Maternal and perinatal outcomes following pre-Delta, Delta, and Omicron SARS-CoV-2 variants infection among unvaccinated pregnant women in France and Switzerland: a prospective cohort study using the COVI-PREG registryGuillaume Favre, Clémence Houssin, Louise Ghesquière et al.|The Lancet Regional Health - Europe|2023Cited by 66