Analysis of SARS-CoV-2 vertical transmission during pregnancy

TLDR

The impact of SARS‑CoV‑2 infection during pregnancy is still unclear. The study examined SARS‑CoV‑2 genomes, antibodies, and inflammatory gene expression in maternal and neonatal samples from 31 infected mothers. SARS‑CoV‑2 was detected in a few maternal and neonatal samples, with evidence of vertical transmission in three cases accompanied by strong inflammation, indicating that in‑utero transmission is possible but rare and may inform obstetric care.

Abstract

Abstract The impact of SARS-CoV-2 infection during gestation remains unclear. Here, we analyse the viral genome on maternal and newborns nasopharyngeal swabs, vaginal swabs, maternal and umbilical cord plasma, placenta and umbilical cord biopsies, amniotic fluids and milk from 31 mothers with SARS-CoV-2 infection. In addition, we also test specific anti-SARS-CoV-2 antibodies and expression of genes involved in inflammatory responses in placentas, and in maternal and umbilical cord plasma. We detect SARS-CoV-2 genome in one umbilical cord blood and in two at-term placentas, in one vaginal mucosa and in one milk specimen. Furthermore, we report the presence of specific anti-SARS-CoV-2 IgM and IgG antibodies in one umbilical cord blood and in one milk specimen. Finally, in the three documented cases of vertical transmission, SARS-CoV-2 infection was accompanied by a strong inflammatory response. Together, these data support the hypothesis that in utero SARS-CoV-2 vertical transmission, while low, is possible. These results might help defining proper obstetric management of COVID-19 pregnant women, or putative indications for mode and timing of delivery.