS-CoV-2 spike protein. Conclusions: We found no evidence of vertical transmission and adverse maternal-fetal outcomes in the placentas of third trimester COVID-19 pregnancy women, which provided further information for the clinical management of those women in the third trimester. However, further studies are still needed for patients with infections in different stage of gestation, especially in first and second trimester.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infecting Pregnant Women and the Fetus, Intrauterine Transmission, and Placental Pathology During the Coronavirus Disease 2019 (COVID-19) Pandemic: It's Complicated

“…Histologic examination of the placentas revealed no statistically significant difference in the prevalence of 21 unique histopathological findings between the groups, mirroring the results of similar works. 28,29 As such, the study failed to support earlier [23][24][25][26][27] and current 22 contentions that fetal vascular malperfusion and/or maternal vascular malperfusion may represent SARS-CoV-2-associated placental insults. Afterward, immunohistochemical staining of select tissue sections for SARS-CoV-2 nucleocapsid protein was performed to facilitate the second goal of the investigation, namely, to look for evidence of placental infection by the virus itself.…”

“…Analyses of placentas from mothers with SARS-CoV-2 infection were initiated to help resolve these issues, but their results were inconclusive; they demonstrated a spectrum of pathology findings that varied significantly between studies. In some investigations there was evidence of maternal vascular malperfusion, 22 in others fetal vascular malperfusion, 23 and in some, both; [24][25][26] other investigators described inflammatory lesions including chronic histiocytic intervillositis, villitis, funisitis, and chorioamnionitis; [24][25][26] and others found no specific findings of COVID-19 in placentas from infected women. [27][28][29] One publication 29 was entitled "SARS-CoV-2 can infect the placenta and is not associated with specific placental histopathology…", adding to the spectrum of differing findings and conclusions of the placental pathology from coronavirus infection.…”

COVID-19 in pregnancy: placental pathological patterns and effect on perinatal outcome in five cases

“…This lesion can be can be considered an attempt to adapt to maternal malperfusion, with an increase in the vasculo-syncytial membranes at the expense of further villus branching and angiogenesis. We also detected in the same case a Tenney-Parker change, another MVU lesion that represents an abnormality of the trophoblast, which forms an excessive number of syncytial knots in response to hypoxia and represents a common finding in the placenta of women with COVID-19 [47,49].…”

“…According to the literature, these lesions are common in the placenta of COVID-19-positive women [7,[38][39][40][41][42][43][44][45][46][47][48][49] in the third trimester, and might be related to hypoxia. In cases of COVID-19 in pregnancy, hypoxia in the third trimester may be related to severe disease, particularly affecting the respiratory system [50], but may also be due to more common physiologically adaptive changes occurring in pregnancy, such as: -increased blood volume and oxygen consumption, increased uterine volum [51]; − systemic inflammatory or hypercoagulable state [7,40,52,53].…”

Empfehlungen zu SARS-CoV-2/COVID-19 in Schwangerschaft, Geburt und Wochenbett – Update November 2021 (Langfassung)

“…Ein Review berichtet sowohl fetale (35,3 %; 95 % KI 27,7-43,0 %) als auch maternale (46 %; 95 % KI 38-54 %) vaskuläre Malperfusionszeichen mit Hinweisen für intraplazentare Inflammation (Villiitis 8,7 %, Intervillosiitis 5,3 %, Chorioamnionitis 6 %), bei jedoch nur 21 % SARS-CoV-2-Positivität der Plazenten [207]. Maternale vaskuläre Malperfusionszeichen [208] sowie Mikrokalzifikation und Fibrinthromben, scheinen dabei die Hyperkogulabilität [209] im Rahmen der Infektion zu reflektieren. Plazenten nach SARS-CoV-2-Infektion der Mutter weisen neben thrombotischen und mikrovaskulären Veränderungen [210] auch erhöhte ACE2-Konzentration auf.…”