What bilirubin level is concerning in a breastfeeding infant?

From the Guidelines

Bilirubin levels above 20 mg/dL (342 μmol/L) are generally considered concerning in breastfeeding infants and warrant immediate medical attention. However, the assessment should consider the infant's age in hours, gestational age, and other risk factors, as outlined in the technical report on phototherapy to prevent severe neonatal hyperbilirubinemia 1. For term, healthy breastfeeding infants, mild jaundice with levels between 12-15 mg/dL after 72 hours of life is often considered physiological breastfeeding jaundice.

• Key factors to consider include:
  • The infant's age in hours
  • Gestational age
  • Rate of rise of bilirubin levels (more than 0.3 mg/dL per hour in the first 24 hours or more than 0.2 mg/dL per hour thereafter) 1
  • Presence of risk factors for hemolysis or other underlying causes of hyperbilirubinemia
• Management may include:
  • More frequent breastfeeding (8-12 times daily)
  • Supplementation with formula if needed
  • Phototherapy for higher levels, with the goal of reducing TSB concentrations by more than 2 mg/dL (34 mmol/L) within 4 hours of initiation 1
  • In severe cases (>25 mg/dL), exchange transfusion to prevent kernicterus
• Early and frequent breastfeeding is recommended as it helps establish milk supply and promotes bilirubin excretion through increased stooling, though temporary interruption of breastfeeding may occasionally be recommended for 24-48 hours in cases of breast milk jaundice to confirm diagnosis.

From the Research

Bilirubin Levels in Breastfeeding Infants

Bilirubin levels can be a concern in breastfeeding infants, and several studies have investigated the effects of hyperbilirubinemia on breastfeeding.

• A study published in 2020 found that hyperbilirubinemia may have a negative effect on breastfeeding and milk intake, with bilirubin levels above 12 mg/dL adversely affecting breastfeeding 2.
• Another study from 2007 found that breastfed newborns with nonhemolytic hyperbilirubinemia had a slower response to phototherapy compared to mixed-fed newborns, with a bilirubin level of 12 mg/dL used as a threshold for phototherapy 3.
• A 1986 study found that breast-feeding was significantly associated with hyperbilirubinemia, even in the first three days of life, with a 95th percentile for breast-fed infants of 14.5 mg/dL compared to 11.4 mg/dL for bottle-fed infants 4.
• A 1993 controlled trial found that in breast-fed infants with hyperbilirubinemia, the majority of infants whose serum bilirubin levels reached 17 mg/dL would decline spontaneously and not reach 20 mg/dL 5.
• A 1992 study suggested that treatment for jaundice in term babies should be deferred to relatively high levels of serum bilirubin, with a goal of keeping bilirubin levels below 23.4 to 29.2 mg/dL in low-risk infants 6.

Concerning Bilirubin Levels

Based on these studies, concerning bilirubin levels in breastfeeding infants appear to be:

• Above 12 mg/dL, as this level was found to adversely affect breastfeeding 2.
• Above 15 mg/dL, as this level was suggested as a threshold for investigations in breast-fed infants 4.
• Above 17 mg/dL, as this level was used as a threshold for intervention in a controlled trial 5.
• Above 20 mg/dL, as this level was suggested as a threshold for phototherapy in breastfed newborns 3, 5.