Possible roles of bilirubin and breast milk in protection against retinopathy of prematurity

Aim: To explore the association of serum bilirubin level and breast milk feeding with retinopathy of prematurity (ROP) in preterm infants. Methods: We conducted a case–control study to examine the independent and combined effects of serum bilirubin and breast milk feeding on ROP risk in infants <32 weeks gestation or with birth weight <1500 g. Cases (66 infants with ROP) were matched with controls (66 infants without ROP) based on factors known to affect ROP risk. Results: When analysed using the paired t‐test, the peak bilirubin levels were lower in ROP cases than in controls (mean 7.2 vs. 7.9 mg/dL; p = 0.045). Using conditional logistic regression, we found a negative association between highest serum bilirubin level and risk of ROP (OR = 0.82 per 1‐mg/dL change in bilirubin; p = 0.06). There was no significant association between breast milk feeding and risk of ROP. Conclusion: Bilirubin may help to protect preterm infants against ROP.