Onset of jaundice in glucose-6-phosphate dehydrogenase-deficient neonates

Objective. We asked whether neonatal jaundice associated with glucose-6-pho sphate dehydrogenase (G-6-PD) deficiency commences either in utero or in th e immediate postnatal period and whether this perinatal bilirubinemia is th e precursor of the subsequent neonatal jaundice and hyperbilirubinemia. Methods. Mandatory serum total bilirubin (STB) determinations were performe d within 3 hours of birth, to reflect the in utero state (first STB), and o n the third day of life (second STB), with additional determinations as cli nically necessary, on healthy, term male neonates at high risk for G-6-PD d eficiency. G-6-PD Mediterranean mutation was determined by molecular means. G-6-PD-deficient neonates were compared with control participants. The rel ationship of first STB values to second STB and subsequent hyperbilirubinem ia (defined as STB greater than or equal to 256 mu mol/L [15.0 mg/dL]) was determined. Results. Both first and second STB values were significantly higher in the G-6-PD-deficient neonates (n = 52) than in control participants (n = 166; 5 0 +/- 12 mu mol/L vs 44 +/- 10 mu mol/L [2.9 +/- 0.7 mg/dL vs 2.6 +/- 0.6 m g/dL] and 174 +/- 52 mu mol/L vs 152 +/- 52 mu mol/L [10.2 +/- 3.1 mg/dL vs 8.9 +/- 3.0 mg/dL] for the first and second STB values, respectively). The rate of rise between these 2 points was greater in the G-6-PD-deficient ne onates (2.6 +/- 0.9 mu mol/L/h vs 2.2 +/- 0.9 mu mol/L/h [0.15 +/- 0.05 mg/ dL/h vs 0.13 +/- 0.05 mg/dL/h). Sixteen (30.8%) of the G-6-PD-deficient neo nates developed hyperbilirubinemia compared with 10 (6%) of control partici pants (relative risk: 5.11; 95% confidence interval: 2.47-10.56). In both G -6-PD-deficient and normal populations, first STB values correlated signifi cantly with both second STB values and with those who subsequently develope d hyperbilirubinemia. Significantly more G-6-PD-deficient neonates with a f irst STB value greater than or equal to the mean developed hyperbilirubinem ia compared with those with first STB less than the mean: 13 of 28 neonates versus 3 of 24 (relative risk: 3.7; 95% confidence interval: 1.20-11.51). This difference did not reach statistical significance in the control group . Conclusions. Higher first STB values, an increased risk of hyperbilirubinem ia in G-6-PD-deficient neonates with first STB value greater than or equal to the mean, and significant correlation between first STB values and secon d STB values and hyperbilirubinemia suggest that jaundice in G-6-PD-deficie nt neonates commences in the immediate perinatal period, most likely in ute ro.