Fetal vascular malperfusion and other placental lesions in relation to maternal SARS-CoV-2 exposure: a case-control...

The morphologic characteristics of placentas associated with coronavirus disease-19 (COVID-19) have been described but with varying findings. Studies conducted at the onset of the pandemic reported frequency of Fetal Vascular Malperfusion (FVM), an umbrella term that describes occlusive vasculopathies that affect fetal circulation and their associated sequelae. Morphologic manifestations include thrombosis, avascular villi and vascular stromal karyorrhexis. Associated outcomes include fetal growth restriction, thromboembolic events such as neonatal stroke and fetal demise. Placental lesions associated with a severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection present a unique picture in histology, especially in the attempt to decipher the underlying pathophysiology of the disease. This study aimed to determine whether there was an association between maternal SARS-CoV-2 infection and placental findings of FVM and to describe the prevalence of other histopathological changes in placentas from COVID-19 exposed pregnant women.

Two hundred thirty-four (234) placentas, including 33 cases with features of FVM and 201 controls without FVM, were collected from women delivering in Aga Khan University Hospital, Nairobi, recruited between June 2021 and November 2022. Histological evaluation, as per the Amsterdam placental workshop group consensus, was performed. To determine the association, a univariate analysis was conducted using a Fisher's Exact test for categorical data.

Fetal vascular malperfusion was observed in 14.1% (n = 33) of placentas. Of these, 45.5% (n = 15) were from SARS-CoV-2 PCR-positive mothers, whereas 54.5% (n = 18) were PCR-negative. Placentas from 201 participants did not show features of FVM. Of these, 59 (29.4%) placentas were from PCR/antigen SARS-CoV-2 positive women, while 142 (70.6%) were from those who were PCR/antigen SARS-CoV-2 negative. No statistically significant association was observed between exposure to COVID-19 during pregnancy and FVM [OR = 2.01 (C1 95%:4.24); p = 0.069].

No statistically significant association between maternal SARS-CoV-2 infection during pregnancy and FVM was observed, however an association cannot be definitively excluded. Chorangiosis was frequently observed, suggesting possible hypoxia-related placental changes. Larger studies are needed to determine whether SARS-CoV-2 exposure contributes to these lesions.