Spectrum and outcome analysis of marked neonatal hyperbilirubinemia with blood group incompatibility

Background: Blood group mismatch between a mother and newborn carries a substantial risk for neonatal hyperbilirubinemia and kernicterus. In the current study, we investigate the spectrum and outcome of marked neonatal hyperbilirubinemia with blood group incompatibility. Methods: We retrospectively assessed a cohort of 413 neonates with peak total serum bilirubin (TSB) values ≤ 20 mg/dL between 1995 and 2007. Those with a gestational age <34 weeks, birth weight <2000 grams or G6PD deficiency were excluded. A total of 83 subjects with blood group incompatibility were enrolled. Neonates with unknown etiology of hyperbilirubinemia (except breast milk feeding) were selected as the controls (n = 168). Kernicterus referred to classic neurological signs after follow up for more than 1 year. Results: The clinical symptoms of acute bilirubin encephalopathy included apnea (2.4%), tachypnea (6.0%), fever (1.2%), irritability (2.4%), lethargy (4.8%), seizures (1.2%) and poor feeding (19.3%). Hyperbilirubinemia was more severe among babies with Rh incompatibility than those with ABO incompatibility. After double-volume exchange transfusion, the TSB levels significantly decreased from 25.8 ± 3.5 to 17.6 ± 4.0 mg/dL. Using logistic regression analysis, we found neonates with blood group incompatibility more often had a reticulocyte count > 7%, a hemoglobin value <13 g/dL and a peak TSB at age <3 days old than the controls (p <0.01). Furthermore, kernicterus was more common in neonates with blood group incompatibility (9.8%) than in the controls (0.0%) (p <0.01). Conclusions: This survey depicts the clinical profiles of babies with marked neonatal hyperbilirubinemia with blood group incompatibility. Neonates with blood group incompatibility often develop early-onset, hemolysis-mediated hyperbilirubinemia. Our findings show they are at great risk of kernicterus.