Transfusion reactions occur in 0.15% to 3.7% of all transfusions and can range from mild fevers to severe, life-threatening reactions. Since pregnancy is associated with changes in the immune system, researchers in Sweden sought to determine whether transfusion reactions are more common in postpartum blood transfusions. Based on data from the Swedish National Birth Registry, which is linked to the Stockholm Transfusion Database, 517,854 pregnant women were identified of which 2.4% (12,183) received a blood transfusion postpartum. Ninety-six transfusion reactions occurred in the study cohort (79 per 10,000 pregnant women), which was higher compared to non-pregnant women of similar ages who received blood transfusions in Sweden (40 per 10,000 non-pregnant women) (odds ratio, 2.0; 95% CI, 1.6-2.5). Preeclampsia, induction of labor, or a premature delivery are associated with increased risk for a transfusion reaction. These findings underscore the need to carefully monitor postpartum women for transfusion reactions.
