What is the frequency of bilirubin (total bilirubin) level monitoring during newborn phototherapy, and is less frequent monitoring supported by research if levels are decreasing?

From the Guidelines

Bilirubin levels during newborn phototherapy should be monitored at least every 2 hours during the escalation of care period, but for infants with declining bilirubin levels, the frequency of checks can potentially be reduced to every 12-24 hours, as supported by the most recent guidelines 1. When implementing a reduced monitoring schedule:

• Ensure the initial bilirubin level is not critically high
• Confirm a consistent downward trend in bilirubin levels over at least two consecutive measurements
• Monitor for any clinical signs of worsening jaundice
• Continue phototherapy without interruption The rationale for potentially reducing monitoring frequency is based on the predictable decline in bilirubin levels once effective phototherapy is established, as noted in the 2024 Pediatrics guidelines 1. However, it's crucial to maintain vigilance, as some infants may experience rebounds in bilirubin levels or have underlying conditions that affect bilirubin metabolism, and the decision to reduce monitoring frequency should be made on a case-by-case basis by the treating physician, taking into account the infant's individual risk factors and response to treatment, as outlined in the guidelines 1. In contrast to older guidelines 1, the most recent recommendations 1 prioritize a more individualized approach to monitoring, emphasizing the importance of considering the infant's TSB trajectory and underlying cause of hyperbilirubinemia when determining the frequency of bilirubin level checks.

From the Research

Frequency of Bilirubin Level Monitoring

• The frequency of bilirubin level monitoring during newborn phototherapy is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
• However, study 3 mentions that daily serum total bilirubin measurements were taken for the first 5 days of life for newborns with ABO incompatibility.
• Study 6 reviewed the charts of 193 infants born prior to 35 weeks of gestation and found that total serum bilirubin measurements were performed over each 12-hour interval during the first six days of life.

Less Frequent Monitoring

• Study 3 suggests that a more meticulous selection of patients and reduction in the magnitude of routine laboratory testing can safely reduce discomfort to infants with hyperbilirubinemia as well as costs.
• Study 5 found that transcutaneous bilirubin measurement can be safely used for the evaluation of bilirubin levels in newborn infants under phototherapy, which could potentially reduce the need for frequent blood draws.
• Study 6 highlights the need to develop guidelines to optimize hyperbilirubinemia screening among early preterm infants, which could include less frequent monitoring for certain groups of infants.

Decreasing Bilirubin Levels

• Study 3 found that in the "Normal" group, there was a consistent decrease in total serum bilirubin values shortly after phototherapy was begun.
• Study 5 found that the difference between serum bilirubin and patched transcutaneous bilirubin was not significant after 52 hours of phototherapy, suggesting that bilirubin levels may decrease during phototherapy.
• Study 4 found that a mean serum bilirubin level of > or =4 mg/dL at the sixth hour of life was determined to have the highest sensitivity and negative predictive value to predict the newborns who would develop significant hyperbilirubinemia, which could inform less frequent monitoring for infants with decreasing bilirubin levels 4.