Predicting anaemia and transfusion dependency in severe alloimmune haemolytic disease of the fetus and newborn in the first 3 months after birth

Infants with haemolytic disease of the fetus and newborn (HDFN) often require erythrocyte transfusions in the first 3 months of life. We aimed to evaluate the incidence, timing and potential predictors of transfusion-dependent anaemia. An observational cohort of 298 term and near-term infants with severe HDFN treated with or without intrauterine transfusion (IUT) was evaluated. Transfusions were administered to 88% (169/193) of infants with IUT and 60% (63/105) without IUT. The following potential predictors were associated with less anaemia: K compared to D immunisation [odds ratio (OR) 0 center dot 13, 95% confidence interval (CI): 0 center dot 03-0 center dot 55], higher reticulocyte count at birth [per 10 parts per thousand (parts per thousand) higher, OR 0 center dot 99, CI: 0 center dot 97-1 center dot 00] and exchange transfusion (OR 0 center dot 11, 95% CI: 0 center dot 03-0 center dot 50). Without IUT, these variables were: lower reticulocyte count at birth (per 10 parts per thousand lower, OR 1 center dot 02, 95% CI: 1 center dot 00-1 center dot 03), lower maximum bilirubin after birth (per 10 mu mol/l lower, OR 1 center dot 01, 95% CI: 1 center dot 01-1 center dot 02) and exchange transfusion (OR 0 center dot 07, 95% CI: 0 center dot 01-0 center dot 20). In conclusion, potential predictors for anaemia in infants with severe HDFN varied between infants treated with and without IUT and are useful for selecting subgroups of infants at increased risk of anaemia.