Objective: To determine the presence of anti-SARS-CoV-2 antibodies in colostrum and mature milk in women who had SARS-CoV-2 infection during pregnancy or at delivery; to investigate the correlation between anti-SARS-CoV-2 antibodies in milk with antibody in maternal blood, severity of infection and time-interval from active illness; and to evaluate immunoglobulin evolution from colostrum to mature milk. Design: prospective cohort-study Setting: six hospitals in Spain and Hong-Kong. Sample: pregnant women with confirmed SARS-CoV-2 infection during pregnancy or at delivery. Methods: Colostrum and mature milk were collected by manual expression with strict contact precautions. Colostrum samples were tested with rRT-PCR-SARS-CoV-2 and both, maternal milk and serum were tested against SARS-CoV-2 specific immunoglobulin M, A and G reactive to receptor binding domain of SARS-CoV-2 spike protein-1. Results: All rRT-PCR-SARS-CoV-2 tested negative. IgA and IgG were present in 111/135 (82.2%) and 2/135 (1.5%) colostrum samples and 27/81 (33.3%) and 0/81 mature milk samples, respectively. Concentrations of immunoglobulins were not associated with the timing of infection but women with SARS-CoV-2 pneumonia had higher levels of IgA and IgG in colostrum than those who were asymptomatic or had mild symptoms. Conclusion: No SARS-CoV-2 virus was found in human milk, however, high levels of antibodies were found in colostrum, specially IgA, irrespective of the time of infection. All women should be encouraged to breastfeed, undertaking strict contact precautions when there is active disease. Funding: Spanish Government grant (Instituto de Salud Carlos III: COV20/00188). Synlab Diagnostics’ Globales (Madrid, Spain). Perkin Elmer.

Objective: To analyse the longitudinal effect of a supervised mild-moderate physical exercise program during pregnancy on uteroplacental and fetal Doppler. Design: Planned secondary analysis of an RCT Setting: Hospital Universitario de Torrejón, Madrid-Spain Sample: 124 women were randomized at 12+0-15+6 weeks to exercise vs non-exercise. Methods: Obstetric appointments were scheduled at about 12, 20, 28 and 36 weeks of gestation. GEE models were adjusted to assess longitudinal changes in Doppler measurements according to randomization group. Main Outcome Measures: Fetal middle cerebral artery, umbilical artery, cerebral placental ratio and uterine artery pulsatility index, were longitudinally measured by Doppler ultrasound throughout gestation, and normalized by MoMs or z-score calculation Results: No significant differences in fetal or maternal Doppler measurements were found at any check-up time-points. However, umbilical artery behaved differently in the exercise group where, starting from a not significantly higher pulsatility index, it showed a continuous decrease during pregnancy to a lower level than the non-exercise group, in which it remained unmodified throughout pregnancy. Conclusion: A regular supervised mild-moderate exercise program during pregnancy does not deteriorate fetal or maternal Doppler, suggesting that fetal wellbeing is not compromised. UAPI z-score decreases during pregnancy in the exercise group, while it remains stable in the non-exercise group. Funding statement: Research Grants were provided by Hospital Universitario de Torrejón (Madrid, Spain), Universidad Politécnica de Madrid (Madrid, Spain), Sanitas Healthcare and iMaterna Foundation.