(HealthDay News) — There is no increased risk for mortality among patients receiving red blood cell transfusions from female, previously pregnant, or sex-discordant donors, according to a study published in the Journal of the American Medical Association.

Gustaf Edgren, MD, PhD, from the Karolinska Institutet in Stockholm, and colleagues used data from 3 retrospective cohorts of transfusion recipients (the Kaiser Permanente Northern California [KPNC; 34,662] and Recipient Epidemiology and Donor Evaluation Study-III [REDS-III; 93,724] databases [2013 through 2016] and the Scandinavian Donations and Transfusions [SCANDAT; 918,996] database [2003 through 2012]) to examine associations between blood donor sex and prior pregnancy and mortality of transfusion recipients.

The researchers found that the median number of red blood cell transfusions per patient was 3 in the KPNC cohort, 2 in the REDS-III cohort, and 3 in the SCANDAT cohort. The percentage of transfusions ranged from 39 to 43% for female donors, from 9 to 25% for previously pregnant donors, and from 44 to 50% for sex-discordant donors. Across cohorts, no statistically significant associations were noted between these three donor exposures and in-hospital mortality.

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“We proactively address potential risks to the blood supply, and we take this seriously,” Edgren said in a statement. “Transfusions are very common procedures, and our findings ensure that the current practice is safe and doesn’t need to be changed.”


Edgren G, Murphy EL, Brambilla DJ, et al. Association of Blood Donor Sex and Prior Pregnancy With Mortality Among Red Blood Cell Transfusion Recipients. JAMA. 2019;321(22):2183-2192. doi:10.1001/jama.2019.7084