Association of Elevated C‐Reactive Protein in Term Newborns With Neonatal Factors and Gut Microbiota

AIM: Plasma C-reactive protein (CRP) is widely used to assess neonatal infection, although mild, unexplained elevations are common in healthy newborns. We examined relationships between non-infectious CRP levels and neonatal factors, and early gut microbiota composition in term infants. METHODS: This study was conducted within the prospective Finnish HELMi birth cohort. We included 105 full-term infants with plasma CRP levels measured during the first four postnatal days. Perinatal data were retrieved from medical records. Faecal samples collected at 3 weeks underwent 16S rRNA gene sequencing. RESULTS: Initial CRP level was elevated (≥ 3 mg/L) in 57% of infants, with no diagnosis of an infection. CRP levels were not associated with maternal group B Streptococcus status, intrapartum antibiotics, early neonatal complications or delivery mode, except for higher levels on day three after spontaneous versus induced vaginal delivery. Gut microbiota composition at 3 weeks differed according to CRP status, with family Acidaminococcaceae being less prevalent when CRP was elevated. Birth mode, antibiotic exposure and umbilical artery pH in the asphyxia range (≤ 7.1) were associated with distinct microbial profiles. CONCLUSIONS: Mild CRP elevations in term newborns were associated with differences in early gut microbiota composition but poorly explained by perinatal clinical factors.