Pathomorphological Features of Placenta in Different Degrees of Severity of New Coronavirus Infection Suffered During Pregnancy

INTRODUCTION: A wide spread of infection caused by SARS-CoV-2 coronavirus (Severe Acute Respiratory Syndrome-related coronavirus 2 associated with a severe acute respiratory syndrome) in the population, high risks of infection in pregnant women and the lack of understanding of the mechanisms of invasion of the agent into the placenta and its effect on the perinatal outcomes, dictate the need for targeted investigation of the morphofunctional features of placentas of puerperia’s who have suffered this infection.

AIM: To identify pathomorphological alterations in placentas in a mild, moderate and severe course of the new coronavirus infection in women during pregnancy.

MATERIALS AND METHODS: A morphological survey research of 63 placentas of women who have suffered SARS-CoV-2 infection during pregnancy was conducted. The material was divided into groups with mild (n = 16), moderate (n = 35) and severe (n = 12) course of the disease. The control group included 25 placentas from women with physiological pregnancy. After standard fixation and histological preparation of the material, the tissue sections of 4 µm to 5 µm thickness were stained with hematoxylin and eosin.

RESULTS: It has been established that the new coronavirus infection runs with general pathological alterations in the placentas. In a mild course of the infectious process, inflammation in the basal (12.5%) and parietal (25.0%) decidual membrane, disorders in maternal (6.3%) and fetal (6.3%) hemocirculation were diagnosed. A moderate course of the disease was characterized by predominance of placentas with impaired differentiation of chorionic villi by dissociation type (74.3%, p = 0.0001) and of mononuclear deciduitis (57.1%, p = 0.008). In a severe course of SARS-CoV-2 infection, abnormalities in the form of placenta (58.3%, p = 0.004) and in the attachment of the umbilicus (58.3%, p = 0.03), villous infarctions (33.3%, p = 0.05), thrombosis in the maternal (63.7%, p = 0.005) and fetal (57.3%, p = 0.005) parts of vascular bed were noted.

CONCLUSION: Thus, the mild course of SARS-CoV-2 infection is characterized by chronic inflammation in the structural components of the placenta, the moderate course — by the dissociated development of cotyledons, the severe course — by disorders in hemocirculation in the form of infarctions and thrombosis.