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

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

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.

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.

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.