Congenital infection of SARS-CoV-2 in live-born neonates: a population-based descriptive study

Objective This study aimed to evaluate the evidence of mother-to-child transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Methods This is a descriptive, multicenter, observational study in nine tertiary care hospitals throughout Spain. The study population was women with COVID-19 during pregnancy. Mother-to-child transmission was defined as positive real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) of SARS-CoV-2 in amniotic fluid, cord blood, placenta or neonatal nasopharyngeal swabs taken immediately after birth. Results We included 43 singleton pregnant women and one twin pregnancy, thus we obtained 45 samples of placenta, amniotic fluid and umbilical cord blood. The median gestational age at diagnosis was 34.7 weeks (range 14 to 41.3). The median interval between positive RT-PCR and delivery was 21.5 days (range 0 to 141 days). Fourteen women (31.8%, 95%CI 18.6-47.6%) were positive at the time of delivery. There was one singleton pregnancy with SARS-CoV-2 RT-PCR positive in the placenta, amniotic fluid and umbilical cord blood (2.2%, 95%CI 0.1-11.8%). Nasopharyngeal aspiration was performed on 38 neonates at birth, all of which were negative (0%, 95%CI 0-9.3%). In 11 neonates the nasopharyngeal aspiration was repeated at 24-48 hours, and one returned positive (9.1%, 95%CI 0.2-41.3%). Conclusions The presence of the SARS-CoV-2 in placenta, amniotic fluid and cord blood shows that mother-to-child transmission is possible but uncommon.