Viral pneumonia with influenza has been shown to increase the risk of mother and child. Previous outbreaks of coronavirus infection with SARS and MERS virus have also reported serious illness in the woman and child, but the studies are very limited and do not have comparable groups. "COVID-19 in pregnancy" investigates how infection with COVID19 affects outcomes for mothers and children. The project examines all births in Norway in the period 2020 to 2021 and compares the incidence of illness in the woman or child in cases where the woman has known COVID19 disease with a pregnancy in which the woman has not been ill. The project is a broad collaboration between several national centers and includes international partners. The purpose is to obtain more reliable figures for the incidence of illness and the percentage of women who become seriously ill. The project also investigates whether COVID-19 disease in a woman affects the health of the fetus and child, such as the risk of death, premature birth, or low birth weight. The project will provide ongoing information on pregnant women who need intensive care and the use of respiratory therapy and cardio-pulmonary machines in pregnant women. It is important to capture all pregnant women who have had COVID-19 and we will therefore link the medical birth register with other Norwegian health records. We will then be able to investigate the risk factors for serious illness and whether influenza and pneumonia vaccines had protective effects.