LAUSR

Background To assess the postnatal rate of rise (ROR) of total serum bilirubin (TSB) in very low birth weight (VLBW) preterm infants, to determine risk factors associated with a rapid rise (>90th percentile), and to compare ROR and hour-specific TSB at postnatal 12–48 h with data of term infants retrieved from the literature. Methods Retrospective analysis of 2430 routine TSB concentrations obtained between birth and initiation of phototherapy in 483 VLBW infants. Results TSB increased by a median (interquartile range) ROR of 0.15 (0.11–0.19) mg/dL/h. The 50th percentile of TSB was below the 40th percentile of (near-)term counterparts at 12–48 h. TSB ROR correlated with the age at initiation ( R S  = −0.687; p  < 0.001) and the duration ( R S  = 0.444; p  < 0.001) of phototherapy. ROR >90th percentile (>0.25 mg/dL/h) was associated with lower gestational ages [27.2 (25.4–29.3) vs. 28.4 (26.4–30.4) weeks], lower birth weights [978 (665–1120) vs. 1045 (814–1300) g], and lower 5-min Apgar scores [7 (7–8) vs. 8 (7–9)]. Conclusion ROR of TSB is an indicator for early and prolonged phototherapy. While hour-specific TSB and ROR at 12–48 h are lower than those reported for (near-)term infants, TSB appears to rise more rapidly in infants with low gestational age, low birth weight, and low 5-min Apgar score.