Omicron SARS-CoV-2 maternal infection is associated with favorable fetomaternal outcomes and fewer placental vascular malperfusion lesions compared with previous variants

Résumé fourni par la source

Background The SARS-CoV-2 pandemic, declared in March 2020, has affected over 570 million people worldwide. The impact on pregnant women and fetuses remains unclear, particularly with the Omicron variant, which appears to increase infection rates. This retrospective study describes fetal-maternal complications and placental features in Omicron-variant SARS-CoV-2 infections during pregnancy, and compares them with other variants and non-infected controls from published studies examining the association between SARS-CoV-2 infection and placental pathology Methods We analyzed all consecutive placentas referred to our hospital from May 2021 to March 2023, associated with proven Omicron-variant SARS-CoV-2 maternal infection during pregnancy. Results Among 315 placentas studied, fetal-maternal complication rates were comparable to the general population, including pre-eclampsia (0.6%), intrauterine growth restriction (5%), small for gestational age (9.1%), and preterm birth (3.1%).We observed a significant lower rate of hypotrophic placentas below the 10 th percentile (4.1% vs. 15.0%, p < 0.001), chronic deciduitis (3.8% vs 10.5%, p < 0.01), MVM (49.2% vs 58.8%, p < 0.01) and FVM lesions (7.6% vs 14.5%, p < 0.001) in Omicron cohort versus published data from studies of individuals with non-Omicron variant SARS-CoV-2. We did not observe an increased incidence of chronic inflammation nor SARS-cov-2 placentitis histologic triad in comparison to control cases from published data. A high rate of acute histological chorioamnionitis was observed, without increase incidence in preterm deliveries. The interval between infection and delivery did not alter placental features. Conclusion This large Omicron-variant placentas cohort highlighted clinically, an overall good outcome, and histologically significantly less vascular malperfusion and chronic deciduitis than in non-Omicron SARS-Cov-2 variants.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.