From the Guidelines
Neonatal bilirubin levels typically peak by day 5, and a 48-hour level of 185 is likely to increase further. Bilirubin levels in newborns generally peak between days 3-5 of life, as stated in the management guidelines for hyperbilirubinemia in newborn infants 35 or more weeks of gestation 1. A level of 185 μmol/L (or about 10.8 mg/dL) at 48 hours is considered elevated and warrants close monitoring. Key factors to consider include:
- The importance of promoting and supporting successful breastfeeding to help reduce bilirubin levels
- Performing a systematic assessment before discharge for the risk of severe hyperbilirubinemia
- Providing early and focused follow-up based on the risk assessment
- Considering treatment with phototherapy or exchange transfusion if indicated to prevent severe hyperbilirubinemia and potential bilirubin encephalopathy (kernicterus) 1. It's probable this level will continue to rise over the next 2-3 days before starting to decline. Parents and healthcare providers should watch for signs of jaundice intensifying, such as yellowing of the skin progressing down the body. Frequent feeding (every 2-3 hours) is important to help the baby pass bilirubin through stool and urine. If levels continue to rise significantly, phototherapy may be necessary, which involves exposing the baby's skin to special blue lights that help break down bilirubin so it can be more easily excreted. The rise in bilirubin is due to the breakdown of fetal hemoglobin, combined with the newborn's immature liver function which struggles to process and excrete bilirubin efficiently in the first days of life, as outlined in the guidelines for managing hyperbilirubinemia in newborn infants 1.
From the Research
Neonatal Bilirubin Peak and Increase
- Neonatal bilirubin typically peaks by day 3 to 5 of life 2
- A 48-hour bilirubin level of 185 is likely to increase, as bilirubin levels usually peak between 48 to 72 hours of life 3, 4, 5, 2
Factors Affecting Bilirubin Levels
- Gestational age: Infants at 37 weeks gestation are four times more likely to have a serum bilirubin level greater than 13 mg/dL than those at 40 weeks gestation 6
- Ethnic background: G6PD deficiency is more common in certain ethnic groups, such as those from Greece, Turkey, Sardinia, and Nigeria 6
- Family history: A history of jaundice in previous siblings or family members may increase the risk of hyperbilirubinemia 6, 4
Predicting Hyperbilirubinemia
- A serum bilirubin measurement on the first day of life can predict the development of significant hyperbilirubinemia later in life 5
- A critical bilirubin level of 6 mg/dL on the first day of life can predict nearly all term newborns who will have significant hyperbilirubinemia and require phototherapy treatment later in life 5
- An hour-specific percentile-based nomogram can be used to predict which newborn is at high risk, intermediate risk, and low risk for developing significant hyperbilirubinemia 4