Newborns may experience physiological jaundice after birth, but due to various reasons, the jaundice may fade slower. Common causes include physiological dehydration, insufficient feeding, inadequate breast milk, or the baby having fewer and less smooth bowel movements, which can lead to physiological jaundice that also fades slowly. However, for physiological jaundice, it generally does not last more than four weeks in preterm infants and no more than two weeks in full-term infants. If the newborn's jaundice persists longer and fades slowly, pathological causes should be considered, such as whether it is due to hemolytic disease, neonatal infection, infant hepatitis, or biliary atresia.