Transcutaneous bilirubin nomogram for evaluating the risk of hyperbilirubinemia in Iranian healthy newborns.

Background: Hyperbilirubinemia, which is mostly benign, is one of the most common problems in neonates. This study was conducted to draw a skin bilirubin nomogram for evaluating the risk of hyperbilirubinemia requiring treatment.

Methods: This cross-sectional study recruited 1066 healthy infants. The first transcutaneous bilirubin (TcB) measurement was performed before hospital discharge and within 12-48 h of birth. The neonates were followed up for 6 days after discharge based on their age at the time of discharge. The neonates were divided into four groups based on the TcB values before discharge and age in hours, including the low-risk, medium-low-risk, medium-high-risk and high-risk groups. The percentage of neonates who progressed toward severe hyperbilirubinemia was then calculated in each percentile based on the follow-up TcB measurement. Stata software was used to draw the nomogram. Based on the TcB values at discharge and the neonate's age in hours, the skin bilirubin nomogram was drawn in 40, 75 and 95 percentiles.

Results: A total of 4.9% of the neonates were in the high-risk group, 18.9% in the medium-high-risk group, 34.8% in the medium-low-risk group and 41.2% in the low-risk group. The risk of severe jaundice in the follow-up of the neonates in the highest-risk to the lowest-risk groups was 48.9, 14.5, 9.7 and 3.3%, respectively.

Conclusion: The skin bilirubin nomogram can be used to predict severe hyperbilirubinemia in Iranian infants.