Serum concentrations of C-reactive protein in healthy term-born Norwegian infants 48-72 hours after birth

Aim: To determine serum C-reactive protein (CRP) concentrations in healthy term-born infants shortly after birth.

Methods: We sampled blood from 182 infants along with the routine neonatal screening programme at 48-72 hours of age from consecutively recruited healthy infants without signs of infection and a gestational age (GA) of at least 37 weeks. The blood was stored at minus 20°C until analysis in one assay after the end of the study.

Results: The CRP levels were positively skewed. The median concentration was 5.0 mg/L, 48.9% of the neonates had values <5.0 mg/L, 19.8% ≥10.0 mg/L, 7.1% ≥20.0 mg/L and 1.1% (2 neonates) >30 mg/L. The CRP level was positively related to GA and duration of labour, slightly higher in boys than girls and after vaginal compared to Caesarean delivery.

Conclusion: In healthy neonates born at term, the CRP concentrations did not vary substantially with various common perinatal clinical conditions, and levels above 30 mg/L were uncommon at two to three days of age.