Neonatal ABO incompatibility. Complicated by hemoglobinuria and acute renal failure.

The authors present two infants with isoimmune hemolytic disease due to ABO incompatibility complicated by massive hemoglobinuria and secondary acute renal failure. This represents an incidence of 0.36% of all neonates with ABO hemolytic disease in the author's newborn population. Only two patients have been reported previously to have similar complications. Analysis of data of these four infants revealed the clinical characteristics of this complication of ABO incompatibility: 1) very low frequency; 2) early onset of hemoglobinuria (first voided urine) and of acute renal failure (first 2 days of life); 3) lack of correlation between the clinical presentation of hemolytic disease and appearance and severity of renal failure; 4) complete recovery of renal functions following intravenous fluid administration; and 5) normal renal radiologic investigations.