April recalls

A four-day-old term baby is deeply jaundiced with a total serum bilirubin of 460 micromol/L and a low conjugated fraction; the baby feeds well and is otherwise stable. His parents noticed the yellow colour spreading from his face down to his trunk and limbs over the past two days. He is breastfeeding well every two to three hours and producing adequate wet nappies, with no fever or lethargy. Most appropriate management?