I read with great interest the recent paper by Kaplan et al about post-phototherapy bilirubin rebound. The incidence of significant rebound bilirubin was reported as 13.3% (30/226); the large number of neonates who rebounded (26/30) were among those in whom phototherapy had been commenced ⩽72 hours.¹ We have conducted a similar study with a total of 375 newborns; the proportion of neonates with significant rebound bilirubin who required phototherapy was 5.1% (19/375); 16 of 19 were from the birth hospitalisation group (⩽48 hours).² The key factor to take into consideration (which is not standard and limits the value of evaluation of studies for meta-analysis or comparison), is the definition of rebound bilirubin level that may be presumed for reinstitution of phototherapy. Kaplan et al recommenced phototherapy at bilirubin values >256 μmol/l; their …