Pre-phototherapy total serum bilirubin levels in extremely preterm infants

Background Extremely preterm infants are prone to hyperbilirubinemia and its sequelae. Currently recommended thresholds for initiating phototherapy in these newborns are consensus-based (CB). Methods A multi-site retrospective cohort study of 642 infants born at 24(0/7) to 28(6/7) weeks' gestation, between January 2013 and June 2017, was conducted at three NICUs in Canada. Pre-phototherapy TSB percentile levels at 24 h of age were generated and contrasted with published CB thresholds. Results Among infants born 24(0/7) to 25(6/7) weeks' gestation, the differences between our TSB percentiles vs. the CB threshold of 85.0 mu mol/L were 10.0 mu mol/L (95% CI, 6.0-16.0) at the 75th percentile and 35.3 mu mol/L (95% CI, 26.1-42.8) at the 95th percentile. Respectively, among infants born at 26(0/7) to 27(6/7) weeks, differences were 19.4 mu mol/L (95% CI, 16.8-23.4) and 43.3 mu mol/L (95% CI, 34.7-46.9). Born at 28(0/7) to 28(6/7) weeks' gestation, differences between our 75th and 95th TSB percentiles and the CB threshold of 103 mu mol/L were 6.9 mu mol/L (95% CI, 3.2-12.0) and 36.0 mu mol/L (95% CI, 31.0-44.3), respectively. Conclusions We provide statistically derived pre-phototherapy TSB levels that may clarify patterns of pre-phototherapy TSB levels in extremely preterm infants. Impact We present statistically derived pre-phototherapy total serum bilirubin levels in a cohort of extremely preterm infants. Most of these preterm infants received phototherapy-some at below currently published thresholds. There are notable differences between our statistically derived pre-phototherapy TSB levels and currently published lower limit TSB thresholds for phototherapy. Our study results assist in the understanding of pre-phototherapy TSB levels in extremely preterm infants.