The SCBU database will be searched for neonates born at ≥ 28 weeks of gestation hospitalized for phototherapy between January 2009 and December 2014. The SCBU charts of these neonates will be manually researched to identify study participants which will be classified as NH reaching exchange transfusion threshold (cases) or as NH within moderate threshold (controls). Additionally neurological signs compatible with ABE that would likely be reported by the clinical staff will be searched in the clinical notes and coded as present/absent; those signs are: sleepiness, irritability, apnea, convulsions, abnormal position/tone, and abnormal cry. Those charts will be included into the cases.