Key messages
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Transfusing platelets (giving blood cells that form clots to stop bleeding) at higher platelet count levels (when there is less risk of bleeding) does not seem to decrease death or bleeding.
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Transfusing at a lower platelet level likely reduces platelet transfusions without increasing the risk of death or bleeding.
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Future studies are needed to know the exact platelet count at which babies should be given platelets based on their individual risks for bleeding.
What are platelets?
Platelets are blood cells that form clots to stop bleeding. A low platelet level (platelet level on a blood test of less than 150,000 platelets per microliter) is known as thrombocytopenia. Thrombocytopenia is common in premature or sick newborn babies and can increase their risk of bleeding.
How is thrombocytopenia treated?
Thrombocytopenia is commonly treated by giving platelets from donated blood. Platelets are given directly into a vein in a procedure called a transfusion. However, platelet transfusion itself may increase the risk of death and other harms, and experts in the field differ about whether a platelet transfusion should be done when babies' platelets are lower versus when they are higher.
What did we want to find out?
We wanted to find out if it is better to give platelets when platelet levels are higher compared to when they are lower in babies with thrombocytopenia. We wanted to know the effects of transfusion on death and bleeding, and on babies' development.
What did we do?
We searched for studies that looked at giving platelet transfusions to babies with thrombocytopenia. We compared and summarized the results of the studies and rated our confidence in the evidence based on factors such as study methods and sizes.
What did we find?
We found three studies (856 babies) that compared different platelet levels for treatment with a platelet transfusion. Two studies took place in high-income countries (the USA, Canada, the UK, Ireland, and the Netherlands), and one in a lower-middle-income country (India). One study looked at whether it was better to give a platelet transfusion when the platelets in babies were just a little low (mild thrombocytopenia) compared to if the platelets were low (moderate thrombocytopenia) (mild thrombocytopenia range). Another study looked at whether it was better to give a platelet transfusion when the platelets were just low (moderate thrombocytopenia) compared to if the platelets were very low (severe thrombocytopenia) (moderate thrombocytopenia range). The third study looked at whether it was better to give a platelet transfusion when the platelets were very low (severe thrombocytopenia) compared to if the platelets were extremely low (very severe thrombocytopenia) (severe thrombocytopenia range).
We found no difference between lower and higher platelet levels in death:
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mild thrombocytopenia range (1 study, 152 babies);
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moderate thrombocytopenia range (1 study, 44 babies);
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severe thrombocytopenia range (1 study, 656 babies).
We found no difference between lower and higher platelet levels in bleeding:
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mild thrombocytopenia range (not reported);
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moderate thrombocytopenia range (1 study, 44 babies);
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severe thrombocytopenia range (1 study, 658 babies).
We found that transfusing at a lower platelet level likely reduces platelet transfusions without increasing the risk of death or bleeding:
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mild thrombocytopenia range (1 study, 152 babies);
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moderate thrombocytopenia range (not reported);
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severe thrombocytopenia range (1 study, 659 babies).
What are the limitations of the evidence?
We have only moderate to very low confidence in the evidence. Our confidence is limited because the people doing the studies knew which treatment they were giving, and we only found three studies, all of which differed in the platelet levels studied. The studies also differed in whether they included babies who were already bleeding. The largest study did not include babies with bleeding.
How up-to-date is this evidence?
The evidence is current to June 2025.
Read the full abstract
Objectives
To assess the benefits and harms of more restrictive platelet transfusion thresholds compared to more liberal thresholds in thrombocytopenic neonates.
Search strategy
We searched CENTRAL, MEDLINE, Embase, Epistemonikos, and trial registries until June 2025. We checked the reference lists of included studies and systematic reviews where subject matter related to the intervention or population examined in this review.
Authors' conclusions
The available evidence is of moderate to very low certainty and comes from only three studies. We found no evidence of a benefit of higher transfusion thresholds for any outcomes of interest, including death or bleeding, when giving a platelet transfusion to babies with higher platelet count levels (when there is less risk of bleeding). Of note, prior individual studies using different methods of analysis have raised concerns regarding the use of higher thresholds. This suggests that the use of lower platelet transfusion thresholds likely reduces platelet transfusions without a concomitant increased risk of death or major bleeding, although there is some uncertainty for critical outcomes.
Funding
This Cochrane review is funded in part by Vermont Oxford Network.
Registration
Protocol (2024) DOI: 10.1002/14651858.CD015341
