Vertical transmission of SARS‐CoV2 during pregnancy: A high‐risk cohort

Objective Identify the potential for and risk factors of SARS‐CoV‐2 vertical transmission. Methods Symptomatic pregnant women with COVID‐19 diagnosis in whom PCR for SARS‐CoV‐2 was performed at delivery using maternal serum and at least one of the biological samples: cord blood (CB), amniotic fluid (AF), colostrum and/or oropharyngeal swab (OPS) of the neonate. The association of parameters with maternal, AF and/or CB positivity and the influence of SARS‐CoV‐2 positivity in AF and/or CB on neonatal outcomes were investigated. Results Overall 73.4% (80/109) were admitted in hospital due to COVID‐19, 22.9% needed intensive care and there were four maternal deaths. Positive RT‐PCR for SARS‐CoV‐2 was observed in 14.7% of maternal blood, 13.9% of AF, 6.7% of CB, 2.1% of colostrum and 3.7% of OPS samples. The interval between COVID‐19 symptoms and delivery was inversely associated with SARS‐CoV‐2 positivity in the maternal blood (p = 0.002) and in the AF and/or CB (p = 0.049). Maternal viremia was associated with positivity for SARS‐CoV‐2 in AF and/or CB (p = 0.001). SARS‐CoV‐2 positivity in the compartments was not associated with neonatal outcomes. Conclusion Vertical transmission is possible in pregnant women with COVID‐19 and a shorter interval between maternal symptoms and delivery is an influencing factor. Key Points What is already known about this topic? Few studies systematically evaluated the presence of SARS‐CoV‐2 in biological samples such as amniotic fluid, cord blood, placenta and colostrum Vertical transmission is still uncertain in pregnant women with COVID‐19 What this study add? Vertical transmission is possible in pregnant women with COVID‐19 Maternal viremia is associated with positivity in amniotic fluid and/or cord blood A shorter interval between symptoms and delivery is an influential factor for vertical transmission