Intrauterine Fetal Demise in the Third Trimester of Pregnancy Associated With Mild Infection With the SARS-CoV-2 Delta Variant Without Protection From Vaccination.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a higher infection rate in pregnant women than age-matched adults. With increased infectivity and transmissibility, the Delta variant is predominant worldwide. METHODS: In this study, we describe intrauterine fetal demise in unvaccinated women with mild symptoms of SARS-CoV-2 Delta variant infection. RESULTS: Histology and elevated proinflammatory responses of the placenta suggest that fetal demise was associated with placental malperfusion due to Delta variant infection. CONCLUSIONS: This study suggests that the Delta variant can cause severe morbidity and mortality to fetuses. Vaccination should continue to be advocated and will likely continue to reduce SARS-CoV-2 infection risks for pregnant women and their fetuses.