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Pregnancy, preeclampsia linked to higher risk for transfusion reactions
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Pregnancy appeared associated with increased risk for transfusion reactions among women who received blood products, with preeclampsia as the most significant risk factor for complications, according to study results published in Blood Advances.
During pregnancy, alterations occur in the mother’s immune system to protect the fetus, and women with a history of pregnancies often have higher red cell, leukocyte and platelet antibodies, according to study background.
Study author Lars Thurn, PhD, graduate student at Karolinska Instituet in Stockholm, said this study was prompted in part by adverse reactions observed in women treated at this clinic.
“As obstetricians working in a hospital with approximately 9,000 deliveries annually, we regularly encounter women who have a postpartum hemorrhage,” Thurn told HemOnc Today. “In many situations, blood transfusions are necessary and can be lifesaving, but, in some cases, alternatives such as iron intravenously might be a better option.
“Two years ago, we experienced a cluster of adverse reactions to blood transfusions at our clinic,” Thurn added. “We found that in the majority of the cases, blood transfusions were given on a liberal indication, and other options might have been a better choice. The literature on transfusion reactions in women during pregnancy was scarce at that time, and the knowledge to guide clinicians in these situations was insufficient,”
In the retrospective, population-based study, Thurn and colleagues assessed data on all women who gave birth at more than 22 weeks in Stockholm County between 1990 and 2011. The researchers extracted data from the Swedish National Birth Registry and linked it to the Stockholm Transfusion Database to evaluate blood components given and whether women experienced transfusion reactions postpartum. Nonpregnant women who underwent blood transfusions during the same study interval (n = 89,684) served as controls.
The study cohort included 517,854 women (mean age, 31 years), of whom 12,183 (2.4%) underwent blood transfusions.
Results showed a 40% increase in postpartum transfusions during the 20-year study period, which researchers speculated may be due to factors such as older age and higher body fat among pregnant women today, as well as increasing use of in vitro fertilization and cesarean delivery.
The researchers documented 96 postpartum transfusion reactions, or 79 per 10,000 pregnant women compared with 40 per 10,000 nonpregnant women (OR = 2; 95% CI, 1.6-2.5). They identified preeclampsia as the single most significant risk factor for transfusion reactions (OR = 2.1; 95% CI, 1.7-2.6).
Prior cesarean section also increased the risk for placental complications and bleeding during later pregnancies. The study found that 26% of women who received more than 10 blood units postpartum had a previous cesarean section, compared with 8% of women who had no blood transfusion postpartum. Researchers observed a significantly higher risk for problems among women who received a combination of all three blood products (red blood cells, platelets and plasma).
“We do not know the exact cause of the increased risk,” Thurn told HemOnc Today. “During pregnancy the levels of erythrocyte-leukocyte and platelet antibodies are increased. HLA and leukocyte antibodies are both associated with several different types of transfusion reactions. Further, preeclampsia is more common late in pregnancy and is known to have an effect on the endothelium of the blood vessels. Both TRALI and TACO, two subtypes of transfusion reactions with a high risk for mortality, are reported to be associated with damage to the endothelium.”
The researchers acknowledged several limitations to their study, including the fact that it was not prospective and depended on the thoroughness of the reporting physician. They also cited a lack of access to transfusion reaction types and history as study limitations.
Thurn noted that these findings should increase knowledge of transfusion reactions among obstetricians, and ideally will lead to consideration of other options when appropriate.
“We hope our findings might increase the awareness of transfusion reactions among obstetricians and other clinicians that decide whether a patient should have a blood transfusion or not, especially in women with pregnancies complicated by preeclampsia,” Thurn told HemOnc Today. “Our findings might also lead to the consideration of alternatives to blood transfusion, such as administration of iron intravenously, in situations that are not life-threatening.” – by Jennifer Byrne
For more information:
Lars Thurn, PhD, can be reached at Department of Obstetrics and Gynecology, Skånes Universitetssjukvård, Region Skåne, SE-22185 Lund, Sweden; email: lars.thurn@ki.se.
Disclosures: The researchers report no relevant financial disclosures.
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