Fetal Hemoglobin Levels in Premature Newborns: Should we Reconsider Transfusion of Adult Donor Blood?

Purpose: Extremely low gestational age newborns (ELGANs, born<28 weeks) have the highest morbidity/mortality among newborns and treatment with a high fraction of inspired oxygen is a contributing factor. Outcomes may be improved by maintaining a high level of fetal hemoglobin (HbF) which increases oxygen saturation at a lower PaO2. The aim of this study is to evaluate the decline of HbF in the ELGANs after transfusion with adult donor packed red blood cells (pRBCs) in the newborn period.

Methods: ELGANs (n=16) were followed prospectively from April 2019-March 2020 after IRB approval. Percent HbF (%HbF) was measured by hemoglobin electrophoresis on residual post-test complete blood count (CBC) specimens that were ordered per standard of care. Transfusion needs were recorded. Control %HbF levels (n=25) were measured from blood samples obtained from cord blood or during elective surgery (<6 months of age) from November 2018-November 2019 in otherwise non-transfused, healthy patients.

Results: Initial mean %HbF in ELGANs (n=16) was 92.2+1.3 (range 90.2-95.1%). Mean levels dropped to 61.1+11.1 (range 34.2-73.2%) after a single blood transfusion in 9 patients. All 9 patients required further blood transfusions and levels dropped to a mean of 35.6+6.3% after a single additional transfusion (n=5) or 29.3+10.1% after multiple (2-3) transfusions (n=4). Two patients (H, N) received 5 transfusions and their %HbF dropped to 15.3% and 17.6%, respectively. Two patients (B, G) died prior to further %HbF evaluation. Three patients (L, O, Q) had no transfusion need at discharge/time of data collection and %HbF remained within the normal range (>87%). Overall mortality in this group was 19% (3/16).

Conclusions: Percent fetal hemoglobin decreases precipitously when neonates are transfused with adult donor pRBCs. These data suggest that blood transfusion in the newborn period should favor cord blood that is rich in HbF.