Antioxidant vitamins and hyperbilirubinemia in neonates

Low antioxidant system may contribute to the severity of neonatal hyperbilirubinemia. The aim of this research was to explore the relationship between plasma vitamin E and C levels and the severity of hyperbilirubinemia in full-term neonates with normal glucose 6-phosphate dehydrogenase (G6PD) activities.

A total of 130 full-term healthy live birth neonates of healthy mothers with normal G6PD activity were included in this study. In addition to routine blood analysis, plasma total bilirubin, vitamin E and C levels and G6PD activity were measured on the first day of life. None of the neonates was ABO incompatible or anemic.

Neonates who did not develop hyperbilirubinemia (n=119) had a mean plasma bilirubin level of 65+/-24 micromol/l (median 58.1), while neonates who developed significant hyperbilirubinemia (n=11) had a mean plasma bilirubin level of 238+/-56 micromol/l (median 246.2) on the first day of life. Mean plasma vitamin C levels of neonates who developed hyperbilirubinemia were significantly lower than those who did not develop hyperbilirubinemia (87+/-22 micromol/l (median 89.4) vs. 132+/-36 micromol/l (median 127.7), respectively, P=0.0001). Similar results were observed for plasma vitamin E levels in neonates who did or did not develop hyperbilirubinemia (7.5+/-2 micromol/l (median 6.3) vs. 10.4+/-5 micromol/l (median 9.1), respectively, P=0.001). Hemoglobin and hematocrit were significantly lower in neonates who developed hyperbilirubinemia (P=0.0002 and P=0.0003, respectively), although gestational age and birth weight for the two groups showed no significant difference.

The results of the present work indicate that low level of plasma vitamins C and E are associated with significant hyperbilirubinemia in full-term neonates.