A risk level of bilirubin in newborns is considered to be above the 95th percentile based on age-specific total serum bilirubin levels. This means that a baby's bilirubin level is higher than 95% of other babies of the same age.
The risk of bilirubin passing into the brain, a condition called acute bilirubin encephalopathy, increases when levels are high. This can cause serious neurological problems, including brain damage.
Risk factors for high bilirubin levels in newborns include:
- Premature birth (born at 36 weeks or less)
- ABO or Rh blood group problem
- Sibling who needed phototherapy for jaundice
- Asphyxia (lack of oxygen at birth)
- Significant lethargy
- Temperature instability
- Sepsis (blood infection)
- Acidosis (high acidity in the blood)
Other factors that can influence bilirubin levels include:
- Age: Bilirubin levels are highest in the first few days of life and then gradually decrease.
- Race: Babies of Asian or Hispanic descent tend to have higher bilirubin levels than babies of other races.
- Breastfeeding: Breastfed babies may have higher bilirubin levels than formula-fed babies.
Doctors will monitor bilirubin levels in newborns and may recommend phototherapy if levels are high. This treatment uses special lights to break down bilirubin in the baby's blood.