Pathomorphological changes of the placenta in coronavirus disease (COVID 19)

Abstract

The aim of this research was to study the pathomorphological changes in the placenta in case of coronavirus disease (COVID-19) in the anamnesis during different periods of gestation. Materials and methods. 53 placentas of women with the coronavirus disease (COVID-19) (RNA determination of the SARS-CoV-2) during the pregnancy were studied. The material was divided into the following groups: 1 and 2 – placentas in cases with a negative PCR test in full-term newborns who were born in satisfactory condition and high Apgar score. Group 1 (n = 29) – mother’s history of COVID-19 at 34–39 weeks of gestation; group 2 (n = 17) – mother’s history of COVID-19 at 23-33 weeks of gestation; 3 (n = 7) – placenta in case of antenatal fetal death. Results. Statistically significant differences were revealed between study groups: chorioamnionitis prevailed in group 1 (in 28 cases (96.6 %); confidence interval (CI): 86.4–100.0 %; P1-2 = 0.004); in groups 2 and 3 – arteriosclerosis (in 13 cases (76.5 %); CI: 52.2– 93.9 %; P1-2 = 0.0003 and in 7 cases (100 %); CI: 75.7–100.0 %; P1-3 = 0.001; respectively). COVID-19 was diagnosed in group 1 from 34 to 39 weeks of gestation (median 36.5), group 2 from 23 to 33 weeks (median 28.0), in group 3 from 13 to 32 weeks with a median of 24.5. Antenatal fetal death was observed between 14 and 41 weeks (median 31.4). Conclusions. Pathomorphological changes in the placenta in the coronavirus disease COVID-19 depended on the duration of the post-COVID interval (the time interval from the diagnosis of COVID-19 and the moment of delivery), due to the sequential change in the phases of the inflammatory process: alteration, exudation and proliferation, followed by fibrosis. The formation of acute placental insufficiency in coronavirus disease COVID-19, diagnosed up to 1–6 weeks to delivery, is associated with the development of severe disorders of circulation and acute exudative inflammatory reactions of varying severity. The formation of chronic placental insufficiency is associated with the proliferative stage of inflammation. These changes lead to the development of fibrosis in the wall of arterioles and intervillous space. The most significant structural changes in the placenta, leading to placental insufficiency, were observed in group 2 – at the time of infection in the period from 23–33 weeks of pregnancy. Coronavirus disease COVID-19 in the mother in the second trimester of pregnancy is a risk factor for perinatal losses, which are caused by the changes in the placenta described above with an increase in the duration of the post-COVID interval.