Placental pathology in SARS-CoV-2 infected pregnancies: A single-institution retrospective cohort analysis.

Background: Our objectives were to determine 1) the prevalence and description of placental pathologic lesions in pregnancies complicated by SARS-CoV-2 infection compared to healthy controls and 2) whether the prevalence and/ or pattern of placental pathologic lesions differed in the few neonates who tested positive for SARS-CoV-2 in the first 48 hours of life at a busy urban county hospital.

Methods: This study included all pregnant mothers who tested positive for SARS-CoV-2 and delivered at our institution from March 2020 to June 2021, while control placentas were collected from term pregnancies without complications.

Results: Approximately 90% (n = 380/425) of placentas from pregnancies complicated by SARS-CoV-2 infections had placental pathologic lesions, compared to 32% (n = 16/50) of controls. The predominant lesions were acute histologic chorioamnionitis with or without fetal response (n = 209/380, 55%), maternal vascular malperfusion (n = 180/380, 47%), and other inflammatory lesions (n = 148/380, 39%). Only 14 (2.5%) infants tested positive for SARS-CoV-2 within the first 48 hours of life. There were no significant differences in placental histopathology between infants who tested positive vs. those that were negative for SARS-CoV-2. Placental lesions in mothers who tested positive for SARS-CoV-2 during the first vs. second vs. third pregnancy trimesters, were significantly different in the incidence of inflammatory placental pathologic lesions (n = 9/19, 53% vs. n = 37/98, 49% vs. n = 102/439, 31%, respectively; p < 0.01).

Conclusion: A significant proportion of women with SARS-CoV-2 infection during pregnancy at a single county hospital have inflammatory and vascular placental lesions at birth, raising questions regarding their downstream effects and clinical consequences.