Neonatal Top-Up Transfusions in Alloimmune Hemolytic Disease of the Newborn: Incidence and Risk Factors
27 April 2018 (online)
Introduction: Neonates with hemolytic disease of the fetus and newborn (HDFN) due to red cell alloimmunization often require top-up (red blood cell) transfusions to treat late anemia during the first 3 months of life. Our aim was to quantify the need for top-up transfusions in neonates treated with intrauterine transfusions (IUTs) and to design a risk model to determine risk factors for occurrence of late anemia.
Materials and Methods: Observational study of data collected from medical records of all (near-) term neonates (≥ 35 weeks of gestation) with HDFN due to maternal red cell alloimmunization admitted to the Leiden University Medical Center between January 2006 and December 2017. Treatment with top-up transfusions, the number of top-up transfusions, and the number of days after birth before the first top-up transfusion was given were recorded, as well as the test results concerning potential risk factors.
Results: In neonates who were treated with one or more IUT, 88% (168 out of 191) were additionally treated with top-up transfusions, compared with 61% (65 out of 106) neonates without an IUT (p < 0.001). The median number of postnatal transfusions per neonate was slightly higher in the non-IUT group: two (interquartile [IQR]: 1–3) in the non-IUT group, compared with two (IQR: 2–3) in the IUT group (p = 0.036).The median time from birth to the first top-up transfusion was 16.0 days in the IUT group, compared with 9.0 days without IUT (p = 0.072). On multivariate analysis, the necessity for treatment with an IUT was independently associated with treatment with one or more top-up transfusions (odds ratio [OR]: 6.62, 95% confidence interval [CI]: 2.72–16.13, p < 0.001). Treatment with exchange transfusion was an independent protective factor (OR: 0.12, 95% CI: 0.05–0.32, p < 0.001).
Conclusion: Top-up transfusions in HDFN are independently associated with IUTs which increase the risk of transfusions over sixfold. Exchange transfusion is a strong, independent protective factor which decreases the risk of top-up transfusion eightfold.