Objective: To evaluate if SARS-CoV-2 is detectable in vaginal swabs and whether antibodies against SARS-CoV-2 are present in maternal and umbilical cord blood of pregnant women with COVID-19. Design: Prospective cohort study. Setting: Department of Obstetrics and Gynaecology, Copenhagen University Hospital – North Zealand, Denmark. Population: Pregnant women tested positive for SARS-CoV-2 in a pharyngeal swab between August 20th, 2020 and March 1st, 2021 who gave birth during the same period. Methods: Maternal blood sample and vaginal swabs were collected at inclusion. If included during pregnancy, these samples were repeated at delivery in addition to an umbilical cord blood sample. Swabs were analysed for SARS-CoV-2 and blood samples for SARS-CoV-2 total antibodies. Placental and neonatal swabs were performed on clinical indications. Main outcome measures: SARS-CoV-2 in vaginal swabs and SARS-CoV-2 total antibodies in maternal and umbilical cord blood. Results: We included 28 women, hereof 4 serious maternal or fetal outcomes including 1 neonatal death. Within the first eight days after a maternal positive pharyngeal swab, SARS-CoV-2 was detectable in two vaginal (2/28) and two placental swabs (2/4), whereas SARS-CoV-2 antibodies were detected in 1/13 women. After eight days, SARS-CoV-2 was not detectable in vaginal swabs and SARS-CoV-2 antibodies were observed in 19/21 of women. Antibodies in cord blood of seropositive mothers appeared after 16 days. Conclusion: Vertical transmission of SARS-CoV-2 seems plausible since SARS-CoV-2 is detectable in the vagina up to eight days after a positive pharyngeal swab at which time the neonate is not yet protected by antibodies.

Objective To identify risk factors for and outcomes after SARS-CoV-2 infection and severe COVID-19 in pregnancy Design Prospective population-based cohort study Setting Denmark Population All pregnancies between 1 March and 31 October 2020 Methods Using data from the Danish National Patient Register and Danish Microbiology Database and prospectively registered data from medical records, we compared women with a positive SARS-CoV-2 test during pregnancy to non-infected pregnant women. Severe infection was defined as hospital admission due to COVID-19. Main Outcome Measures Pregnancy, delivery, maternal, and neonatal outcomes. Results Among 82,682 pregnancies, 418 women had SARS-CoV-2 infection during pregnancy, corresponding to an incidence of 5.1 per 1000 pregnancies, 23 (5.5%) of which required hospital admission due to COVID-19. Risk factors for infection were asthma (OR 2.19 [1.41–3.41]) and being foreign born (OR 2.12 [1.70–2.64]). Risk factors for hospital admission due to COVID-19 included obesity (OR 2.74 [1.00–7.51]), smoking (OR 4.69 [1.58–13.90]), infection after gestational age in weeks (GA) 22 (GA 22–27: OR 3.77 [1.16–12.29]; GA 28–36: OR 4.76 [1.60–14.12]) and having asthma (OR 4.53 [1.39–14.79]). We found no difference in any obstetric or neonatal outcomes. Conclusions Severe outcomes of SARS-CoV-2 infection in pregnancy are rare. Funding The Danish Ministry of Higher Education and Science (Reg. 0237-00007B) and The Region of Southern Denmark and Region Zealand’s shared fund for joint health research projects (Reg. A767) Keywords Severe acute respiratory syndrome coronavirus 2; COVID-19; Obstetric delivery; Pregnancy complications; Pregnancy outcome; Cohort studies; Prospective studies.