WASHINGTON, Oct. 17 (Xinhua) -- Men are more likely to die if they receive blood transfusions from a woman who has been pregnant, a new study suggested Tuesday.
The increased risk of death, however, was not seen in female recipients, according to the study in the Journal of the American Medical Association.
"The association of increased mortality among male patients who received transfusions from ever-pregnant donors suggests a possible mechanism based on immunologic changes occurring during pregnancy," Rutger Middelburg from Sanquin Research in the Netherlands and his colleagues wrote.
But they noted that further research is needed to "replicate these findings, determine their clinical significance, and identify the underlying mechanism."
The study included over 31,000 patients who received blood transfusions at six major Dutch hospitals between 2005 and 2015.
Nearly 4,000 people, or 13 percent, died during the study period.
It found that male recipients who received a transfusion from an ever-pregnant female donor had "a statistically significant increase" in mortality compared with those who received a transfusion from a male donor or from a female donor without a history of pregnancy.
There was, however, no significant association between pregnancy status of female blood donors and mortality among female recipients of blood transfusions.
Kevin McConway, professor at the Open University in Britain, who was not involved in the study, pointed out that the increase in mortality in men is "not huge."
"It's important not to read too much into this study, and I don't think there is yet any real cause for men to be particularly concerned about this issue if they need a blood transplant," McConway said.
"At least, I'm a man, and I wouldn't be concerned," he said.