Edgren G, et al. - Three separately analyzed retrospective cohorts consisting of 34,662; 93,724; and 918,996 transfusion recipients, the contributors intended to study associations of donor sex and prior pregnancy with their mortality. Kaiser Permanente Northern California cohort, Recipient Epidemiology and Donor Evaluation Study-III cohort and the Scandinavian Donations and Transfusions cohort were taken and assessed. Among red blood cell transfusion recipients, no significant association was concluded by the authors between increased mortality and transfusions from female, previously pregnant, or sex-discordant donors.