Rebound hyperbilirubinemia in term infants after phototherapy

OBJECTIVE: To determine whether a rebound in serum bilirubin level occurs within 24 hours after discontinuation of phototherapy in term infants with hyperbilirubinemia.

METHODS: A retrospective medical record review of term infants with hyperbilirubinemia requiring phototherapy who were admitted over 24 months, June 1999 to December 2001, at King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia was completed. Total serum bilirubin levels (TSB) at and up to 24 hours after termination of phototherapy (follow-up levels) were recorded. The difference between mean TSB level at termination of phototherapy and at follow-up was calculated using the paired t test.

RESULTS: Three hundred and one infants, 53% (n=161) were boys, mean ± standard deviation (SD) for gestational age was 39.4 ± 1.4 weeks, mean birth weight was 3200 ± 600g, mean TSB ± SD at termination of phototherapy was 193 ± 46 micromole/ liter (mmol/l) and at follow-up was 188 ± 45 mmol/l for all infants with either positive or negative direct coombs' test results. The difference in mean TSB level at discontinuation of phototherapy and at follow-up was statistically significant, (t=3.12, P= 0.002). The mean TSB level at termination of phototherapy was 179 ± 47 mmol/l and at follow-up was 177 ± 47 mmol/l for 65 infants with positive direct coombs' test results. This difference was statistically insignificant (t=0.725, P=0.47). The mean time interval between the termination of phototherapy and the measurement of follow-up TSB level was 8.3 ± 5.3 hour.

CONCLUSION: The rebound of bilirubin level after termination of phototherapy in otherwise healthy term infants is minimal; thus measurement of serum bilirubin is not required after termination of phototherapy and adds unnecessary expense, prolongs hospitalization, or both.