Platelet transfusions are a potentially life-saving intervention that can be used to treat a variety of bleeding disorders, including fetal and neonatal alloimmune thrombocytopenia (FNAIT).
Transfusions for patients with FNAIT, however, may require special consideration. Because the disease is caused by a direct immune attack on fetal platelets, donor platelets must be carefully selected to avoid further triggering the immune response.
Why platelet transfusions are required for FNAIT
In patients with FNAIT, the maternal and fetal human platelet antigens (HPA) are incompatible with one another. This causes the mother’s immune system to produce antibodies that destroy the fetus’s platelets, leading to thrombocytopenia.
Read more about FNAIT treatment and care
Platelet transfusions are used to replenish the fetal platelets in order to combat thrombocytopenia. They can be administered both during pregnancy via an intrauterine transfusion or directly to the infant after delivery.
Donor platelet selection in FNAIT vs other bleeding disorders
When platelets are chosen for individuals with FNAIT, they are often screened to determine their HPA type. This is done to ensure that the donor platelets do not carry the same HPA type against which the maternal immune system is primed. The process of selecting compatible platelets for patients with FNAIT is known as HPA-matching.
In some other bleeding disorders, on the other hand, low platelet counts aren’t related to specific components of the platelets. In those cases, random donor platelets are used. These are platelets that are pooled together from multiple donors.
Random donor platelets are generally not checked for HPA type. If they are used for people with FNAIT, therefore, there is a chance that incompatible platelets may be given to the baby. If this happens, the delivered platelets could be destroyed, making the transfusion less effective.
When random donor platelets are used for FNAIT
In some instances, HPA-matched platelets aren’t readily available for patients with FNAIT. If platelet transfusions aren’t done promptly, however, it can increase the risk of serious complications like intracranial hemorrhage.
Even though matched platelets are preferred, it’s usually better to use random donor platelets rather than delay treatment. Although there is a higher likelihood that these platelets will be incompatible, it can still offer a temporary increase in platelet levels, which will help prevent severe outcomes in the long-run. If matched platelets become available during the course of treatment, patients may receive those instead.
What parents should know
If your doctor suggests a platelet transfusion for your baby, make sure they’re familiar with FNAIT and understand how the disease differs from other bleeding disorders. This way, they can see if nearby blood banks have HPA-matched platelets.
Don’t panic if HPA-matched platelets can’t be found right away. Even platelets that aren’t a perfect match can still be a life-saving option.
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