Villous chorion remodelling in term placentas following maternal COVID-19 infection: Association with the duration of the post-COVID interval
Year: 2026
Type: article
Study design: Observational Study
Abstract: Relevance. In placental tissue, SARS-CoV-2 targets cells characterised by the expression of angiotensin-converting enzyme 2 (ACE2), particularly endothelial cells, syncytiotrophoblasts and telocytes. Damage to these cells causes pyroptosis, inflammation and the development of arteriolosclerosis. Telocyte injury is associated with the loss of intercellular signalling, which leads to pathomorphological changes in the placenta. Aim. To investigate the remodelling of the villous chorion in pregnant women with coronavirus disease COVID-19. Materials and methods. A total of 152 placentas from term deliveries in women with COVID-19 were examined and divided into groups according to the duration of the post-COVID interval (from COVID-19 diagnosis to delivery). In Group I (n = 86), the PCI was 1-4 weeks, while in Group II (n = 66), it was 5-18 weeks. The control group comprised 50 placentas obtained after physiological deliveries before the onset of the COVID-19 pandemic. Microscopic, immunohistochemical and statistical research methods were used. COVID-19 in pregnant women was confirmed by a positive polymerase chain reaction (PCR) test for SARS-CoV-2 RNA, while the newborns were PCR-negative and had high Apgar scores. Quantitative differences in the stroma and vessels of the chorionic villi, as well as the percentage of stem and semi-stem chorionic villi, were determined using the ONLINE JPG TOOLS service. Results. The placentas in Group II were characterised by an increased percentage of stem and semi-stem chorionic villi: 33 (23; 47) versus 7 (7; 9); p < 0.001 in Group I. Disorders of the rheological properties of blood were observed in the main groups in the form of stasis and thrombosis in 100% of cases in Group I and 79% of cases in Group II. Stromal oedema led to changes in the ratio of vessels to stroma in the chorionic villi and to a reduction in the percentage of vessels: 29 (27-33). In Group II, the vascular lumen was restored – 46 (44-47), which was explained by a decrease in stromal oedema. Arteriolar endothelial necrosis was detected in 97.7% of observations in Group I and 6.1% in Group II. In Group I, destructive changes in telocytes were identified. In Group II, telocyte-like cells expressing α-SMA were detected, which does not exclude a transition to a myofibroblast phenotype during stromal remodelling in pregnant women with COVID-19, while fibrosis of the villous stroma may indicate transition towards fibroblasts. Compensatory mechanisms in the form of focal formation of small terminal villi were observed in cases involving the birth of infants with high Apgar scores.
Source: Medical Science of Ukraine (MSU)
Authors: Tetiana Savchuk, Ivan Leshchenko
Institution: Bogomolets National Medical University
Language: English
Subfield: Obstetrics and Gynecology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7222941321