PurposeThis study aimed to determine the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among infants with neonatal indirect hyperbilirubinemia (NIH); compare G6PD-deficient and G6PD-normal patients regarding hyperbilirubinemia and need for exchange transfusions (ET); and assess risk factors for ET and kernicterus.MethodsThis is a case-control retrospective study. Medical records of NIH patients admitted to the Pediatric Department, Salmaniya Medical Complex, Bahrain, between January 2007 and June 2010 were reviewed. Data on sex, age at presentation, hospitalization duration, need for ET, hemoglobin (Hb) level, reticulocyte count, direct Coombs test, serum total and indirect bilirubin levels, thyroid function, blood and urine cultures, G6PD status, and blood groups were collected and compared between the G6PD-deficent and G6PD-normal patients.ResultsOf 1,159 NIH patients admitted, 1,129 were included, of whom 646 (57%) were male. Among 1,046 patients tested, 442 (42%) were G6PD deficient, 49 (4%) needed ET, and 11 (1%) had suspected Kernicterus. The G6PD-deficient patients were mainly male (P<0.0001), and had lower Hb levels (P<0.0001) and higher maximum bilirubin levels (P=0.001). More G6PD-deficient patients needed ET (P<0.0001). G6PD deficiency (P=0.006), lower Hb level (P=0.002), lower hematocrit count (P=0.02), higher bilirubin level (P<0.0001), higher maximal bilirubin level (P<0.0001), and positive blood culture result (P<0.0001) were significant risk factors for ET. Maximal bilirubin level was a significant risk factor for kernicterus (P=0.021) and independently related to ET (P=0.03).ConclusionG6PD deficiency is an important risk factor for severe NIH. In G6PD-deficent neonates, management of NIH should be hastened to avoid irreversible neurological complications.