Umbilical cord bilirubin level and pre-discharge hyperbilirubinemia risk

To assess whether arterial umbilical cord bilirubin (aUCB) level at delivery predicts predischarge neonatal hyperbilirubinemia, facilitating a safe discharge from the hospital.

Prospective analysis of hospital biochemistry records identified near term and term infants with recorded aUCB and predischarge, at 36 h of life, capillary heal bilirubin (cHB), to identify those with a cutoff of bilirubin levels >9 mg/ml, >75th percentile on the nomogram of Bhutani et al.

Of 616 study neonates, median (IQR) aUCB and cHB levels were 1.5 mg % (IQR 0.7-2.2) and 7.7 mg % (IQR 6.6-8.9), respectively. The values resulted statistically correlated (Pearson correlation coefficient 0.26, p < .0001) and an increment of 1 mg/dl in aUCB was associated with an increment (Regression coefficient, 95% confidence interval) of mean cHB 0.49 (0.33-0.65, p < .0001). Among these, 143 (23.2%) neonates developed bilirubin levels >9 mg/ml at 36 h of life and multivariable analysis confirmed that cHB levels (OR 1.49, 95% CI 1.22-1.82; p < .0001) and vaginal delivery (OR 2.34, 95% CI 1.33-4.36; p = .005) were significantly associated with bilirubin levels >9 mg/ml.

These data suggest that aUCB should be added to the list of major risk factors for neonatal hyperbilirubinemia.