When is phototherapy contraindicated in jaundiced neonates?

Phototherapy is contraindicated in cases of conjugated hyperbilirubinemia because this type of jaundice typically indicates an underlying pathological condition. Conjugated hyperbilirubinemia occurs when the liver cannot effectively process bilirubin, leading to an increase in direct (conjugated) bilirubin levels in the blood, which is less likely to be resolved by phototherapy.

In contrast, unconjugated hyperbilirubinemia, which can be caused by conditions like physiological jaundice and breastfeeding jaundice, is generally more amenable to treatment with phototherapy since these conditions often resolve as the neonate matures. Phototherapy works by transforming unconjugated bilirubin into a more water-soluble form that can be excreted without needing to undergo conjugation in the liver. Therefore, in cases of unconjugated hyperbilirubinemia, phototherapy is indicated, whereas its use should be avoided in conjugated hyperbilirubinemia due to the potential for masking a serious underlying condition and the ineffectiveness of phototherapy in addressing this specific issue.