Objectives: To determine the incidence of severe hyperbilirubinaemia in the newborn, and to identify associated clinical and demographic variables, and short-term outcomes.
Design: Prospective, population-based study.
Setting: UK and Republic of Ireland, between 1 May 2003 and 31 May 2005.
Participants: Infants in the first month of life with severe hyperbilirubinaemia (maximum unconjugated serum bilirubin >/=510 micromol/l).
Results: 108 infants met the case definition, 106 from the UK and 2 from the Republic of Ireland. The UK incidence of severe hyperbilirubinaemia was 7.1/100 000 live births (95% CI 5.8 to 8.6). Only 20 cases presented in hospital; 88 were admitted with severe jaundice. 64 (60.4%) cases were male, and 56 (51.8%) were of ethnic minority origin. 87 (80.5%) cases were exclusively breast fed. Co-morbidity included haemolysis, dehydration, infection and bruising. 14 infants showed evidence of bilirubin encephalopathy, of whom 3 died. The UK incidence of bilirubin encephalopathy was 0.9/100 000 live births (95% CI 0.46 to 1.5).
Conclusions: This is the first large, prospective, population-based study of the incidence of severe hyperbilirubinaemia in the newborn. The clinical and demographic associations, and short-term outcomes identified, are the same as those reported recently in North America and Europe.