Prophylactic platelet transfusions, often used to support pregnant patients with conditions like fetal and neonatal alloimmune thrombocytopenia (FNAIT), frequently show limited effectiveness, with many patients failing to achieve adequate platelet increases and a substantial proportion developing transfusion resistance, according to a retrospective study published recently in Vox Sanguinis.
Researchers analyzed 106 pregnant women who received 192 platelet transfusions between 2016 and 2023 for thrombocytopeniaThrombocytopenia A platelet count that is lower than normal., a condition that can overlap with or complicate FNAITFetal and neonatal alloimmune thrombocytopenia A rare condition in which a mother’s immune system attacks fetal platelets, leading to dangerously low platelet levels before and/or after birth.. A suboptimal response, defined as a low corrected count increment 18 to 24 hours after transfusion, occurred in 117 of 192 episodes, or 60.9%. This means that in most cases, the transfusion did not raise platelet levels as expected, which may affect how clinicians manage bleeding risk in FNAIT and similar disorders.
“[O]ur study suggested that suboptimal transfusion response or [platelet transfusionPlatelet transfusion A treatment for newborns with very low platelet counts that ideally uses HPA-compatible or washed maternal platelets. refractoriness] occurred frequently in pregnant women with thrombocytopenia high, which was primarily associated with prior allogeneic platelet transfusions and thrombocytopenia severity,” explained the authors of this research.
Two key factors were independently linked to this poor response: a history of prior allogeneic platelet transfusion and severe thrombocytopeniaSevere thrombocytopenia A dangerously low platelet count, typically below 50,000 platelets per microliter and sometimes far lower in FNAIT., defined as platelet counts below 50 × 10⁹/L. More than half of the suboptimal responses occurred in patients with both risk factors. For patients with FNAIT, who may already have immune-mediated platelet destruction, these findings suggest that repeat transfusions could become less effective over time.
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In addition, 25 of the 106 women, or 23.6%, developed platelet transfusion refractoriness, meaning at least two consecutive transfusions failed to work. This complication was associated with maternal age older than 35 years, prior platelet transfusion, gestational age under 37 weeks, severe thrombocytopenia and immune thrombocytopenia. These risks may overlap with patients affected by or monitored for FNAIT, where immune factors also play a central role.
Importantly, patients with transfusion refractoriness did not have higher rates of bleeding, maternal death or need for additional blood products. However, they experienced longer hospital stays, more frequent transfers to intensive care and slower recovery of platelet counts, lasting up to 42 days after delivery. They were also more likely to have preterm infants with lower birth weights.
For patients, including those navigating FNAIT, these findings highlight that platelet transfusions are not always a reliable solution. While still essential in many cases, their benefits may be limited in certain high-risk situations. Understanding these limitations can help guide more personalized care, encourage closer monitoring and support research into better treatments that improve outcomes for both mothers and babies.
“Future perinatal studies should investigate pregnancy-specific [platelet transfusion refractoriness] underlying mechanisms and establish multidisciplinary management protocols to optimize maternal-fetal outcomes,” concluded the authors.
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